Printed farms is a construction start up that has recently purchased the first COBOD BOD 2 printer in America. This gantry style system has been seen in Europe and was used by Kamp C to build a 2 story demo house there. The same system is also being used to build another 2 story home and also a 5 unit apartment complex.
I got the unique opportunity to be on site as Printed Farms began construction of their first building. The financier of the project decided their first build would be a 30×30 tractor shed. In Florida the hurricanes can have extremely high wind speeds. Fortunately the printed concrete is very sturdy with a strength over 5000 psi.
Although Printed Farms is a relatively new start up their founders Jim Ritter and Fredrik Wannius are not new to construction. They have financed construction projects across a range of uses and realized in that process how inefficient traditional construction models can be. Many of these struggles relate to organizing the large team of people that it takes to construct a building especially with the ongoing shortage of manual labor in many regions. Reducing manpower needed for the job is only a small part of the benefits realized with 3D printed construction technology. Data is everything and when you have a BOD 2 system plugged into a laptop onsite you have full control of the project at your fingertips.
The printer is equipped with various sensors to improve ease of use but it still requires some training to operate. If the ground or slab that you’re printing on is uneven, the BOD 2 is able to compensate for those irregularities, there is also a sensor in the extruder portion of the printer that alerts the concrete pump to send more through the hose. Generally the COBOD team would come out to train the print operator in person but due to typical 2020 complications the training process was completed online. Fredrik has become very competent with the massive 3D printer and feels like the online training was very good although he still collaborates with the COBOD team if he has any questions.
Printing outside exposed to the elements was a substantial feat achieved in this build. Many projects have needed protective tents surrounding them in order to maintain specific temperatures and humidity. When you need to build a temporary structure around an entire construction site things start to get expensive with the current solutions. Floridas natural climate allowed for this project to be completed outside.
Printed Farms has many fascinating projects in the pipeline that Fredrik discusses in the video. Although most of the printing is currently experimental, 3D printing in construction is at a transformative stage and soon its products will become consumer facing.
Recently I had the incredible opportunity to be one of the first Americans to see the 3D printed Fibonacci house under construction by Twente Additive Manufacturing. Maybe you saw it in the video I posted last week.
I also got to explore their facility and watch a few prints. I took the opportunity to ask pointed questions about the process so that I could compile the golden nuggets of knowledge directly from the experts during a print to share with you. For this weeks video, I have made an instructional introduction to operating a concrete 3D printer. There is a lot going on and so this short video barely scratches the surface of the various challenges one can face with different prints. Like Jim Ziemlanski says every print is different and with those differences come different challenges. At this point Jim has racked up many hours on the machine and is highly knowledgeable.
To understand what is involved on a basic level, here are the steps I’ve contrived from my observations during my time in the Twente Additive Manufacturing facility.
Test Run of first layer
Choosing 1K vs 2K material
Filling the mixer
Dialing in the details
Material consistency testing
Water Content Testing
Watch for problems
Analyze water content
Insert rebar & lifting hold
End the print gracefully
Designing the file is usually done in Rhino with the Grasshopper plugin. This is the industry standard software for parametric design in 3D printed construction. The file is then converted into a print path for the specific printer and its parameters can be updated in real time during a print if any changes need to be made thus eliminating the need to start over.
Next you test the first layer path of the printer to ensure that you are printing on a uniform high from the print surface. If you print surface is uneven it may be possible to compensate for that with your printer assuming it is a correctable margin (< 2cm). It is best to start on a perfectly flat surface because that will ultimately be the plane of your objects first layer.
Twente prints in two different material types, 1K and 2K. 1K is a simpler concrete mix developed by Laticrete. I’ve had Matthew Carli, the Director of Innovation at Laticrete on my podcast (Episode 3) to talk about the 3D printed construction space. The 2K material is developed by Baumit and requires a unique Baumit extruder along with an accelerant additive that is plugged into the nozzle and extruded with the proprietary material that it reacts with to allow the concrete to be printed on steeper angles, even permitting bridging and overhangs that would not be possible with regular concrete. As one may expect this more complicated material is much more expensive.
Loading the concrete mixer is the next step. The mixer used at TAM is loaded by hand but long term as the demand increases for 3D printed concrete parts it is likely they will use larger hoppers so they need to fill them less often.
Before printing, the concrete mix has to be dialed in properly. The settings need adjusting based off environmental factors like humidity and temperature. The hose from the mixer is nearly 20 ft long so it takes a while for the changes made to show in the end of the extruder. As the concrete drips from the extruder it is collected in 5G buckets and used for something that doesn’t need as particular parameters that way it doesn’t go to waste.
To verify the water content wt% a 50 gram sample of the wet extruded concrete is taken and microwaved to remove the water. It is then weighed again to determine how many grams of water were in it. This difference in weight allows you to find the wt%.
Before you start printing, back pressure must be applied to the extruder that way the concrete hose from the mixer stays full and doesn’t get any air pockets. This is done by hand with a spatula until the printer hits the print bed and starts on the first layer. This is similar to my Prusa MK3 desktop 3D printer that will extrude excess plastic which needs to be removed immediately before the print starts.
Printing is actually the easy part. If everything is going smoothly all you have to do is watch but at this scale, issues can be costly and time consuming to clean up so its best to keep an eye on it. Concrete has a tendency to clog so if the print shows signs of looking sloppy it may be best to pause the print, clear the clog, and resume from where you left off. Other issues can arise if the design doesn’t allow the concrete enough strength to support itself. Making a 3D model is easy but without an understanding for the limitations of a printer/material a novice could easily design something impossible to print. While printing, it would be wise to do more water wt% calculations as you go.
During the print it can be opportune to add supports in the form of rebar or supports for a hold that the piece can be lifted from in the future. This can be done by hand as long as it is placed evenly to allow the next concrete layer to print over top of it.
Ending the print is similar to starting it because once again you must apply back-pressure to the printer that way it doesn’t drip all over the freshly done print. This is once again done with a spatula by hand.
Just because the object is done, doesn’t mean you are. Next every part of the system that touched wet concrete has to be cleaned rigorously otherwise it could easily ruin the equipment. This paragraph is short but that process is long.
Next week we will take a look at the things TAM has printed around the grounds of their facility. There are all kinds of prints they have achieved that range from practical to creative. We will also take a look at how the offsite prints are transported to their final locations.
Recently I got the chance to speak with Dmitri Julius and Alexander Le Roux from Icon. If you haven’t heard, Icon is a startup that raise $35 Million A round led by Moderne Ventures to continue their progress developing the equipment and methodology for 3D printing buildings at scale.
Our initial scheduling got rained out. According to the head of communications at Icon, Brooke Baguess (who was instrumental in organizing our interview) filming after the rain is somewhat of an unintentional tradition for Icon. Also unintentionally, the day we had to reschedule for was 9/11. Coincidentally, Dmitri Julius had served in the US Marine Corps for 8 years earning the rank of sergeant starting in Feb 2003 only a year after the attack on the twin towers. I felt compelled to thank him and the rest of the troops/first responders for their service.
Dmitri still has the chance to interact with the US Marine Corps in his role as Vice President of Operations at Icon. In California, a project was completed to 3D print a ‘Vehicle Hide Structure’ that could serve to conceal a cargo or weaponized vehicle. Icon has an ongoing relationship with the military that should prove mutually beneficial for years to come.
Mobile Loaves and Fishes is the non-profit organization that Icon 3D printed these homes in Austin, TX. They’ve built a growing community of tiny homes that features an ICON made building as the welcome center. Homelessness is a rising issue in Austin, America, and around the world. ICON is poised to combat that with their technology. Dmitri mentioned that as Mobile Loaves and Fishes expands, ICON has stepped up to the plate and hopes to print many more homes for them in the future.
I asked Dmitri how his role at ICON changed pre and post funding. Dmitri expressed that at their startup no task is ‘beneath’ them and the team is willing to get their hands dirty on the job site when it’s needed.
Icon is on a bit of a hiring spree post funding and as they begin to fill those positions and the company expands the real changes will start to manifest. A big fundraise is huge for a startup but the effects are not fully realized until the money gets spent.
Next I spoke with Alexander Le Roux, a Co-Founder of Icon and also the CTO. Alex started his first 3D printed construction company in college called Vesta printers. He achieved a rudimentary design that demonstrated the ability to print concrete vertically high enough for a wall of a home.
After college he met Jason Ballard and Evan Loomis. Together the three of them founded Icon to take the technology to the next level.
Icon has developed a signature formula to print with that they call Lavacrete. It has a strength of 6000psi and as you can see in the building behind me (not even the latest version) it prints very smoothly. We constantly use the term ‘print’ to describe the automated pouring of concrete without any formwork, I can’t help but consider that in the mature stage of this presently niche industry companies may emulate the business model of paper printing companies and sell the printer at a loss to profit long term on the ink.
Alex and I talked a bit about the future of this technology. He mentioned how people tend to overestimate what can be done in a day but underestimate what can be done in 10 years. I wanted to know about projects on the horizon for Icon especially now that they have the funding to pursue bigger things and Alex said he can’t talk about it but I could tell he is very excited for what’s to come. If you have a project in mind that you’d like to do with Icon, Alex says to go to their website www.iconbuild.com and use their contact form. They won’t accept just any project but if it is a good fit they may be willing to work with you.
After our discussions I checked out one of the homes they built, I could only go in the living room at the time but it was very nice. It certainly had a tiny home vibe, the room actually featured a full kitchen as well. The space is well utilized and it doesn’t feel cheap like it would if it had been built with cinderblocks.
I recently had the opportunity to speak with the CEO of Rebartek AS Max(imillian) Trommer. His startup has developed an autonomous system of building rebar cages offsite that can latter be connected on site.
large projects take thousands of man-hours assembling rebar cages. This time consuming process can hold up the schedule especially in places where labor is hard to come by like Norway where Rebartek is headquartered. Currently Rebartek does their fabrication in their facility, but there are many exciting developments ahead for their tech. One concept being tested is a semi mobile gantry system that could be brought to a construction site to decrease the shipping expenses of the assembled cages. This makes a lot of sense if you consider the volume of an assembled rebar form vs the the volume the rebar would take up if it were unassembled and parallel.
Max started this company a couple years ago after working on a large bridge project and seeing firsthand how costly and time consuming it was to assemble the rebar. Initially he had a partner that helped him get the concept off the ground which was a key component for the concept because Max had no prior experience with automation robotics. Fast forward to now and his perspective on the complications of automation has changed drastically.
Their initial concept has been realized but with more experience, Rebartek is now fine tuning the system and using machine learning to achieve a variety of efficiencies.
Norway like many other countries faces a serious labor shortage that if left unsolved will lead to serious bottlenecks in the construction industry. Long term, a weak labor force means less buildings will be built and affordable housing access will decrease. Rebartek offers a solution to lighten a slice of this shortage and offer benefit to the construction schedule.
Max would like future engineers to consider how to pursue parametric design and code based solutions and recommends pythons as a very versatile useful tool for aspiring engineers looking to automate tasks.
As Rebartek continues to develop their technology and increase the efficiency of their product offering they will build a very compelling backlog of projects. It will take more projects to accurately depict the true time/cost savings because every project is so different but as always with technology over time there is no doubt we will see significant developments.
Check out the Rebartek Youtube channel to get an idea of how their tech works.
If you’re watching this video maybe you’ve seen some of my other videos where I tour 3D printed buildings and make content around the automated construction industry. Thanks to viewers like yourself, I now am getting access to opportunities and companies that previously had no interest in responding to me and because of you I’ll be able to make some really awesome videos coming up with some really awesome cutting edge companies.
3 times a week someone will call me asking if a 3D printed house can be built their neighborhood so I figured it would be helpful to make a video answering this simple question.
The short answer is yes but if you are looking to find the cheapest option, the tech is so new that it will be challenging to find someone that has a printer and the skills to use it who is willing to do a project with just one home. If you need a regular house built, the construction equipment for that project is available at every construction equipment rental outlet in the nation. By my estimations there currently under 100 large scale concrete 3D printers capable of printing a tall enough wall for a house.
To buy a 3D printed house, you will either have to make a deal directly with a company and pay them enough to convince them to use their very busy printer to make one house for you or buy the entire printer yourself which could cost more than the house.
Ultimately the dream of automation and technology is to decrease the price of work therefore allowing more people and organizations access to building tech that would have otherwise been out of reach. Unfortunately in order for this goal to be realized the industry needs to get bigger in order to realize efficiencies of scale. Think of the way Tesla first sold their expensive roadster car back in 2010, it was nearly 10x more expensive than the Tesla model 3 that you can buy today. Teslas use of cutting edge automation in their manufacturing plants gave them an edge that has become impossible to ignore but for a very long time before the economies of scale were realized, many people thought the industry of electric cars would never be profitable and for a long time Tesla was the most shorted company on the US stock exchange.
It’s no secret there is a serious labor shortage in construction here in America and many other countries around the globe. Some are concerned automation will replace jobs but think of it this way, there are so many different types of architecture and there is room for all of them. No matter what there will always be people that appreciate a handmade building over one built by machines.
The labor shortage is causing less new construction projects to be started. This is a major problem because according to freddiemac.com there is a shortage of 2.5million houses that need to be built in America.
I’ve been in Austin for the past few months and in the short time I’ve been here I’ve seen the number of tents on highway medians and under bridges double and housing is only getting more expensive.
The reality is unless more people start picking trade school over college homelessness and shelter insecurity will become an increasingly pressing matter.
If you do still want to buy a 3D printed house the first big question is will it be permitted in your local municipalities zoning laws and construction code. The construction technique is so new that it can be tricky to figure out the permitting situation.
If you want to make the process go smoothly then you can replicate traditional construction methods like CMU concrete blocks and fill columns of your printed concrete with rebar and traditional poured concrete. This is great for helping your municipality understand your project and getting though the paperwork quicker but because you will need to rely on traditional construction methods for all the structural elements of the building you will not realize the labor efficiencies.
To print the house using the printed concrete as a structural element of the building, you force your architect or engineer to venture into unknown territory. For a professional engineer to sign off on your plan, you will need to test the structure to failure. Yes, this means that if you want to build a 3D printed house that is structurally dependent on printed elements then you must build not one but two houses because one of them will need to be destroyed in order to be sure it is strong enough. This is an irritating barrier to entry that is not cost effective at all but it is absolutely critical to ensure the safety of every house built with this technology.
Thinking about the big picture this isn’t important, it’s only a temporary setback before enough data is collected for engineers to be able to accurately predict the strength of printed concrete elements every time, but for now every new structure must be proven to failure.
Short term, a clever way around this is to use repeating modular segments that are identical. If you can build a house out of 3 or 4 different modular segments for example, one for a wall, one for a corner, one for a window and one for a door, then you only need to test each of those segments once and they can be printed and repeated into infinity as long as you continue testing the concrete parameters.
