Aug. 26, 2014 | By Alec

In Minnesota, contractor Andrey Rudenko is currently working on a project of gargantuan proportions that seems to be stretching and exploring the limits of 3D printing technology. Using a printer that was substantially modified and expanded, he has printed a concrete castle in his own backyard. And at 3 by 5 meters, this concrete structure is the world's first 3D printed concrete castle, and one of the largest objects that has, up till now, ever printed with 3D printing technology.


Rather than trying to build a machine that caters to theme parks and history enthusiasts, this project grew out of a desire to construct a 3D printer capable of constructing durable, realistic and inhabitable houses. He's already looking at various locations to realize this: 'last winter in Minnesota, which was long and frigid, showed that it is crucial to have multiple areas in different countries for experimental printing since you can never predict which conditions will arise.'

But Rudenko, who has a background in engineering and architecture, chose to firstly print his fantastical castle. This allows its creator to search