If you wanted to build multiple similar units then this starts to make a lot more sense from a financial perspective because you always have the fixed cost of testing the new design so the more you build the more cost effective it gets.
One of the major benefits of 3D printing as opposed to prefab is that your machine is capable of infinite designs as opposed to prefab units that are identical. If you want to build 1000s of units of the same building for the lowest price and fastest time then prefab is your best bet. If you want units that look unique, 3D printing concrete becomes a much more interesting option but the current environment of regulation is holding the tech back from its full potential and rightfully so until the safety standards have been proven to a sufficient redundancy.
If you watched this entire video and you are still interested in getting a 3D printed house built for yourself knowing that being the first in your area to do so could be an expensive challenge then feel free to send an email to email@example.com and I can try to help.
If you have any questions don’t hesitate to let me know in the comments, I will try to answer them as best I can. I am working on redeveloping my website to include a job listings section as many companies competing in the race to automate construction are currently hiring especially Engineers and Architects with parametric design experience. If there is anything else in particular you think would be a good addition to the website let me know. I would like to provide a place where resources are available for people pursuing automated construction projects who need them.
If you’ve signed up for my mailing list already which includes 114 people at this point thank you, soon I will be sending the first one. for many people, their email inbox is a sacred place not to be bogged down with constant spam. Because of this I will make sure to only send emails when it is really worth it, maybe once or twice a month. It’s really meant for the people who have a deep interest in the long term prospect of automated construction, so if you’re only interested in the surface level project videos, then there is really no need for you to be on the mailing list.
I hope this video answers some of your questions and that you aren’t too disappointed you can’t just order a 3d printed house online and have it come in a week for under $100,000. In time all technology is improving incredibly fast and there is no reason to suspect that this technology won’t ultimately be the same.
If you want to learn more, check out my other videos where I cover 30 companies competing in 3D printing houses and tour various 3D printed buildings.
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Recently I got the opportunity to speak with a cofounder and the CFO of BeMore3D, Jose Luis Puchades Valencia. BeMore3D developed their own large scale concrete printer. They started as a 3D printing company with plastics but then developed a 2×2 meter printer as a proof of concept for printing concrete and from there they engineered the much larger printer that they use today.
Their biggest accomplishments to date are printing the first houses in both Spain and Africa. A focus on materials is at the heart of BeMore3D, they are constantly working on developing solutions and have experience fine tuning their mix with local ingredients to achieve a cost effective material to print with.
Jose told me that soon they will be unveiling a brand new website that will be transformative for their online presence and allow potential clients a whole new suite of functions including the process of buying a large scale concrete printer from BeMore3D. If you don’t want to wait for their new website you can contact them directly and place an order.
You can see in the house printed in Africa that the project goes through the whole day and as the sun moves there are drastic changes in the temperature and humidity. Concrete is sensitive to these factors so BeMore3D has included sensors in their printer that detect the ambient conditions for the project and adjust the parameters of the print like how much water is included in the mixture.
By using polymeric fibers in their concrete mix they are able to avoid using traditional steel supports and rebar. Eliminating the need for these things down the line will really help in maximizing the autonomy of the project. BeMore3D has many exciting projects lined up, I will be sure to track their accomplishments as they grow and spread their tech around the world.
There is a brand new company with 30 million in funding from silicon valley investors on the scene of Automated Construction that just came out of stealth mode in August 2020 and they’ve already delivered their first 2 units to customers.
Anyone who has done construction in California is familiar with the shortage of skilled laborers that is driving construction costs through the roof stick built housing in California costs $321. Mighty buildings has developed a solution decreasing this cost by 45%. Of course if the land has precarious circumstances the cost to build a secure foundation could be well over the expense for the home.
Mighty Buildings has been developing a solution for 3D printing unlike any I’ve seen on a large scale. With a custom printer and custom material, Mighty Buildings has differentiated their product significantly from materials based on Portland cement.
They call it synthetic stone. This material is lighter and supposedly stronger than concrete while also having an even higher thermal resistance which is an enormous benefit in the fiery land of California. Having a home that is fire resistant to this degree can be the difference between having a place to go back to after a natural disaster. Unlike concrete which cures over time, Mighty Buildings synthetic stone requires ultraviolet light to instantly harden which creates such a strong structure that they can 3D print a flat horizontal roof with a breadth up to 14ft.
All of their printing is done completely off site in one of their controlled facilities. After it is printed they use a crane to drop it into place. If it is a bigger home then it will be placed one section at a time but the smallest model is all in one. Down the line, they are looking towards solutions that will chemically seal the modular segments together so that the exterior shell can form a monolithic impenetrable structure. Achieving a monolithic structure offers many benefits like preventing water damage, and improving insulation which in turn can decrease your electric bill and improve the overall sustainability of your home.
Mighty buildings first home has already achieved a Certificate of Occupancy for their first residential homes and the occupant seems quite satisfied so far. This was made possible largely because they got the material they are using to be UL certified which goes a long way in cementing the legitimacy and trust in their product.
Mighty buildings is much more a tech startup than a construction company and that is evident in their approach to the entire process. It will be very exciting to see this company grow as they reach their early adopter customer base and begin to receive feedback on a large scale on what it is actually like to live in one of these homes. As with any tech I am positive that Mighty Buildings will be constantly trying to improve their product.
3D printing lends itself to intricacy because if you can make a really cool model or a unique parametric design then a 3D printer can achieve a level of detail that would be absolutely cost prohibitive otherwise. Designing models like that can take a long time but once they are made they can be printed over and over with the press of a button. Because of this there is no doubt that the Mighty Buildings catalog will be expanding drastically over time.
If they had no interest in offering a diverse lineup of products then they would have just build injection molds for their current product line but instead they opted for the infinitely more versatile option of 3D printing.
In the near future I have some really awesome videos planned with some really awesome companies, I am really looking forward to stepping up my game as I continue to research automated construction sharing my findings.
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Today, over an hour into an episode of the Automate Construction Podcast with Peter-Paul Van Der Berg and Marijke Aerts I realized it was not recording because I was signed into the wrong email address when I sent out the invitation to the meeting. After noticing this I was able to turn on QuickTime screen capture which could only record my screens visuals not the audio, I used my phone to record the meetings audio from my laptop and tried to sync up the sound. I will try to recount the missing details from the first portion of our conversation because it was a terrific eye opening experience for me and I’d like to share it.
The Kamp C team and its critical partners have 3D printed the first multi story house in Europe, specifically in Antwerp, Belgium. This was a showcase project meant to demonstrate the possibilities and practicality of 3D printed construction techniques. Peter-Paul said the printing of the house went off without a hitch and there were not big issues to be resolved which is incredible considering this house is the first of its kind in Europe.
The house printed in Belgium was done without any rebar or internal supports besides the printed concrete and the insulating foam. The interior wall and exterior wall of the building are completely separated with no bridging to maintain the best insulating properties. Many people have requested Kamp C build them a model of the house but Kamp C is not a typical construction company and they are primarily in the pursuit of exploring new technologies and strategies related to construction.
There is a newer project in Belgium for a recreational space that will be 3D printed that Kamp C has been assisting with. The number of projects in this space will increase over the coming years, one group plans on printing 7 units in Belgium by 2023.
Kamp C is not your typical construction company, they are funded in part by the local government in the pursuit of innovation and sustainability. They are working on building commercial buildings with ‘circular’ construction which means that over the course of multiple decades they will build 4 buildings, one at a time and after the life of the first one has expired it will be deconstructed and the materials from the first building will be used to rebuild the last, if the project is successful the parts from the other buildings will be reused many times over as well.
They also gave a really interesting example of what differentiates their strategies from traditional construction companies. In the circular building project they want to lease out the products of certain construction trades like windows and lighting so that the contractor is responsible for the life of the project not just the deliverable on the last day the final punch list is closed out. This strategy is being implemented in order to change the way construction is perceived and keep investors from cutting corners in order to get the job done quickly or cheaply when there are better long term solutions available.
It was very unique that an organization tied to the government was willing to hop on this podcast with me. One thing they mentioned is that when someone comes to them with an idea, first they say yes and then they figure out how to get it done. This open minded attitude and entrepreneurial spirit is what seems to drive Kamp C toward the unprecedented type projects they tend to work on. Governments can sometimes regulate and impede markets but by supporting Kamp C Belgium has made it clear they are dedicated to exploring cutting edge solutions. Belgium will see an advantage when these construction techniques catch on and they already have some experience.
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3D printed construction might be the most promising way to automate construction so recently many people have been pursuing the perfect mix for printing. Rheology is the study of how materials flow so that is the science being applied to concrete made for printing.
My name is Jarett Gross and I’ve gathered this information mostly from research featured at Digital Concrete 2020 to simplify some of the material science behind forward thinking disruptive construction methods.
These materials range from nearly free adobe mixtures of dirt and straw to ultra strong and highly engineered custom concrete hybrid mixtures that can be cost prohibitive in respect to affordable housing.
Currently most groups automating large forms are using unique mixtures of concrete engineered to have properties conducive to a sturdy structure.
The material needs to hold immediately exiting the machine. Generally that is either achieved by a stiff mortar or a thinner mix with an accelerant added at the point of extrusion to cure the concrete faster and achieve angles gravity otherwise would not permit. (1)
Thixopotry is a property that allows a mixture to flow when it is being moved but remain firm after it has been placed so this is behind many of the developments in this space.
Some of these mixes include various forms of supports which I will cover in an upcoming video, others are strong enough to support themselves like the project in Brazil by InovaHouse3D.
Many mixtures have been considered using Portland cement. Wollastonite micro fibers have been shown to enhance flexural strength without detriment to compressive strength. The same study shows printed concrete demonstrates anisotropic behavior, in other words like the grain of wood it fails easier parallel to the grain vs perpendicular to the grain (2)
Mixes can be thick or have more flow, these properties can be influenced by viscosity modifying admixtures’VMA’. NanoClay can improve the strength of the print but makes the mixture more susceptible to clogging to viscosity modifying admixtures can improve the flow. (3)
Two minute delay time between layers has 25-86% higher strength than a 15 minute interval it is important to get a monolithic structure (4)
Fly ash silica fume metakaolin limestone powder and quartz powder have been identified as having useful properties for printed concrete. Plasticizers, accelerators, retarders, and viscosity modifying agents can be used but increase cost dramatically (5)
Limestone can be implemented with less cement to decrease cost to print and improve sustainability.
Under a 25% replacement rate of limestone powder to cement, the impact on strength is within reasonable limits. (6)
Metakaolin leads to a more dry mix that is stronger after extrusion but more difficult to extrude. Fly Ash can be included to improve the printability. Adding polypropylene fibers was shown to increase the yeild stress. (7)
Here are the details from a mix made in a region where dune sand is an abundant resource (8)
Cement was replaced by up to 10% silica fume and 30% fly ash
water-to-binder ratio used in the mix ranged between 0.35 and 0.40.
superplasticizer was added in the range of 1 to 3%, by binder mass.
compressive strength increased by 3% when 20% dune sand was utilized, but decreased by an average of 3% for every additional 10% subsequently.
superplasticizer and higher water- to-binder ratio exhibited improved workability
replacing cement with silica fume and fly ash, the slump flow and pumpability increased
Compressive strength increased by an average of 4% for every 10% fly ash replacement. The incorporation of 10% silica fume improved the strength by an additional 14%
Lightweight foam concrete is common but to use it for 3d printing it would need to be extrudable. Extrudable lightweight foam concrete could be great for 3d printing because of its thermal insulation and accoustic qualities in addition to fireproofing.
The target dry density was 800kg/m^3 because that was figured to be the best balance between strength and staying lightweight. (9)
Structural fibers had a negligible effect on the mixes strength in tension, it is theorized that the fresh state properties of the material prevent the fibers to anchor in place which prevents tension strength (10)
As I mentioned, I will soon do a video on the support methods used for this type of construction. Another video on commercially available mixes for printed construction will probably be 3-6 months away as there are many solutions still in development that I would like to include.
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(1) Enhancing Buildability of 3D Printable Concrete by Spraying of Accelerating Admixture on Surface
Shantanu Bhattacherjee and Manu Santhanam Department of Civil Engineering, IIT Madras, Chennai 600036, India
3D Home Construction and InovaHouse3D have partnered up to build Brazils first 3D printed house in early July 2020. At 66sqm or 710 sqft it has 2 bedrooms and is currently being tested for its viability.
My name is Jarett Gross, I recently had the pleasure of speaking with Juliana Martinelli, founder of InovaHouse 3D and Andre Dantas, founder of 3D Home Construction. You can listen to the whole 100 minute conversation at the link above.
Printing the first house in Brazil was no easy feat but this team was able to achieve that lofty goal spending only $35,000 of their own money to develop the printer and print the house. This is a bootstrapped, grassroots startup driven by ambition and a dream.
The original printer developed by InovaHouse3D was given the friendly nickname ‘frankenstin’ because of the ‘use what you have’ nature of their project. With McGyver like resourcefulness they managed to demonstrate the viability of printed concrete on their custom machine.
Frankenstein helped push many of the early innovations and learning experiences for InovaHouse3D. Through their learning process they decided to build walls that are not connected by an interior support structure and don’t even use rebar.
The local municipalities often deal with many non-compliant construction projects done by the Brazilian citizens so maybe that is why they are willing to work with this company. InovaHouse3D is keeping the municipalities involved every step of the way. Fortunately, there is a precedent set there for concrete forms without rebar and by adhering to those standards the process is more simple than other countries with more strict building codes.
InovaHouse was built on the dream of affordable housing for the masses. This is a Brazilian company that is looking to make an impact in their home country and help their people improve living standards.
Now this company is raising money to print many more houses in a new location. The details of their next project have yet to be revealed but we can hope for as many as 10 houses on the next construction site near Brasilia, Brazil. The newest project will require around $250,000 in capital, interested investors should understand this is a long term investment in a new technology with a large reward potential when this tech becomes proven enough to be mainstream.
Last week I had the unique opportunity of attending the Digital Concrete 2020 event sponsored by Sika, Twente Additive Manufacturing, Weber Beamix, BEKAERT, Rilem, O-BASF, and DOW chemical. Every 2 years this event is held to highlight innovations in the future of concrete, generally it is an in person event however obviously this year it was moved online. In total there was over 1200 pages of research papers, over 100 presentations exclusive to attendees and 12 hours public YouTube footage.
From bridges to buildings construction techniques are evolving at a pace never seen before and considering construction is the biggest industry in the world, these changes will have significant effects related to efficiency, safety, sustainability, and affordable housing.
Engineering is complicated but anyone can understand the basics of printed concrete. All of these innovations fall into three important categories. Many topics discussed relate to the synergies between these categories but everything directly relates to at least one, Material, Printer, or Design.
People are experimenting with all kind of materials like dune sand, aircrete, dirt, salt, fly ash, metakaolin, Fe rich slag, and fibers like wollastonite fiber or polypropylene fiber.
There are many types of printers, most fall into the category of gantry style or robotic arm but many are a combination of both for maximum mobility.
There is much debate over the best method of reinforcing these large structures especially when trying to make them larger scale. Some companies have a mix that does not require post processing and others use rebar wire or screws to attain more structural integrity. There is also debate in onsite vs offsite printing and whether or not to use accelerant.
Design is a critical part of the process, without quality design the potential of these technologies would be squandered. The beautiful part is these technologies permit existing software for parametric design to be used to its full potential.
If you are interested in the future of construction then I would highly recommend attending the next Digital Concrete event in 2022 as I am sure there will be many significant developments in this field by then. I put together this video of highlights but it was very difficult to pick only 10 minutes from the 12 hours of event footage, you can watch the whole thing on the 3D Concrete Printing TUe YouTube page.
This is the one of the most cost effective and affordable solution for autonomous construction. Mud and straw has been used as a construction material for thousands of years but never like this. Could this be an early iteration of affordable housing that has 0 emissions? Creators Ronald Real and Virginia San Fratello said ‘On the 40th anniversary of the Smithsonian Magazine, they announced the 40 things you need to know about the next 40 years. Number one on that list was: “Sophisticated buildings will be made of mud”. Emerging Objects explores these frontiers of technology and material using traditional materials (clay, water, and wheat straw), to push the boundaries of sustainable and ecological construction in a two phase project that explores traditional clay craft at the scale of architecture and pottery. The end goal of this endeavor is to demonstrate that low-cost and low-labor construction that is accessible, economical and safe is possible. The project began in the contemporary borderlands along the Rio Grande watershed beginning in El Paso and Juarez and ended near the headwaters of the Rio Grande in Colorado’s San Luis Valley, which was the edge of the historic border between the U.S. and Mexico prior to 1848. The entire region has employed traditional pottery and earthen construction traditions for centuries.’
I had a great time speaking with Ian Comishin and Jonathan Ladouceur, the President and Head of Engineering from Twente Additive Manufacturing. In the very beginning of our discussion they even gave a quick virtual tour of their facility and showed a project that they were working on just minutes before our call. The tour uniquely includes a look at their 9-axis printer, many companies keep the details of their mechanical tech under wraps so it is great for people to be able to see what the large concrete printing apparatus looks like. We also get to see the beautiful surrounding Canadian landscapes and some other outdoor structures they have printed.
The project they are currently working on involves printing objects that have increasing vertical angles. They achieve this by increasing the height of the printed bead of concrete on the right side of the wall without increasing the width. Achieving a quality finish with so many variables at play is a challenge that they seem to have beaten. Twente additive manufacturing has consistently been pushing the limits of their print technology. They have even printed the formwork for the slab that they are now building a house on.
When asked where Ian sees Twente fitting into the 3CDP industry he said that he wants to help other people that need 3DCP tech figure out how to make it work best for them. For example, he is sitting on a staircase that he printed but if there was a company that specializes in staircases, he would be happy to get them set up with the tech to print custom staircases.
Ian and Jonathan were very transparent in discussing some of the challenges that they have faced in their projects. The two have been working on the same teams for many years at this point. They both seem to agree with me that 3D printed buildings should leave some of the exposed layers as a demonstration of the tech but there are many people that would prefer a smooth traditional looking finish.
About halfway through we get to talking about permitting and regulations. Currently printed elements can be used as a facade but not as the structural support of a building. In order for structural engineers to recognize the structural properties of a printed element they need to basically build 2 houses any time they want to print 1 because one house needs to be destroyed to demonstrate that it is strong enough to be valid. Of course every place will have different details and specifics when it comes to municipalities and regulations.
Down the line, Twente hopes to build the biggest printer in the world somewhere in Europe. Currently they are looking for partners or clients to help them achieve this goal over the next 18-24 months. Jonathan even specified that their printer will be able to print onsite and offsite. There are many was to segment companies in this sector and Twente does their best to fit into all of them, they use both gantry and robotic arm printers, single material and dual material printers, the list goes on.
I am sure we will see many more exciting developments in the 3DCP space from Twente Additive Manufacturing if you are interested in the details you can listen to the zoom call with the virtual tour that we recorded and put on YouTube.
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Many of you know Dubai is a hotspot for futuristic construction tech so it was great being able to speak to Luai Kurdi, the tech lead for printing concrete at Besix 3D. Besix 3D is a subsidiary of Besix which is quite an established construction company in Dubai. They have really demonstrated their dedication to automated construction technology by printing modular concrete pieces for the walls of an addition to their headquarters.
Luai was on the call with me from his apartment in Dubai where he had a beautiful view of the sea from his apartment in what seemed to be a skyscraper, you can see his view for yourself at 1:19:30 in the video.
As an architecture student Luai was always looking for new innovations and techniques for architecture even though his school primarily wanted to focus on teaching the old ways. It was on his own initiative that he learned about parametric design. Being skilled in parametric design, 3DCP became appealing to him because of the way the two subjects excel in collaboration.
A benefit of their technology is that it has the ability to operate while maintaining social distancing. This means that even in April and May of 2020 they were able to complete some prints without putting anyone in harms way.
In our lengthy discussion we touched on many topics like how the recycle any excess concrete, construction software of the future, heat resistance of printed concrete, concrete pumps, and much more.
Luai speaks enough languages to be considered a polyglot which is quite a feat, this helps him operate in a global environment and communicate better with more people. It is important that people interested in doing a project with Besix 3D have clear goals for what they would like to accomplish and at 1:41:00 you can hear about the typical issues with customer requests so that you can make appropriate considerations. Luai would like more engineers to enter the 3DCP space, the technology still has much progress to be made so it will require brainpower from engineers that will shape the future of contech to push to the next level.
Fernando de los rios may be the only person who has already worked at not one but two 3DCP startups. Many people have heard of Cazza construction but their project never came to fruition. Now Fernando is one of the founders of a company called Hyperion Robotics and they have a fully functioning concrete 3D printer.
We spoke about the printing process, how they build a pop-up factory around the print site to build on site occasionally and the concrete pumps they use. Hyperion uses a Kuka robotics arm as the foundation of their machine. They are working on some really cool projects that include artificial reefs and some exciting future builds that are still under wraps.
Fernandos startup experience extends beyond Hyperion Robotics and Cazza Construction, he also was a founder at a company called Prix (pronounced ‘pre’) that did grocery delivery. At Hyperion his primary responsibilities are on the business end rather than the hands on engineering but working in this high tech space he has certainly learned very much about the tech.
Hyperion is a company from Finland where they have a great startup environment to promote innovation and entrepreneurship. If you are interested in getting something printed you can go to https://www.hyperionrobotics.com/
After speaking with some startups about their progress in 3D printed concrete, I thought it would be great to speak with a bigger company with decades of experience in materials engineering about their perspective on future construction tech and I was not disappointed. Matthew Carli and I spoke for 2 hours on the subject and you can watch the whole thing below.
For those of you who prefer a synopsis, we first discussed Matthews role as Director of Innovation at Laticrete. Instead of resting on their laurels they constantly scope out the emerging technologies in their industry and have developed many iterations of printable concrete mixes that set quickly and yield very impressive strength results, thus how Laticrete fits into the 3DCP world. Some other areas Laticrete is demonstrating their forward thinking is their free E-Learning platform.
We also spoke about why 3DCP is not the solution to affordable housing yet and the key milestones to get there in the near future. Primarily, the current mixes are over engineered to get the best possible results far beyond the requirements set forward for concrete historically. To create a solution that will provide mass affordable housing, engineers will need to start focusing on making a cost effective product. More demand for this mix will decrease the cost inevitably.
We also talked about a really cool project that may be on the E-Learning platform soon which was converting a regular desktop 3d printer to facilitate concrete printing. When this becomes available I may try to convert my Prusa MK3 myself.
Then we got into parametric design. The more I learn about 3DCP the more I realize how valuable the relationship between 3DCP and parametric design is. I will certainly have to dive deeper into this topic in the future.
We spent a bit of time discussing the impacts of COVID-19 on Laticrete. In many areas construction has been permitted at this point so Laticrete is certainly still very much in business, but COVID has transformed the way business is done. Everyone is pretty much working from home using Microsoft teams to collaborate and get their work done. Matthew said that Laticrete was able to adapt to this situation without halting too much of their productive activities.
I look forward to seeing how Laticretes developments contribute to the 3DCP space in the future, you can expect them to continue experimenting with printable fast set concrete and are already cementing themselves as a leader in construction materials.
First I would like to thank Volker Ruitinga for taking a leap of faith in permitting me to record this discussion even though it is the first long-form discussion that I have posted publicly.
Volker is the founder of Vertico, a startup in the Netherlands that uses a large robotic arm to 3D print in concrete. As you could imagine with a focus like that they have many interesting projects. They’ve printed concrete canoes, benches, vases, and have an exciting upcoming project to build a house, but many of the details on that are still under wraps.
Even though Volker did not major in engineering in university, he discovered an intrigue for 3d printing when he helped facilitate the sale of a robotic arm from an automobile manufacturer he worked for to a company interested in using the robotic arm for 3D printing. His initial interest in large scale printing was with plastics but since then he has switched to concrete, finding it to be more practical.
There were two major takeaways for me in this conversation, the importance of a quality concrete mixing pump, and the promising future of parametric design.
Vertico is on their second version of their printer, a change they made to increase the build size the machine is capable of. The extruder portion of the printer has been updated many times and now they are using a multi material extruder in order to make their process more effective. Volker made it clear that the pump was a challenge for them at one point, the commercial pumps available to them at the time were not sufficient for this application so Vertico was forced to design their own smart-pump that includes more control over the flow and speed of the pump. By using their custom pump they are able to switch between different concrete mixes seamlessly.
Vertico is not just a hardware company, the software feats they are accomplishing are equally important but it is hard for people to see the software advancements going on behind the scenes to make the builds you see possible. Volker ran a hackathon in order to build an open source code for slicing stl files into printable gcode that is available for free to anyone wanting a place to start with 3D printing in concrete.
At this time, Vertico is selective on what they focus on and choose to be experts in hardware, pumps, and software. They have chosen not to focus on materials and permitting yet but they keep a keen eye on the developments that organizations are making in this sector.
Like most companies in the emerging sector of 3DCP, Vertico is a developing startup and their pace of progress is rapid because they are agile. It will be very exciting to see the progress that they make in the future.
Check out the full 1hr 20 minute conversation at the link below.
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Printers designed in Russia, headquartered in the united states. Many projects including placing in multiple rounds of the Nasa space 3d printing competition and a very large office building in Dubai.
3d printer company that developed a large 3d printer called the Delta Big. They are capable in printing many materials including a simple mixture of dirt and straw that is extremely affordable and good for the environment.
The bod 2 printer is quite an advanced gantry system. Cobod has the intention of doing module 3d printed construction. They are a one of the market leaders in Europe.
Constructions 3D has a robotic arm printer that resembles a boon. It stands uniquely like a spider and is capable of printing in quite a large radius.
Icon is an American company that has partnered with a non-profit new story to print an affordable housing project in south America. They have also partnered with some united states government programs in Texas
Contour crafting is an American company that has partnered with the united states department of defense for emergency relief applications. They are a sleeper pick in the industry, I think that because of their government relationship they are not allowed to share much intel related to their projects.
Mudbots sells the cheapest printer of all the companies on this list. You can buy their printer online for around $30,000.
Rohaco/ swinburne university
6 axis printer designed in collaboration with Swinburne University.
6 axis printer allows them to print forms on surfaces that are not flat. This increases the flexibility for designers and architects who want to push the limits of this new tech.
Claims to be 3D printed but I am unsure what part of their design is supposed to be printed.
Cerambot is a company that has focused on building 3d printers that print in clay and ceramics but they have developed a large scale model capable of printing in concrete.
This company is only a concept and they have not given any updates in years but their idea was so unique I had to share it. Koala 3D wanted to have many robots in a swarm doing construction together.
This project was to 3D print a small house from plastic. It seems like it was either a temporary installment of just a rendering.
Sika is the biggest company on this list to publicly demonstrate a big interest in 3d printed construction.
Unique looking outdoor structures and shapes very large and artsy, Design focused.
Many international projects printing houses
Design and 3D printing services for custom construction elements such as columns, beams, slabs and walls.
Determines printability of a model by analysing structural properties.
Twente Additive Manufacting
Medium to large building components like steps or intricate window designs
Biggest 3d printed house in America
Chinese company that has received over $200 million in investment. They have done many projects but do not have the most advanced technology especially considering the total investment.
Prints square walls
Enrico Dini was the first person to ever 3D print a house in concrete.
Printed a bridge in metal
Prints small parts of buildings as a subcontractor rather than trying to build the entire thing at once.
European space agency did a project with Foster & partners to make this rendering of what a 3d printed moon base could look like.
Andrey Rudenko took the world by storm when he build a 3D printed concrete castle in his own backyard. This impressive project went viral.
Foam outline that gets concrete poured into it
French company with a printer
Conveyor belt system from a boon to pick and place individual bricks
African Company that printed a circular structure with interior supports
Cheapest Printer on market has a medium y and z axis print area but the x axis seems to only be about a foot in their cheapest model.
Used Cobod printer for bod project
Shotcrete extruded onto premade dome, hard to fit into the 3D printing category
Tera concept for earth and also printed mars habitat concepts
Patent on membrane between layers and wall stack system
Prints smaller wall segments then moves printer to print the next one.
Larger company demonstrating an interest in 3D printing
Large retrofit to revitalize building
Unique printer head group of students
Small printed letters high accuracy
Dubox & Witeeven + Bos
Demonstration print witeeven + bos is involved in many other 3d printed projects as well a
Unique automated system tying rebar
Robotic arm maybe on a track
Small scale print proprietary solution
Studying the future of geopolymer concrete better fire resistance
Imprimere AG Big 3D Printer
Round print suspiciously little footage
Construction company experimenting with the tech
Unique mixture to print that has different properties that concrete making it better for printing
Big robotics company that makes many of the robotic arm printers
Large scale PLA projects like this chair. Companies like this will
Large outdoor features
University project using gantry style rohaco instead of the robotic arm rohaco that youve seen earlier.
Small 3d printed parts assembled by hand into a larger project
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Like a car has quantifiable specifications like 0 to 60 speed, horsepower or breaking speed, and qualitative qualities like comfort and styling as do different models of 3-D printers in construction. First let’s discuss the quantitative traits. One of the most important factors is how big of a structure can the 3-D printer create. Some companies like Winsun from China have massive 3-D printers in a warehouse that do not move. Although they are immobile and unable to print on site these printers can be over 10,000 ft.² in base area and over 30 feet in height. Other printers like the one developed by icon build have systems on rails that permit axis of unlimited length.
Another quantifiable measure is print speed. This factor is effected by the size and shape of the nozzle extruding the material you’re printing with. If the material you are printing with takes too long to dry then no matter how fast your printer is able to move you will still need to wait until the last layer is structurally secure enough to print the next layer on.A majority of these 3-D printers are meant to be mobile so that they can print on site. This makes the weight of the printer another important factor. The heavier and larger the printer is in its disassembled form the more expensive it will be to transport driving up costs of the construction project. Very few companies have yet to develop tremendous solutions for value engineering the transportation cost of their printer.
The industry is so young that most companies are still perfecting the reliability and print quality of their machines.Energy required to operate the printer it Is also an important factor. Both from a cost and environmental standpoint it is important.Now on to the qualitative aspects. There are many different styles of 3-D printer as discussed earlier a big differentiation is whether they operated on polar or Cartesian coordinates. Polar coordinates are optimal for creating smooth lines where as Cartesian coordinates make it easier to create sharp edges although both styles of printer are capable of doing both of those things. Generally a printer operating on Cartesian coordinates will be a gantry style printer with four pillars although some operate on as few as two with a rail system or six or more without the rail system.
The next qualitative aspect is mobility. Is the printer is intended to move, or is it meant to print everything in one location and the things it prints be moved after the fact? If the printer is mobile, must be disassembled and assembled between each project? Often time’s printers on polar coordinates are easier to transport because they operate off of one peace and robotic arm as opposed to an entire gantry system. It is much easier to stabilize the nozzle with a gantry style printer because there are so many more supports. It is challenging and very expensive to create large-scale robotic arms capable of millimeter precision, especially when the robotic arm must carry a heavy load like a metal nozzle and large hose full of heavy liquid concrete mix.The form of energy that the printer runs on varies. Some printers operate on liquid gas where as other printers operate on electricity. Electricity tends to be more efficient, however in some regions electricity is not readily accessible. Wasp 3-D claims to have achieved 3D printed houses using electricity generated from solar panels.
As this technology improves it will be interesting to see the development of these printers. Currently most are made from metals like steel.There aren’t many companies competing in this very young industry. These printers require significant investment to develop and we will not likely see them being mass-produced any time soon. It would be very challenging for one company to quickly capture the entire market simply because the construction industry is such an enormous beast. There are many enormous construction companies in the United States and many thousands more that operate as small businesses on more local scales.This technology will open up the doors for all kinds of new businesses in the construction industry.
The biggest issue with the 3-D printed construction market right now is regulation. Enormous unions that are stuck in old ways have had influence over construction standards and regulations in America over the past two decades. There has yet to be a legally permitted residence 3-D printed in America. However there are other countries with fewer regulatory hurdles that have already 3-D printed structures completed with people living in them currently. Most notably a project done by Icon Build and New Story in Ecuador. These strict regulations could take decades to change, that is why the cost of the specialized concrete needs to go down so that the technology can be a significant enough improvement to convince legal officials to permit 3-D printed construction.
If all goes well it could be a matter of a few years until it is evident these structures are strong and safe enough to allow humans to live in them.The best markets for 3-D printing construction are southern areas where the temperature rarely goes below freezing. If the temperature rarely goes below freezing then it is not necessary to pour extremely deep concrete or drill down to the bedrock in order to have a structurally secure building. If the leaders of your municipalities in states like Texas or Florida want to champion this technology there is certainly that opportunity. It is likely that the first region to adapt this technology wilI have an economic boom with the quantity of high-quality unique affordable housing that this technology has to offer.
In some countries in Europe, plans are already underway to build complete 3-D printed villages. These towns are a very exciting opportunity for this technology to demonstrate its practicality.The people who need this technology most are people in impoverished countries. Unfortunately those countries are often the last to receive the benefits of new innovations. It is challenging to do even nonprofit projects in these regions because often times the government officials or imposters are so corrupt that they expect to be paid to allow you to do charity work uplifting their communities. If not the government, there are often rogue rebel groups that will cause issues and delay if not stop completely your progress and mission. Without a seasoned overseas non-profit veteran on the team it is a dangerous and treacherous and environment to pursue. In my opinion the best way to make this technology mainstream is for the current companies that have built printers to focus on printing things that don’t require complicated permits. Many products come to thought, you could build a fireplace, a bench, a fountain or other water feature, a planter wall, a retaining wall, highway barriers, a shed, an outdoor standalone garage, the list goes on and on.
If companies can produce these products to be attractive to consumers from both a quality and cost standpoint then it could be the optimal way to introduce the public to this technology of the future and get them comfortable with it so that when the time comes that these robots are building their new home they feel safe and excited to moving.As this technology improves new ideas constantly come along for applications that drastically improve the efficiency compared to traditional construction methods.
Concrete is not the only material that people have been considering 3-D printing construction with. A company that goes by the name MX3D has developed a printer that is capable in printing large metal structures from a single robotic arm operating on polar coordinates. This company is based in Europe and has already demonstrated the viability and practicality of their printer by building a bridge over running water using their 3-D printer. The bridge is made completely out of metal and is strong enough to be driven over by cars. Printing in metal is a very exciting possibility for the future of automated construction.A big part of what makes metal so great for construction applications is that unlike concrete the metal hardens almost instantly therefore be printed in a horizontal line with no supports whatsoever. This unique feature and capability opens up a whole new realm of possibilities not just for the construction industry but 3-D printing as a whole.Although many homes are now built in concrete, especially in hot southern regions like Florida or Texas, there are some people who do not like the aesthetic of concrete. These people would prefer not to live in a concrete home even if the price is significantly cheaper. That is what makes the Swedish 3-D printing +project called so unique (1) this company is working on printing in cellulose.
Cellulose is considered a bio plastic it has strong insulating features and so unlike metal or concrete it is not cold to the touch in cold weather or hot to the touch in hot weather. Cellulose is actually what wood is made out of. Walls printed in cellulose would be far more comfortable feeling then one printed in cold concrete. The trick to printing in cellulose is mixing it with acetone. When the cellulose mixes with acetone it becomes liquefied and can then be printed. After the mixture of acetone and cellulose has come out of the printer the acetone quickly dissolves and evaporates into the air leaving you with just the solid cellulose. This technology has very exciting potential although judging by the progress that has been made thus far it is significantly more challenging to print with and more expensive than it’s concrete counterparts. There is also the slight risk that acetone could get on your home and melt it causing significant and potentially life-threatening damage however that is unlikely as acetone rarely if ever occurs in nature.
A big company called SOM has 3-D printed small office pods using plastic polymers. These polymers are weatherproof and the design of the office pods is quite aesthetic and modern. They are one of the few larger construction companies that have publicly demonstrated investments in 3-D construction technologies. It is very likely that in upcoming years large companies will pour more money into these types of products.It would be wise of construction equipment manufacturers like Caterpillar and John Deere to invest in these technologies to some degree as a 3-D printer capable of building a house could eliminate the need for many John deer or Catapillar products. It is likely that they could reach a Kodak like fate holding on to a dying technology until their last breath, as new comers in the industry takeover from incumbent giants the way digital photo technology and social media look over the photo and video capture industry. Kodak specialized in film and when the time came to adapt they failed. New technologies are an early warning to large equipment manufacturing companies to take automated construction technologies into the utmost consideration and monitor closely the progress of their peers.
NASA is holding a 3-D printer construction competition for applications in outer space specifically on Mars. Apis Cor has won in various segments of this competition. There are many other companies competing in this NASA Space construction competition yet Apis Cor continues to stand out among the crowd. Construction on Mars comes with its own set of challenges. The atmosphere of Mars is less protective from radiation in the atmosphere on earth. This means that in order to ensure the safety of a human being on Mars a building will need to shield the people inside from the radiation in the external environment. This also means that the buildings will need to be perfectly airtight if the outer shell is permeable then the structure will not be safe to inhabit on mars.
Another massive consideration when contemplating construction on Mars is the material that you will build with. Due to the astronomical costs of sending things in this space per pound, it would be extremely costly to ship in all of the building materials. It is likely that initial structures will have material shipped in but in order to sustainably build on Mars we will need to come up with material solutions that are made from Mars’s natural soil. This natural soil on Mars is called regolith. Regolith is made up of a variety of metals and other elements that can absolutely be used in construction. It has been hypothesized by Universities that regolith can be heated up to temperatures around 3500°C in order to burn off excess elements and leave only the strong building materials. Regolith is abundantly available on Mars so if we are able to team the soil on the planet of Mars into a practical construction material it will get us one step closer to establishing a human colony on what was once thought as an uninhabitable planet
Currently there are many databases that contain STL files with the intention of being shared and printed. Website like thingiverse.com have thousands and thousands of models that you can simply download for free and print. On these websites you can find a wide variety of things ranging from small tools like a wrench or scissors to toys or other useful knickknacks. Every day people are adding more and more STL files to websites like thingiverse and as the community grows the quality and quantity of content and practical creations is increasing.
I envision future software for 3-D printed construction that is the one stop shop for all of your construction needs. This software will contain a seemingly limitless number of models that can be 3-D printed in the concrete. There will be models ranging from fireplaces and fountains to homes, stores and office spaces. People will be able to browse through these models, purchase them and have them printed in under a months time for cheaper than previously imaginable. This website or application will also include an editor feature. This editor will allow you to modify existing designs to your liking or create your very own from scratch. This is much easier said than done because there are some limitations to 3-D printing in concrete, the largest of which being that you cannot print in midair. Concrete must be laid on top of something or else it will simply fall to the ground. It is very likely that some architects will fight to keep this software from becoming a reality.
If you can create a software that guarantees structural security of a building then you largely eliminate the need have an architect at all. Software like this will empower the average person with the ability design a home to their exact liking and customization.
Preceded only by water and food in Maslow’s hierarchy of needs, shelter is one of the most important attributes in the pursuit of content for mankind. Every human being requires some form of shelter and there is a huge disparity in shelters quality and amenities comparing upper class Americans to developing nations who shelters are often made of scrap materials or dirt and straw.The construction industry is one of the oldest industries. It came before the written word and most ancient art and relics come in the form of architecture from different empires. Egyptians, Greeks, Romans, Aztecs, and many more ancient civilizations all left behind unique architecture that cemented their place in history as powerful world leaders.
Innovation is happening today at a rate we have never before witnessed in history. Our constant improvement of computing technology and our ability to analyze data has given us access to information we never had before. The ability to share that data and content with anybody connected to the Internet has changed nearly every industry that operates in a competitive capitalist market.
Think of the way Uber changed the taxi industry, or the way Apple changed the cell phone industry implementing an app store that granting nearly limitless potential to application developers went on to create $1 billion company all inside of the infrastructure of Apple’s App Store. The food industry has also been drastically changed. For the first time in history people are spending more money on the prepared food and beverages that groceries, eating food from restaurants rather than cooking at home. What caused this paradigm shift from making food yourself to ordering it, whether it be at a restaurant or via delivery service. Efficiency is the main driver of our innovation in all of these industries and technology is fuel of that innovation.How is it that the construction industry, one of the most necessary and everlasting industries has been so stagnant? When you examine the recent innovations in the construction industry almost all of them revolve around software. Software developments help people working on construction projects go through building drawings and spec sheets on a computer. BIM software helps you to visualize the construction of the building people have created robots that can give you a 3-D map of the interior and exterior of your building just by driving through the building. The other big segment of software that innovative construction was scheduling software.
Many like to playfully scoff at millennial’s for living with their parents even when many of them have achieved jobs that afford them a moderate lifestyle young people are having a hard time buying homes or are choosing not to, likely because the cost is so high. the number of years it takes to save up for the down payment on home on average is higher than its historically been. (1)(2)
Overseas, there are many regions that are severely and disproportionately impoverished in comparison to the rest of the world. Over 3 billion people live on less than $2.50 a day (3). For some cultures this is a lifestyle choice for others they do not see a clear path to a better lifestyle although they would give almost anything for the opportunity to improve their living conditions and well-being.
The biggest innovation in construction of modern history was the skyscraper and although people continue building to new heights there is no tremendous world changing value in building skyscrapers that are 100+ stories.What the construction industry needs is a paradigm shift to automation in the pursuit of efficiency.
WASP (World’s Advanced Saving Project) was founded in 2012 by its founder, Massimo Moretti, as a source of the CSP (Centro Sviluppo Progetti) company founded in 2003. The company is located in the city of Massa Lombarda near Bologna, Italy. WASP currently exists. of approx. 20 full-time employees and approx. 10 people working freelance. Of these, 4 people are employed to do R&D. They currently have reportedly a healthy and relatively steep growth curve. WASP develops innovative projects in a wide range of areas and has used 3D printers in almost every context as a way to achieve its goal. WASP generally has a vision of doing everything they can to save the world and is constantly using this vision to show the way in which new projects they will work on. Thus, WASP does not develop 3D printers for sale, but develops 3D printers to address specific needs to achieve their goals (saving the world). For all their purposes, they use the same types of 3D printer, where they then change the print head depending on the material they want to print with. Their printing method is called Delta printers, where the printer is controlled by three arms mounted on three vertical columns. The arms can then move up and down the columns depending on which direction the printer should move
The vision is to save the world and the way to do this is to fill a container with equipment for a 3D printer. The equipment must be so easy to handle that it can be done by a person from the third world without the person having any training. Using the 3D printer, you can make advanced equipment where the only thing the person (s) must do is feed the printer with printer material. Examples of items that the printer needs to make are medical equipment, chairs, tables and buildings / cabins. WASP focuses on Maker’s economy1, ie. focus on the use of local materials and in-house production. Consequently, there is no transport costs and thereby a reduction in CO2 consumption.
WASP has initiated many different development projects and has made them develop printers that can print in the following materials: – Plastics (dentures, chairs, tables, visualizations of products, etc.) – Ceramics (art, etc.) – Silicone (medical equipment, dentures, soles, etc.) – Smiles (goal: cabins) – Concrete (target: cabins) A few examples of their development projects are listed below:
1.2.1 Medical equipment (dentures, corsages, etc.): 1 http://www.wasproject.it/w/en/maker-economy/ 3D Printers – State of the art Page 4 of 15 1.2.2 Plant cellar: Prototype of 3m tall plant basin where all the plants are watered from above and all the water runs through. 1.2.3 Toy printers (for teaching and play) 3D Printers – State of the Art Page 5 of 15 1.2.4 Chairs and tables 1.2.5 Plaster and ceramics (art, etc.) 3D Printers – State of the Art Page 6 of 15 1.2.6 Clay hut or concrete hut WASP wants to be able to print clay huts or concrete huts to provide shelter for people in the third world and therefore they have launched the BIG Delta WASP project, where they will print on a large scale and with clay or concrete,
The company is 100% self-financing and finances their business through the sale of their 3D printers and WASP is experiencing great growth in sales of their 3D printers. In 2015, they sold approx. 1500 printers.
The technology / printer WASP generally uses a printer technology they call Delta. It is therefore the same principle they use for their large and “small” printers. It consists of 3 vertical columns which are placed on the radius of a circle and which have an angle of 120 degrees. Up and down of these vertical columns is mounted an arm which is connected to the printhead, which is basically located in the center of the circle. By moving the arms up and down, the print head can move in different directions and the three arms are coordinated so that the direction in X, Y and Z direction is completely controlled. Due to the sloping arms, some of the vibrations from the movement of the printer will be transformed into vertical movements and therefore WASP states that this technology can provide greater precision of the print than traditional “horizontal” printers. 2.1.1 Small Delta WASP The Small Delta WASP produces the fastest plastic printers on the market and can print up to 1000mm / s, which is 3 times faster than other printers. Massimo further indicated that they were aiming to double this rate over the next year. Another characteristic of their small printers (which are very sensitive to vibration due to the high speed) is that the extruder head is placed in elastics above the actual printer and therefore the weight of this extruder does not affect the vibrations in the printhead. The printers can print in layer thicknesses from 50 microns to 2-3mm for plastic printing. 2.1.2 BIG Delta WASP2 BIG Delta WASP is WASP’s large-scale print project in buildings / cabins. As previously described, WASP has a goal of being able to print buildings / cabins for groups in the third world. BIG Delta WASP has already held an event where they have set up a 12m high printer. This took place from 18-20. September 2015 in their hometown of Massa Lombarda.
WASP has orally been awarded a field by the mayor of the city where they can set up their BIG Delta printer. When we visited them on April 6, 2016, this was not approved in writing, so they were still waiting to be able to set up the printer again. We saw the printer in its packed form. We also saw their print head incl. container, mixer auger and auger rotor machine. Massimo’s experience with print with concrete was that it was of utmost importance that the concrete was constantly moving (brought forward). You cannot have a mix that is still in the container. That’s why he has good experiences with an open auger. The principle of supplying material is that the container is fed with material via a pump which is on the ground. 3D Printers – State of the Art Page 9 of 15 the outside printer and pump are fed with material from 2 pcs. concrete containers in the traditional way. Massimo told that the scaffold as their printer one is made of is very stable and it is actually not necessary to stiffen the system of bar stools. In addition, he indicated that the size of the printer is scalable, as the scaffold can only be increased or decreased as needed. Due to the very limited time in which they have actually had the printer standing, only very small items have been printed so far. In the coming future, when the printer is standing permanently, they will most likely gain a lot more experience with the printer and with large-scale printing. 126.96.36.199 BIG Delta WASP (scaled down) To gain experience with the clay and concrete materials, BIG Delta WASP has set up a smaller “large-scale” printer, see image below. This printer can print objects of approx. 1m in diameter and 1m in height.
WASP already had good experiences with printing in concrete and they did not think it was a problem to mix a concrete that had the right density / viscosity, so that the material could be fed into the printer and at the same time, so it had a suitable hardness for the layers did not settle (the lower layers float out when the above layers add extra weight to them). Their experience was that preferably between 10-30 minutes should pass between each layer in order for the above relationship to be achieved. If there was more than 30 minutes, it was possible that there was no suitable connection between the layers (layering). Their experience was that it may be a problem for 10min between each layer to print small objects, but it should not be a problem for large objects and you rarely achieve more than 30 minutes. Massimo stated that he did not think there was a major problem in making a concrete that had the desired properties. They had not done pressure testing of the concrete yet, but had achieved a fine structure and bonding with the concrete they have used in the above pictures (though very fine grained concrete). They also had good experiences with printing clay. However, the WASP had faced some challenges in printing concrete containing Geopolymers3 instead of cement, but he thought they were quite far around this. By printing with geopolymers, the building’s CO2 footprint is reduced by approx. 80% compared to traditional cement based concrete. Massimo showed a piece of concrete made with geopolymers, see the picture below:
In August 2015, WASP completed its first major project with a concrete printer, namely a concrete beam cast in seven smaller sections, which are then subsequently assembled into one beam via reinforcing iron. The beam has been primarily used to test the 3D concrete prints principles. In September 2015, for the first time, WASP erected its 12m high concrete printer at a 3 day event where the printer was primarily shown and very small concrete castings were cast. The event was primarily a PR event. In the future, WASP wants to build housing for third world countries in local materials.
Established in 2002, WinSun is a high-tech company that researches and develops new materials and production methods for construction, including 3D printers. WinSun today has approx. 200 employees and 98 national patents (in China). Of the 200 employees, approx. 60 people with project management and only 2 people work with R&D. WinSun has no designers / architects employed. WinSun is headquartered in Suzhou district approx. 100km northwest of Shanghai. They once had 4 production halls, but have scaled this down to 2 production halls. One is located at the head office near Shanghai and the other is in the middle of China.
1.1 History In short, WinSun’s 14-year history (primarily according to WinSun’s website). See explanations for products under section 2: – 2002: – 2002-2003: – 2003-2004: – 2004-2005: – 2006: – 2007: – 2008: – 2012: – 2014: – 2015: – 2016: WinSun startups WinSun develops the product GRG (Specifically fiberglass reinforced plasterboard), as the first company in China. WinSun is changing GRG’s production mode from manual art to fully automated continuous production. WinSun develops a print head and an automatic feeding system, which increases production efficiency by a factor of 10. At the same time, it created an opportunity to recycle industrial waste to GRG production. The production method for GRG production has been continuously improved up to date. WinSun develops the product SRC (Special Reinforced Concrete, Special Reinforced Concrete) using a combination of CNC automated technology, 3D printing technology and fiber reinforcement technology. WinSun develops the CMS (Crazy Magic Stone) product. WinSun is making the first 3D printed building. WinSun completes the technical system / design in order to 3D print buildings. WinSun prints as the first company in the world 10 houses in 24 hours. WinSun prints a 6 story residential property. WinSun prints office building for Dubai1 In 2015, an article was published that questioned the above story and the company’s working methods, and which, among other things, accused WinSun of cheating on knowledge. 2 1 https://ing.dk/artikel/se-dubais-3d-printede-fremtidskontor-blive-bygget-184518 2 https://3dprint.com/57764/winsun-3d-print-fake/
The vision is to expand production to the whole of China as well as internationally. Internationally, this must be done through partners. WinSun will change its production form from large and immobile Gantry printers to small flexible robot arm printers. To reduce transport costs (both economically and environmentally), the vision is to have these small mobile printers located around China, with a maximum of 300km to any construction site.
1.3 Financing The back man behind WinSun is Mr. Ma and he succeeded in finding investors who will invest in two production halls. WinSun is expanding internationally through partnerships where they deliver the printer and get Royalty Fees for the items produced.
WinSun has developed 4 different materials / printer technologies to build different products. They produce everything from the load-bearing system (concrete walls) to the cladding of the walls (plaster) and the interior (furniture). In the following, the 4 printers are briefly mentioned, but with special focus on the concrete printer. 2.1 Other Printers In addition to a 3D concrete printer, WinSun has built 4 other printers that are used for various products. The other printers are described in the following, however, this has been made very brief as it is the concrete printer that is interested in this report. During the visit we were not aware of how the following printers were constructed, so in the following only some illustrations of objects that they have printed with the individual printers are shown. It should be noted that the following is not something we inspected during our visit to WinSun, as we were not allowed to see the production facility, but are mainly excerpts from their website. 2.1.1 GRG (Glass Reinforced Gypsum, fiberglass reinforced plaster) The GRG printer makes objects in fiberglass reinforced plaster. The material can be molded into many different artistic forms and is often used to coat the surfaces of large rooms with high acoustic and aesthetic requirements, such as theaters and concert halls. The following is an example of objects printed with the printer. Guangzhou Opera House:
2.1.2 FRP (Fiber Reinforced Plastic, fiberglass reinforced plastic) The FRP printer makes fiberglass-reinforced plastic objects. The material can be formed in many shapes and has a high strength. The printer is used to make furniture and below are some examples of objects made in the printer. Table from WinSun’s showroom (seen during the visit): Other examples of printed objects from the WinSun website. 3D Printers – State of the Art Page 7 of 34 2.1.3 CMS (Crazy Magic Stone, fiberglass reinforced artificial stone) The CMS printer makes objects in a new type of artificial stone material. The material is called Crazy Magic Stone and is made of specially treated quartz sand added to special fibers to increase the strength. The printer is used to make interior and exterior floors, walls and roofs. According to WinSun’s statements, they can produce 10,000m2 a day on their production line. A few examples from the WinSun homepage on objects created by the printer are shown below. Shanghai Mann Tea Garden Villa: Phoenix International Media Center: 3D Printers – State of the Art Page 8 of 34 2.1.4 SRC (Special Reinforced Concrete, special reinforced concrete) The SRC printer makes objects in special reinforced concrete that are mainly used for facade cladding. The facades can be made in a myriad of colors and on three different surfaces (smooth / smooth, velvet / velvet and lychee). The following is an example of objects from the printer: Beijing Strawberry Mansion:
2.2 Concrete printer WinSun has developed a large Gantry printer which they have located in their production halls (one hall at the headquarters near Shanghai and one hall in the middle of China). The printer has a dimension of 150m x 14m x 8m and this is WinSun’s second generation of their printer. They are currently. developing their third generation printer. We were not allowed to inspect the printer during the visit, but have seen a number of buildings they have made with it, see sections 3 and 4. The printer is primarily used to produce items which are then assembled in the space. Ie they did not create a large printer to print in large dimensions (large elements) but to optimize their production. Thus, they produce smaller concrete elements throughout the length of the printer, but the elements are no larger than they can be transported on a truck. Thus, this production is very similar to the production in Denmark with large halls where concrete elements are produced. It was stated that the printer was to be operated by only one man. He was able to control both the computer and the printer, as well as apply reinforcement as the layers were printed. The concrete printer can only print vertically. This means that the printer cannot place a layer slightly skewed on the previous layer, allowing walls to rotate or give unique shapes. This means that the printer is limited in its architectural expression, since, for example, you will not be able to make a column that rotates about its vertical axis (dispute), see example from the USA where this is done below.
Photo: Lewis Yakich’s Hotel in the Philippines. Listed by Andrey Rudenko. Example of a 3D printed column that rotates about its vertical axis. 3D Printers – State of the Art Page 10 of 34 It was stated that the printer has a capacity of 500,000m2 per year of a standard wall with a thickness of 240mm, as shown in the image below. Calculation of printer capacity: Prerequisites: Illuminated capacity of concrete printers: 500,000 sqm wall with a thickness of 240mm Production period: 300 days per year and 24 hours a day. 500,000 sqm / (300 * 24 hours) = 69 sqm / hour Width of track / track: = 40mm Layer thickness (layer height): 15mm-19mm -> Average 17mm -> 58.8 layers per m (vertical) Length of tracks on 1m wall (horizontal – laying of 1 layer of concrete): Pages: diagonal: Total: Calculation: Total length of lanes of 1m2 wall Total concrete volume of 1m2 wall Printer speed: Volume of concrete prints = 2 * 1000mm = = = 2000mm = 1350mm = 3350mm = 3350mm * 58.8 layers = 197m * 0.04m * 0.017m = 197m / sqm * 69kvm / hour = 0.134m3 / sqm * 69kvm / hour = 197m / sqm = 0.134m3 / sqm = 13593m / hour = 3.8m / s = 9.25m3 / hour = 9250L / hour The speed of the printer seems unrealistically fast and the volume also seems unrealistically high. In comparison, the printer in Russia could print 162L / hour, ie approx. 60 times less. 3D Printers – State of the Art Page 11 of 34 3 BUILDING SYSTEM WinSun has developed a building system for the construction of raw houses based on 3D printing. The following is a review of WinSun’s construction system and some comments are made on where the considerations will have challenges with a Danish norm system, where the requirements for documentation in practice are probably somewhat more extensive. 3.1 Walls The following are the considerations made in connection with the walls.
3.1.1 Vertical carrying capacity The walls are typically made in a total thickness of 240mm, with each side being approx. 40mm thick and the sides are then joined by diagonals (also 40mm thick). The diagonals are introduced to support the wall to achieve a much larger column capacity (load-bearing capacity). The diagonals typically have an angle of approx. 45 degrees relative to the sides and therefore they will stiffen one wall page per second. ca. 320mm. The thin wall sides of 40mm will thus avoid folding and can be designed to take up a large printing capacity. This however, provided the diagonals and sides have sufficient interaction (including the tensile capacity of the concrete). Manually horizontal reinforcing irons are inserted between some of the layers at a vertical distance as determined by the design / structural engineer. However, one may be concerned about whether the reinforcement is active in all cases, since the reinforcement is not always in the concrete, but only along the sides, see the picture below (not directly in contact with the concrete). The fluctuating quality of performance will also present some challenges in relation to Danish norms. 3D Printers – State of the Art Page 12 of 34 The walls will, with the above design / stiffening with diagonals) have a capacity which (in isolation) can carry smaller buildings (expected: 3-4 floors, depending on the compressive strength of the concrete), but it will not be sufficient to execute tall buildings (many floors). The wall must be considered unarmed and it is most likely to cause major problems to get the design approved for Danish norms, see among other comments below on horizontal castings. For tall buildings, zones are introduced between the walls, which are cast after the wall is installed and where traditional pillar reinforcement is introduced. In this way, tall buildings will carry their own weight point-wise via reinforced columns which are inserted into the wall at a distance according to the design. It is therefore not computationally the 3D printed wall that carries the load in tall buildings (in practice they will carry much of the load), but the subsequent in-situ molded columns. It was not disclosed and it was also not possible to see inside the wall of the building with 5 floors whether or not pillar reinforcement was introduced into the walls. WinSun stated that they are currently is working on a 3D printed building at a height of 100m (about 25-30 floors) and this should use the above method with in-situ molded reinforced columns inside the walls.
3.1.2 Casting threshold (coherence between elements) The walls are delivered in wall elements which have an extent that corresponds to what is space for one truck. The individual wall elements are reinforced together by shackles protruding from the end of the wall. 3D Printers – State of the Art Page 13 of 34 ment. The collections are cast afterwards, see the pictures below. The walls are often carried out at a height of 1-2 meters and then stacked on top of each other. No overflow is carried out and the horizontal castings are made so that the concrete elements are crushed on each other. According to Danish norms, this practice will not be feasible, as no normal force will be transferred between the walls (or very little). There is no knowledge of the interface between the two elements. To give some vertical cohesion, zones are introduced where a threaded rod / coupling can provide vertical cohesion between two wall elements. The coupling is introduced at the factory by casting between two diagonals and one side (a triangle) and inserting a coupling. This coupling can then be used to provide a tensile anchorage between two wall elements. Nothing was clarified about how the forces spread into the wall. They also use the clutch to lift the element.
3.1.3 Doors and window openings When WinSun produces door sills and window openings, they place a wooden board in the doorway on which the printer can print, see the image below. The plate can be removed after casting if there is sufficient reinforcement to absorb the draft. However, it will require some deformation of the bar to activate the reinforcement and therefore some cracks are expected. The method of casting over door beams is the same as for the other walls, but with extra horizontal reinforcement in the wall. There are several examples, see the pictures below, that there are clear cracks in the overlap. This may be due both to the fact that the reinforcement does not lie in the concrete layer, but within the layer and thereby is not active or as mentioned above, that some deformation needs to take place for the reinforcement to become active when the wooden board is removed. 3D Printers – State of the Art Page 15 of 34 3.1.4 Stability (absorption of horizontal forces / disc forces) No method of incorporating horizontal forces / slicing forces into the walls was specified. Since no significant net reinforcement has been introduced in the wall, it must be assumed that the design depends on the tensile strength of the concrete. This in itself will present challenges in relation to Danish norms. In addition, 3D Printers – State of the Art Page 16 of 34 over horizontal zones, where there is no tensile strength in the concrete, as the wall elements are not underlain. Here, the design must include the vertical coupling to the transfer of the feature, as well as the weight of the building. However, it is not immediately shown how the relationship between the wall elements is and how the forces run in the wall. It must therefore be expected to be difficult to get the design approved for Danish standards. However, WinSun has examples of the introduction of windscreens into the building by performing this windscreen in an insulated wall, see further in section 3.1.6, however, there are still no real ways in which disc forces can be absorbed into the building system.
3.1.5 Installations (electricity) Installations can be drawn immediately into the wall, but there are several examples of them being milled into the wall afterwards, see the pictures below. However, this should not be necessary if the design (installations) was better planned before printing. 3.1.6 Insulated wall element WinSun has made some considerations about designing an insulated wall element, but has not used it yet. In principle, a double wall is made where one part is executed with ribs / diagonals and the other without. The two parts of the wall are assembled at the ends, providing significant cold bridges. Winsun has not shown examples of how to insulate between the parts, a task that is considered to have performance challenges. One of the walls is not stiffened by diagonals, so there is room for insulation. The wall will, due to its 3D Printers – State of the Art Page 17 of 34 small thickness, will be challenged if it is exposed to vertical load as it is not stiffened by a diagonal.In practice, it will probably absorb some vertical load, even though all the load can be absorbed in the rear wall, and therefore will occur large cracks unless a connection is introduced between the wall and the back wall to retain the wall. For example, it could be with binders or reinforcement. It has not been stated whether WinSun uses any of the parts. In the form, WinSun suggested introducing a coupling that is inclined and can act as a crosswind. The connection is thus inside the insulation. The coupling interacts with the wall by casting concrete at the ends (ie top and bottom of the wall). However, this casting will in practice provide a cold bridge that will not be acceptable under Danish conditions. However, the above is an indication (however weak) of how slice forces are absorbed into the wall.
3.1.7 “Insulation” (waste) There was a somewhat different relationship to waste than in Denmark. It was very natural for WinSun that in the spaces between the diagonals, you put in all the construction waste you had, so you were free to dispose of it, see the image below. The waste was described as having a certain U-value, which is why it was considered as insulation. 3D Printers – State of the Art Page 18 of 34 3.1.8 Art / decoration / freedom of design One of the advantages of the 3D printing method is the flexibility of the casting / printing, as it is “free” to make variants / deviations. This was expressed, among other things, by the fact that several places had been made for plants to be inserted in the wall. This was done by failing to cast one side of the wall into an area and the notch could then be used as balcony boxes. 3D Printers – State of the Art Page 19 of 34 3.1.9 Finishing the walls WinSun had developed a method to automatically coat the walls. They claimed that the machine / printer was fully automatic in this regard as well. So there were two possible surfaces if one did not want the raw “printer look”. Wall polishing with automatic machine: Clothing with plaster:
It is also noted that in most of the houses there was a damp smell of “wet cellar”. However, this can probably be done with the installation of ventilation systems. 3.2 Tires WinSun uses two types of tires. 3.2.1 Traditional in-situ molded tires At WinSun’s “normal” 3D printed houses, WinSun makes the tires in the traditional way, ie as in-situ molded tires. However, they use the 3D printer to make formwork along the edge of the tire so that tire formwork is not necessary. This saves time especially when the tire is not right as there will be a lot of mold work in such a situation. The tire is lowered downwards like other in-situ molded tires via an underlying scaffolding system. 3D Printers – State of the Art Page 21 of 34 3D Printers – State of the Art Page 22 of 34 3.2.2 Wall structure “laid down” WinSun has, among other things for the office building in Dubai, performed the tire construction by casting a “ring”, which they have subsequently laid down. The ring has been reinforced between the concrete layers so that they have a high tensile / bending capacity. The rings are made at a height of approx. 1.5m and cast together afterwards (at the construction site). The casting will probably be difficult to get 100% close, so the solution will be challenged in the Danish climate. 3D Printers – State of the Art Page 23 of 34 Casting two “rings” / elements -> Molding threshold 3.2.3 Traditional Trapezoidal Plate Alternatively, WinSun performs their tire system in the same way as you know from the UK, where you make the underside of the formwork with trapezoidal panels (cast with concrete on top, composite effect) and these trapezoidal plates are then supported by steel beams and steel columns. 3.3 Pillars Columns are made immediately as formwork for an in-situ molded column, which means that after the installation (and before casting) the reinforcement is introduced into the column. By introducing diagonals, the column can presumably be designed in the same way as the walls for smaller loads without the introduction of column reinforcement. Note, however, that in such a situation there will be the same challenges with regard to molding for the columns as there are for the walls.
WinSun has 2 production halls that they want to produce from and want to expand production further, see section 1.2. During the visit, they further stated that in the near future they have plans to build a house over 100m, which they regard as a breakthrough in showing the possibilities with their building system.
It wasn’t easy, all I had was a town name and I had never been to Patchogue, NY before. I set off early in the morning not knowing what to expect, I had seen the address for the SQ4D headquarters online so I put that into my maps app and was on my way. Previously I had emailed SQ4D asking to come see their 3D printed house hoping they would provide an address but they never responded. I was on my way anyway but when I got to the headquarters there was no 3D printed construction to be found.
For the past couple years I’ve been following this industry intently even going to china to see the progress they are making with 3D printed construction technology. I do my best to cover the things I see on my YouTube channel so that other people can learn more about this emerging bleeding edge technology. I had already driven many hours and I was not prepared to give up just yet.
I did more research online and found an article in the Calverton, NY local news outlet about a 3D printed construction project that was 1,900 sqft the biggest currently in America. For the next hour or two I drove around the town of Calverton aimlessly looking for this unique residential unit but when I saw a large concrete plant I had a feeling that was a good place to look. It was a huge property but after making more than a few wrong turns eventually I stumbled upon the 3D printed house I was looking for! This made me one of the first outsiders to see this project! I hadn’t seen any detailed footage of the building so I took out my camera and recorded as much as I could.
Construction automation is an important field because it brings quality housing at an affordable price especially in markets where there is a construction labor shortage. Places like Guam, Puerto Rico, or California suffer natural disasters in the form of typhoons, hurricanes, and fires that leave tens of thousands if not hundreds of thousands of people homeless after disaster strikes. 3D printed homes can be a rapid solution that will last long term because concrete is strong. It can be hard for these regions to repair but over time as deteriorating residences are replaced by durable long lasting homes for distressed citizens the impact of the natural disasters will decrease and the community will be safer.
After I published the video I recorded, the company that build the house SQ4D actually saw it and reached out to me. They gave their approval of the video, which meant a lot to me because I was worried they could be mad I shared their work with the world. I look forward to covering all the progress that they make in the future.
Automated construction is not only beneficial for marginalized groups, Apis Cor has printed a 10,000 sqft office building in Dubai. Hopefully that is one of the locations I can visit next! If this upcoming industry is interesting to you follow me on my journey as I chase the future of construction automation.
The company was founded by a married couple, Anna and Nikita Cheniuntai. While Anna was studying Astrophysics in the Technical University of Irkutsk, she met a young self-made engineer with no university degree, Nikita.
Despite having no profound university level education, Nikita had years of experience within construction industry and machine building and a huge desire to start operating within the area of 3D printing. The first trial of 3D construction printing with the first version of the printer was done in Irkuts, however, not finished. The next project to be started was in Texas, USA, but also not finished due to the financial problems of the partner, who was primarily in charge of the project.
The first and only successful project was completed in Moscow Region, Stupino city, where on the concrete factory, there is a small house, claimed to be built within the 24 hours. Up-to-date, some of the main engineers in the company still lack university education. However, the official policy is that Apis Cor is interested in professionals with experience, who able not only to draw future and plan the developments, but who have hands-on-experience and are able to conduct a reality check if needed. Currently, Anna is playing a role of a Marketing Manager, Hr Manager and is in charge of communication with the partners, whereas Nikita is more concentrated on engineering type of work.
Originally, the company’s idea was to sell printers, however, with the help of investment advisors, they have decided to change their focus to providing printing services for big construction companies instead of having their printers sold out.
Year of establishment
Year of entering into construction 3D-Printing
Number of employees
Current number of employees of the company is currently growing and is estimated to be 15, including all the engineers, technicians and business support.
The company has its own printers, and provides printing services of houses at the customer request. Particularly, they are targeting large construction companies, that are ready to do market research and support the business operations on spot. Apis Cor, however, in its turn will be providing the technology, namely, the printer.
Development stage of printers
The company has 3 fully functional printers. It is a known fact that the newest built printer is currently in Dubai, whereas the other is located in the USA. The location and the stage of development of the third printer is yet to be known.
Development stage of printed materials
Apis Cor is currently using a modification of classical concrete mixtures, that are being slightly altered for the purpose of 3d printing. In Dubai, for instance, they contacted local producers that easily made the needed mixture.
However, currently, Apis Cor are exploring new materials, which includes geopolymer-based printing mixtures, such as Geobeton (Geoconcrete). They latter are trying to make the materials less expensive and it is claimed that as long as it is done, Apis Cor is planning to move its production to Geoconcrete due to its ecological and environmental characteristics.
The current status of all the patents that the company or its owner has is yet to be further investigated in details.
It is known that the patent is pending in the United States of America and there was always a plan to patent the product particularly in the States.
Largest print up to date (by size)
The size of the largest printed part or building up to date is 100 m3, a house in Stupino, Moscow Region.
The house has a location, approximately 112 km away from Moscow. It is located on a big concrete field factory, the main company of the town. The location was chosen primarily due to its smaller cost.
Normally, the house is covered with tent and has no heating on. The coverage was made due to the high interest of the house from the workers of the factory.
The showing is not done due to the marketing reasons. Apis Cor are afraid that by letting in a lot of media and companies some fake news and unwanted reports will be provided. Therefore, they are showing the house by request of the company, that has proven their interest in further partnership.
The interiors of the house was provided by several companies, that Apis Cor had found during their first house presentation. At that point, they promised to show a ready-made house, but instead, people came were only able to see the 1/3 of the house. However, this lead Apis Cor to finding partners to supply the furniture and other in-house equipment, like the oven, the fridge and the TV.
The windows were done by the company one of the engineers was working in previously, completely for free in exchange of advertising.
The ceiling was also done by company’s partners for free. The type of ceiling is tension (strength) ceiling, typical for Russian construction industry.
The provided TV fit perfectly to the wall, that has the same curve, particularly to fit the TV.
Due to the time limit, the interior was not done properly, and it is possible to see some scratches and cracks on the walls.
The house is widely claimed to be printed within 24 hours, which is not quite accurate. The house was built in 23 hours, however, all the time on solving the software problems and printer bags were excluded in calculation as well as all the interior works. In other words, in order to print just walls for the house it took the company more than two days granting the fact that it was their first project and some problems appeared were not anticipated.
The house received big media coverage worldwide, particularly in US. And attracted a lot of partners and agreements for Apis Cor. However, at the moment, they only construction projects they have are in Dubai and not in Europe. The project is the US is also frozen at this point.
Insulation system in the printed house was done using innovative materials of TechnoNICOL company. As a heat-insulation layer we applied solid plates on the basis of LOGICPIR hard polystyrene. Due to low thermal conductivity of the material (0.022 w/sq.m), thickness and total weight of the roofing system is much smaller than traditional insulation materials.
The movement system is similar to mobile robotic vehicle, however, instead of a robotic arm, a mobile crane is used for printing.
The maximum size of the printable area
Number of print heads (nozzles/orifices)
Print head (nozzle/orifice) features
Material feeding system
Included, fully-automated – There is an autonomous feeding system for the material, which is mounted on top of the printer, and is fully commanded by the printer.
Theoretical printing speed / Actual printing speed
0,1 – 0,2 mm
Idling speed X/ Y
20 000 mm / min
Price per printer unit
Multiple materials – The printer can use different types of materials one at a time, or simultaneously through the use of multiple nozzles.
Apis Cor is yet to release the details on the materials, but it is a known fact, that there are multiple types of materials to be used. Namely, traditional and alternative concrete.
Xtree is a young startup focused specifically on 3D Construction Printing. The technology is based on a material layered extrusion process, where a concrete-like material is pushed through a nozzle that moves around the printable surface and deposits a continuous line of material in several layers, until the whole height of the object has been printed. This process, also called Material Extrusion, is seen in most 3D Construction printing technologies, and it is essentially a large scale implementation of the Fused Deposition Modeling (FDM), a very common technology seen in personal desktop 3D Printers.
The XtreeE company is well-rounded, as it covers all aspects within 3D Construction printing, from software, through printer and material, all the way to consulting, either on their own or through their numerous partners.
The company is a young french startup dating back to July 2015, with its first steps dating back to Democrite, a university project focused on large-scale additive manufacturing. It has quickly attracted
strong industry partners in construction, cement, robotics and software, merging together all the important aspects necessary for a 3D printed construction project. Although still focused extensively on developing their technology, the company has managed to output an organically shaped pavilion, and the first 3d printed structure installed in a public building.
The company is guided by architect Philippe Morel, and a heterogeneous team of experts of various fields such as civil and mechanical engineering, computer science, management, material science, and architecture, the latter being the predominant field of most of its founders and current employees.
Apart from the 3D Printers, Xtree boasts a very technologically advanced design and consulting office, with all the most up-to-date technologies in use, such as Virtual Reality equipment, free-hand 3D design software, touch sensitive displays and drawing pads, and many more.
It has 10+ employees at the moment, with a strong will and plans to grow in the years to come. The company has mentioned the plan to move to larger facilities in 2017.
The company is targeting three separate sectors within 3D Construction printing, with its three separated categories of services:
XtreeE – Access – providing consulting services within 3D Construction printing, that helps the client measure and quantify the costs and benefits of employing such technology
XtreeE – Core – providing rental services of large-scale 3D printers
XtreeE – Platform – providing supervision of projects that use large-scale 3D printers
The young company has only a few projects and studies which have been released to the public. Although just a few, these projects are all very different, and represent each a small milestone within this developing industry. Some of the main ones include:
● The first structural 3D printed part installed in a public building – 4m-high post with a complex truss shape, which supports the playground roof of a school in Aix-en-Provence, France. The 3D printed part is actually the stay-in-place formwork of the structural concrete poured inside. However, it is still remains a very important milestone in the developing 3D Construction printing industry. It has been developed in partnership with LaFarge-Holcim, who provided the material expertise.
● The first 3D printed pavilion in Europe, with a strongly organic shape, made using generative design software. Commissioned by the Ile-de-France regional authority, it is a collaborative project bringing together XtreeE, Dassault Systèmes, ABB and LaFarge-Holcim.
● Pillars for YRYS, a concept house from Groupe Maisons France Confort (MFC), a showcase project for some of the most advanced and sustainable technologies in housing.
● First 3D Printed student accommodation, in partnership with organizations Habitat 76 and CROUS, a project still in design phase that will bring 3D printed housing to students of the University of Rouen’s Mont-Saint-Aignan. Planned for 2018.
● A 3D Printed drainage overflow shaft for SADE, for the municipality of La Madeleine in Lille, also the first of its kind.
XtreeE has currently two printers in their facilities, which still under constant development and optimization. They have recently added a new nozzle system. The printers are fully functional and have been extensively used for various projects and prototypes.
The material know-how is handled externally, by one of the strongest names in the concrete production industry, LaFarge-Holcim. They have selected and fine-tuned some of their products to meet the required specifications of the 3D Printing process.
The area on which the technology is capable of printing depends mostly on the robot used, which is approximately a radius of 4 meters. Most projects are printed in components and then connected on site. Some of the largest one include the 4 meter tall column, which was made of four components, or the 3D printed pavilion.
The XtreeE additive manufacturing process falls under the category of Layered Material Extrusion. This is a construction-scaled Fused Deposition Modeling (FDM) process, a very known desktop printer process, where a material in fluid form is extruded through a small nozzle as a continuous stream or filament. The material is then solidified on the printing surface, ready for the next layer to printed on top. While its desktop counterpart uses molten plastic, that melts when going through a hot nozzle and then solidifies by cooling down, the construction scale process is quite the opposite. Here a cement-based material, usually with properties and aggregates similar to a mortar, is mixed right before being fed into the machine. While still fluid, the material is extruded through a simple nozzle, which only helps to shape and channel the material, very similar to adding frosting to a cake. When the material reaches the printing surface it starts to solidify by itself in a chemical reaction with air, which is also known as hardening (first hours) or curing (long term, several days). This process has a considerable level of sensitivity, since material needs to be fresh enough to flow through the machine. When reaching the printable surface the hardening should not be completed entirely before the next layer has been printed, in order to ensure a good bond between the layers, but it should also be sufficient enough to sustain the weight of the following layer (or layers).
The printing procedure starts with the 3D model being sliced into layers according to the desired thickness, within the machine range. Xtree uses fine layers of around 3mm in thickness. Each layer is then translated into the instruction code for the movement of the nozzle around the printable area, using a programming language called G-code. Depending on the needs of the print, the machine can be instructed to:
● Print only the outlines of the object: This approach is the most typical and the most suitable one for formwork and walls, since it allows to print the outer walls of the object, and then fill in manually the space in between.
● Fill the object completely as a solid: this mostly done when a part needs to be heavy or structural (a solid is usually more resistant than a hollow material)
● Partially fill by creating a specific pattern/geometry: this type of filling is used mostly to reduce the quantity of material, the weight of the object, to reduce deformations that are induced from the material warping (less material, less warping usually), or similar reasons, while maintaining good strengths. It is usually done as a square mesh, but it can also be done in various specific shapes, if necessary.
Once the software has prepared a file with all the necessary machine instructions, the printing process can start. The concrete material is mixed in smaller batches, to prevent it from hardening too soon and blocking the machine (cement-based materials are usually workable for a few hours). The first batch is loaded into the pump, which pushes it to the nozzle and deposits it on a flat surface. Once the first layer has been printed, the next one can be printed on top. With each following layer there is some weight added to the structure, which will squeeze the first layers, making the whole print slightly shorter. XtreeE uses very fine layers, so this makes the problem less significant.
Once all the layers of the print have been completed, the process is finished and the object can be left to cure completely.
Since each layer needs to be printed on top of the previous one, the freedom of this additive manufacturing technology is more limited than others. The printer can create any shape in the horizontal plane, but once that shape has been chosen, it can essentially create vertical extrusions of this shape on top of it, or at least something contained within the shape itself, since it is impossible to start a next layer in midair. This type of printing freedom is not considered three dimensional, and it is often referred to as 2.5D freedom.
There is however a possibility to print each layer slightly leaning towards the outside compared to the previous one, slightly hanging over the edge. This allows to create mildly arched structures. While this approach is very common in desktop 3D Printing, where the sizes are very small and the materials are very light, it is much more complicated to achieve the same with a heavy and fluid material such as concrete, especially on a construction scale. It has a very unpredictable behaviour that depends a lot on the quantities that have been mixed, how long has the material been hardening, and many other external factors, such as wind. There is a high risk of the whole structure collapsing after many layers have been printed, losing a day’s work.
There is also a third approach, where a sacrificial support structure is printed and then removed after the hardening is complete, by using mechanical tools. The advantage is a higher degree of form freedom, but the cost of the extra work and material necessary can be a limiting factor in some cases, so each print has to be studied carefully to choose the best solution.
XtreeE has successfully printed in all three different approaches: vertically extruded objects, slightly overhanging structures with a gradual change in their geometry through their height, as well as supported objects with sacrificial material that was removed afterwards.
The printer requires a foundation for the robotic arm to be installed, and a flat surface to print on top of. The printing process has currently been used mostly in indoor and controlled environments, for prefabrication of components that were later installed on site.
There are currently two machines that XtreeE is using, both based on a robotic arm system with an attached nozzle.
The XtreeE printer uses a six-axis robotic arm from AAB, one of its partners. The machine is capable of moving in every direction with its reach, by a combination of movements of its six different rotational joints. The complex joint movements are coordinated through a specific programming software. The current models are used as fixed onto a foundation, and are best suitable for indoor use. The company has expressed an intent to make future models mobile versions, that can be used also outdoors.
Most of the details on the deposition system are proprietary and not released to the public. The deposition system is a single nozzle with a cylindrical shape. The nozzle is equipped with an electric motor that is used to fine control and push the material through it, probably through an auger coil inside the nozzle itself. The nozzle is attached to a rubber hose, that delivers the concrete through pressure. Between the attachment of the rubber hose, and the nozzle there is an additional controller with a small plastic tube attached to it. The latter is probably used to deliver some additives to the mix right before being extruded. The company has mentioned a use of additives that change the rheological properties of the material right before being extruded, and changes its viscosity. The delivery system is also shown occasionally equipped with air heaters, to facilitate the hardening of the extruded material.
The company has recently shown one of its printers equipped with a new nozzle. The latter is now encased in a plastic cover, so the interior components cannot be seen. No details on the improvements made to the nozzle have been disclosed.
The nozzle has been seen with various diameters. The most recent versions are shown with very small, 5-
10mm diameters, suitable for very thin layers of material (3 millimeters),, while older versions have been seen with much larger 30-50mm diameters capable of extruding larger quantities in less time. It seems that the company is focusing more and more on creating a precise print, as opposed to a fast print.
The material feeding components have not been disclosed to the public, although it is most probably an auger or piston pump feeding the nozzle through the rubber hose. These pumps are readily available on the market. The concrete is prepared separately with a standard mortar mixer, and then fed into the pump.
XtreeE uses very technologically advanced design software and hardware provided by Dassault Systemes called 3D Experience Platform. The printer hardware and software has not been disclosed, although it is said to be made and optimized internally by the company itself, and is still in development phase.
The speed of the system has not been disclosed, although XtreeE has mentioned printing a 2.5 meter wall in 5 hours. What can be seen from their nozzle in action is a speed of approximately 10-15 centimeters per second, which translates to approximately 0,02m3/hour. This means that the system can print a 2.5 x 2.5 m2 hollow wall with one face on each side in about 6-7 hours, which is not far from the stated. The XtreeE printer is on the lower end for speed, but the company seems more focused on the quality of the print.
The accuracy is hard to define at this point, as the printers are still in constant evolution. A trend towards the reduction of the nozzle and layer thickness size has been noticed, which indicates clearly that the company is focusing on creating a product that gives reliable and repetitive results. This can also be seen in the quality of their prints and the fine nature of the used material. The accuracy varies also depending on the shape of the print. A rough estimate would be around 5mm accuracy, which is on the higher end of the spectrum.
Theoretically, a single operator can operate the whole printing procedure, but the process seems best handled with at least two, one in charge of the printing procedure, and one mixing the concrete. In the XtreeE printing demonstrations there are numerous workers helping with the printing procedure, some checking or repairing the print during production.
Since the printer is essentially used in-house by XtreeE only, there is currently no official information on the time required to assemble or remove the printer on site.
Printer size (assembled): approx. 1.5m x 1.5m x 3.0m (Width x Length x Height) Author: Anes Jakupovic, 3DPrinthuset
Printer size (stored): Not available Print volume: radial reach of 4.2 meters
(Note: the robot can print 360 degrees around itself)
Printing speed (estimated): 0,02m3/hour Layer thickness: 3mm Accuracy (estimated): 5mm Deposition head: Single nozzle Structure: Robotic arm
Movement: 6-axis rotation Shape freedom: 2.5D Weight: Not available Energy consumption: Not available Required personnel: 1-2 persons Price per unit: Not available
The XtreeE has a great advantage compared to its competitors as far as material goes, since it has a partnership with one of the largest concrete producers in the world, LaFarge-Holcim. This allows the company to tap into a great knowledge resource, and finely optimize the material for 3D Printing purposes for years to come. XtreeE is currently using one of LaFarge-Holcim’s high-end products, called Ductal, a ultra-high performance concrete with some amazing properties. The mix ratios have been fine tuned by LaFarge-Holcim specifically for the use with the XtreeE printer.
Ultra-high performance concrete (or UHPC) is a novel type of concrete first developed in the 1980s for applications where very high strength and durability are required.
UHPC is produced with common concrete materials, such as cement, silica fume, sand, super-plasticizers and water. The Portland cement mixtures used are usually of very high strength, and there is also an addition of some unique materials like ground quartz and fibers, the latter usually made of steel. There are no large aggregates used, only fine grained sands.
The properties of this concrete are exceptional. It has strengths of 150MPa, and can go as high as 250MPa, beating traditional Portland-based concrete by up to 6-8 times. Same goes for flexural strengths and tensions strengths, reaching up to 40MPa and 10MPa respectively. Given the presence of steel fibers, it is very ductile, and can withstand repeated stress cycles and deformations. It is also self compacting, due to the high content of super-plasticizers and fines, which also gives it a very smooth and aesthetically pleasing surface with abrasion resistances comparable with natural rock. While being resistant to chemicals and damaging environmental factors, it is also resistant to cracking, shrinkage, thermal variations (freeze-thaw cycles), it is impermeable to water, and resists heavily chloride migration inside the concrete, that would consequentially corrode the steel inside.
UHPC is extensively used in prefabrication for various elements, due to its aesthetic properties, abilities to conform to complex and detailed shapes, and a good resistance to environmental factors. It is also heavily used in large civil infrastructures and seismic areas for bridge decks, beams, windmill towers, columns, and many more, due to its great ductility, durability and high strengths.
Ductal is a very well-known brand of UHPC made by LaFarge-Holcim, with a well documented history of more than 25 years. This exceptional concrete comes also with a very high price, around 20 times more than traditional concrete.
No specific details have been disclosed about the characteristics of the XtreeE printed material. Judging by the size of the nozzle and layers (3mm), it seems less plausible that the steel fibers are used when extruding the material, rather only when the mould is made out of clay, and the concrete is cast inside of it. This reduces greatly the many exceptional properties of ultra-high performance concrete, mostly ductility, flexural/tensile strengths, and cracking resistance. Though substantially reduced, the material probably still maintains some good compression strength, abrasion resistance, and low shrinkage.
Author: Anes Jakupovic, 3DPrinthuset
Since the printed material is made in layers, there is a reduced bonding between layers, which further decreases some of its properties. Namely, its tensile strength and impermeability are compromised, since a poor bonding can result in delamination between two layers.
The printed objects appear with a very fine layered surface, with a small amount of imperfections and errors in printing when compared to other technologies. The overall quality of the prints seems higher. The use of UHPC allows for superior mechanical properties, less shrinkage, and an overall more accurate, finely grained, and aesthetically pleasing appearance.
The finished prints are often ground or plastered to give them a more smooth surface.
Ultra-high performance concrete is a great material with an ever expanding research and use within the construction industry. When used as a 3D printed material, some of its properties are inevitably lost.
XtreeE has opted for a more fine layer and nozzle configuration, which deprives UHPC of its fiber reinforced advantages. Even if a larger nozzle would be used, which would allow for fibers to be extruded as well, they would probably end up oriented in a specific direction, following the trajectory of the nozzle. This would allow for increased tensile strength in the horizontal plane. But the main issue with the poor bonding between layers, a characteristic of additive manufacturing technologies, rather than a problem related to XtreeE, would still remain unresolved.
However, the use of UHPC mixes within 3D Construction printing are still justifiable and recommended in many ways. First of all, the process itself is a very expensive and time consuming process, especially when focused on high quality fine-layered printing that XtreeE is aiming for. This justifies using a more expensive material, that delivers better results for the same, limited amount of volume that is being printed. Furthermore, the low content of water in UHPC makes it less prone to shrinkage, which is a major issue in 3D printed parts, where a large surface of the material is exposed to air and evaporation. This can cause objects to warp, deform and crack, or layers to delaminate before even being put into use. Finally, the presence of fines gives the material a more even finish, and allows the printed objects to be easily smoothed or polished for an improved quality.
Overall, when comparing UHPC to traditional concrete within 3D Construction printing, UHPC is more expensive, but a better choice if quality is crucial, since it delivers a product with less issues and far better properties.
Minibuilders is essentially a layered material extrusion process, where a fused material is pushed through a nozzle and deposited in layer. This technology is very typical and well established both in 3D Printing in general (known as Fused Deposition Modeling or FDM), as well as in its construction-scale variants. But what sets Minibuilders miles away from all other process is a very innovative and completely different approach to actually printing the structure. While other technologies use gantries or robotic arms that move a nozzle around the printable surface, Minibuilders uses a swarm of small robots that work together, and even climb on top of the structure while printing it.
This project was aimed at developing the various specialized types of printer robots.
The Minibuilders project is under the supervision of the Institute for advanced architecture of Catalonia (IaaC). This educational and research center based in Barcelona sets its main focus on developing architecture to meet the worldwide challenges of the 21st century. It boasts a large digital production laboratory comprised of 3D printers, laser cutters, milling machines, robotic arms, chips manufacturing platforms, and many more. The institute has also various collaborations with other highly recognized institutions, such as the Media Lab of the Massachusetts Institute of Technology (MIT).
This has allowed for a wide array of highly technological ideas and projects to emerge in the last decade.
With a special focus on additive manufacturing and 3d printing on the large architectural scale, it is home to some promising projects on the 3D Construction Printing scene, which helped pave the road for many others. There is a strong collaboration with D-Shape and its founder Enrico Dini, who collaborated in various workshops and projects, and the institute has also designed the first 3D printed bridge printed with the D-Shape technology. Needless to say, Iaac is intended to stay an important player in this emerging field, and has already established itself as one of its early developers.
The Iaac 3d printing projects include Mataerial, FabClay, Pylos, Minibuilders, On Site Robotics, and TerraPerforma. They all share the same knowledge and experiences, tackling various aspects of a 3d printed construction, such as materials, movement of the printer, or the thermal efficiency of a printed geometry. They are essentially all part of a greater picture that is trying to bring 3d printing closer to architecture and construction.
The Minibuilders project is one of the many at Iaac, and it is mostly focused on the research of an innovative approach to 3D Construction Printing. The projects is developed by a team of researchers led by Sasa Jokic and Petr Novikov. The project has resulted in 3 different types of robots being developed, that work in a synchronized way, each with its own specialty within the whole process.
Since this is only a research project, there is no specifically target market for the moment, apart from construction and architecture in general.
The Minibuilders project has no direct predecessors within the other Iaac project, as its innovative printing approach stand mostly on its own. However, many positive outcomes and experience from other previous projects, such as FabClay, led by Sasa Jovic, have greatly contributed for this project as well. Mataerial, a project also led by Sasa Jovic, has used the same type of material.
The Minibuilders is mainly focused on the development of the printing technology. It has currently 3 working prototypes of small robotic printers, each with its own specialty. The project has also developed the main unit robot, that acts as a material feeder for the other smaller ones.
The project is not heavily focused on the development of the material, which has been known from previous projects. It uses a synthetic marble material, which cures fast enough to allow the robots to print fast and print overhanging structures. The largest known print up to date is a large oval wall that increases in size with its height, creating a slightly conical overhanging shape. The structure aims at displaying the potentials of the technology and is approximately 2 meters tall and 1.5m in diameter.
The Pylos additive manufacturing technology is a Layered Material Extrusion process. This is an construction-scaled Fused Deposition Modeling (FDM) process, a very known desktop printer process where a material in fluid form is extruded through a small nozzle as a continuous stream or filament. The material is then solidified on the printing surface, ready for the next layer to printed on top. Its desktop counterpart uses molten plastic, that melts when going through a hot nozzle and then solidifies by cooling down once deposited on the surface. The construction scale process is quite the opposite. Here a cement-
based material, usually a mortar or paste, is mixed right before being fed into the machine. While still fluid, the material is extruded through a simple nozzle, which only helps to shape and channel the material, very similar to adding frosting to a cake. When the material reaches the printing surface it starts to solidify by itself in a chemical reaction with air, which is also known as hardening (first hours) or curing (long term, several days). This process has a considerable level of sensitivity, since hardening should not be completed entirely before the next layer has been printed, in order to ensure a good bond between the layers, but it should also be sufficient enough to sustain the weight of the following layer (or layers).
What is also specific for this process is that the extrusion nozzle is mounted on several different robots that are smaller in size and move around or on top of the already printed parts of the structure. While other types of construction scale 3d printers are trying to increase their size to be able to print structures in architectural sizes, this approach has a great advantage of allowing the printer to be smaller than the object it is printing, avoiding the size limitations issue this way.
The printing procedure starts with a 3D model design file being translated into the path and the parameters of the specific robots printer during the printing process. This is done through a custom software, which generates a series of curves for each robot to travel along when creating the different parts of the object. These curves that are generated on top of each other are the actual layers of the object. The thickness of these layers depends on various factors, including speed of extrusion and the type of material used, since all materials behave differently under the weight of the layers printed on top. The Minibuilders robots create layers which are approximately 6mm thick, which can also be regulated through the moving speed of the printers. The software translates these curved paths into device control signals that are given to an external controller (a computer or similar device). The controller operates the movement and nozzle for each robot, and deposits the layers according to the curved paths. The printing of the whole structure is divided into three sections, each with a dedicated robot:
The first part of the printing is done by a Foundation robot, that lays the first 50 centimeters of printed structure, starting from a flat surface. The printer moves on flat surface and deposits the material through a nozzle located on the side of it. 1st phase – first 50 centimeters with Foundation robots
The second part of the printing is done by a Grip robot, that is fixed on top of these first 50 centimeters of hardened print. The robot grips on the previously printed layers and moves them while printing on top of them at the same time. With each new layer, the printer moves on top of the layers it has already printed, making the printed structure increase in height. The robot can print each layer slightly offset from the previous one, allowing to create gradual inclinations and overhanging structures or ceilings.
Finally, once the printed structure is finished, a Vacuum robot is attached on of the already printed surface and prints additional thickness layers on top of it. This allows to thicken the printed structure or create additional shapes on its surface.
All the three types of robots are attached to a larger master unit, which controls them and provides the
material. Once the last part or layer has been printed, the process is finished. The printed object is then left to harden completely.
The Minibuilders technology can print any shape in the horizontal plane and extrude them vertically, creating a wall. Each layer can also be printed slightly offset from the previous one, hanging over the edge. This allows to create walls with curved shapes by incrementally displacing each following layer. It is even claimed that these walls can be curved all the way to a horizontal plane, and that the printer can then directly print ceilings from that, thanks to the fast hardening properties of the material and the strong grip of the printer. The printer allows basically to print any three-dimensional geometry on any direction, provided that it is a continuation of the initial curve made through gradual changes of the same. The degree of freedom probably lies between 2.5D and 3D, thanks to the material properties and gripping approach.
This type of printing procedure and form freedom is most likely very sensitive to many other external factors, such as wind or heat, that might interfere with the hardening and compromise the bonding between layers, especially when considering the horizontally overhanging parts. Currently, the printer has created a slightly overhanging oval shape, while the printing of horizontal parts has yet to be seen.
The printer needs a flat surface, firm enough to print the first few layers with the Foundation robot, which moves around on continuous tracks (also known as crawlers). With layered material extrusion technologies there is also a possibility to print on curved surfaces, making all the layers follow the curvature. Although mentioned in one of their published articles, this approach was not yet seen in use in this project.
The printing process can be compromised with some considerable atmospheric agents, such as heavy wind or rain. Optimally, the printer should be in a covered environment. During the Minibuilders project the printer has only been used outdoors under good weather conditions, using a flat wooden surface as the printer bed.
The main focus of the Minibuilders project is the development of the various robot printers. The fundamental idea behind the project is to creae a swarm of different specialized robots that work
together, each on its specialized task in order to create the whole structure.
There are fundamentally four robots that have been developed up to now, one main supply unit, that provides the material and three printing robots. These printing robots essentially differ by the way they move around, each with its own degrees of freedom. They are described as follows.
The Main unit robot is essentially the brain that operates the Minibuilders 3D Printing technology. It is equipped with two material tanks, a two part polymer extruder, a controller (or PC) that coordinates the movements of the connected robot printers, and a set of wheels to allow the unit to move along with the smaller robots. There is also a couple of hoses and cables coming from the Main unit and connected to each robot printer in use, which is mounted on a high steel rod in order to keep them from interfering with the robot.
The first robot that start the printing procedure in the Minibuilders technology is always a foundation robot. This printer is essentially a small crawler with continuous rubber tracks , which is equipped with an extrusion nozzle that can move up and down along the side of a small vertical aluminum frame. This is the only robot that moves on a regular surface, behaving essentially the same as any other Material Extrusion printer. The nozzle extrudes the material while the printer follows the required pattern, by using a sensor that reads a traced line on the surface. This is repeated for each layer, until reaching the height of 15 centimeter, the maximum height the printer can reach. From here it necessary to pass to the next type of printer. The size of the robot is 26x35x37 centimeters, and it weighs 2.05 kilograms.
Once the first 15 centimeters are finished and the Foundation robot has reached its limit height, the printing has to be continued with a Grip Robot, the main printer of the technology. This type of robot does what it name says, gripping to the printed layers and printing on top of them. The robot is held in place by four wheels mounted laterally, two on each side . There is a spring in each of them, which tends to push them towards each other, and squeeze the previously printed layers into a firm grip. The whole structure of the printer is held together by an aluminum frame. The four wheels are placed on the bottom part of it, while in the middle there are two rollersthat help it sit on top of the printed
layers and move on them. The nozzleis mounted in the back, and features a lateral sliding mechanism, that allows it to offset each new layer from the previously printed ones. Behind the nozzle there are two hot air blowersthat help the layers harden quicker once extruded. The printer is 40x27x12 centimeters in size, and weighs 4.6 kilograms.
The most important feature of the Grip robot printer is the offset printing of each layer, that allows to create gradual curvatures along the height of the object. This is used when it is necessary to create inclined parts, overhanging structures, or various organic shapes. This is what gives the printer its three-dimensional freedom and allows it also to print ceilings, as a continuation of the walls.
Once the whole printer structure has been created, the third and last printer is used. The Vacuum robot is placed on the face of the finished surface of the printed object. The Vacuum printer is essentially a Foundation robot with continuous rubber tracks and nozzle, but with an additional vacuum generator, which allows it to attach itself through suction onto the vertical walls of the object and all of its overhanging parts and ceilings. By moving around the face of the structure, the robot can print additional layers, and thicken the structure where necessary. The robot’s structure is made of an aluminum frame and is 30x27x12 centimeters in size, and weighs 2.1 kilograms.
All robots use Dynamixel servomotors to power their movements, whether it is for continuous tracks, vacuum generation, nozzle movement, or rolling wheels.
The deposition system is made of two parts, which are located in separate positions. The first is the nozzle, which is located on each robot printer, and is essentially two plastic hoses that deliver the material and blend it into single one. The second part is the mechanical extruder that delivers the two components of material through the hoses to the nozzle, and is located on the Main unit robot. The extrusion is therefore controlled on the Main unit, and not on each robot separately. This simplifies the process, and allows the smaller robots to be free of additional weights of the bulky nozzle controllers. But on the same time this makes the control of the nozzle much less accurate. There will always be some residual pressure in the hoses that will create a time lag between the printing command and the actual starts or stops of the printing procedure.
The material is fed through two containers that are located on the Main unit robot. These are connected with two hoses to the nozzle, and fed through a two part polymer extruder. These are two drum containers, which are not continuously fed with material, but have to be refilled from time to time. This has been created for the purpose of the project, but for actual construction settings larger containers will be necessary.
The robots use Arduino on-board controllers to operate the printer. The software is written with the Arduino integrated development environment (IDE), and has been specifically adapted for the components used in project.
The printing speed of the Minibuilders technology may vary, depending on the robot that is used and how complex is the curve that needs to be printed. Generally speaking, the printers are very slow, capable of
extruding no more than 3-5 centimeters of a layer of material per second. That translates to a theoretical speed of 0,03-0,05m3/hour in best of the cases, which makes the realistic estimate even lower (probably as low as 0,01m3/hour), which is not suitable for construction use at the current state.
Similar to the speed, the accuracy of the printer is hard to define, since there are no official values given by the project, and since all robots move in a different way. Judging by what has been seen in operation, the Foundation robot is probably the most accurate, since it moves on firm ground. The Grip robot suffers the most, since every error in the printing can affect the correct positioning of the following layer, and there is a risk of accumulating errors and inaccuracies along the way. The whole technology should be within 30mm (Foundation robot) to 100mm (Grip robot) accuracy range.
There is no disclosed information regarding the printer operation. The printers seems suitable to be handled by a single person. It is important to note that both the Grip robot and the Vacuum robot require manual assistance when starting to print. They need to placed on top of the structure by a human each time.
Printer size (stored): Same as above Print volume: Not limited
Printing speed (estimated): Approx. 0.01-00.3m3/hour Layer thickness: approx 6mm Accuracy (estimated): 30-100mm (depending on robot) Deposition head: Single nozzle, double component extrusion (mechanical extrusion) Structure: Mobile robotic vehicle
Movement: Continuous tracks or wheels Shape freedom: 2.5D/3D Weight: 2.05kg (Foundation robot) / 4.6kg (Grip robot) / 2.1kg (Vacuum robot) Energy consumption: Not available Required personnel: 1 person Price per unit: Not for sale / Not specified
The Minibuilders is not heavily focused on the material it uses, but rather on the technology on how the material is delivered. However, the material still plays an important role in overhanging structures, thanks to its fast curing.
The project uses of a particular synthetic marble for their prints. The material is Axson Easymax, a two component polymer, mixed with marble powder. Marble is mixed in both components in a ratio of 60% of marble with 40% of polymer component. The blended components are stored in two separate containers on the main unit, where they can be stored for very long time. When extruded, they go through two separate hoses. They are blended together in the last part, right at the nozzle where the two hoses merge into a single one. Once the two components are mixed together, they start a fast curing process, which is completed in 2-3 minutes, and can also be sped up by using heaters. This fast curing allows the technology to print also in a horizontal or overhanging directions.
Synthetic marble is a composite material that is a mix of marble powder and various polymers, such as acrylic, epoxy, polyester, polyurethane etc. The materials are mixed together to form a paste, which is then cast into moulds and cured. It is has its own niche in construction, as it is used for kitchen and bathroom countertops that imitate the natural look of marble or granite. The benefits are a good abrasion resistance, shear strength, flexural strength, and impact resistance. It has also a more affordable price, as the variety of shapes and colors that can be achieved would be too expensive and labour intensive if made with natural stone. However, the price of the material is not competitive when compared with other highly available structural materials such as concrete.
The material is particularly praised for the fast curing properties and the usability time (until the two components are not mixed, the material can stay usable for months). However, the price of such material will probably be a limiting factor, especially in construction, where large quantities are necessary. In any case, it is the actual printing technology that shines through, while an alternative material can be easily picked from a variety of cementitious materials that are readily available on the market. There is proven, extensive and wide knowledge on cementitious materials such as shotcrete, which can also harden very quickly with good mechanical properties. These materials come in large quantities and at competitive prices, so they could be potentially adapted to this process, with some additional research.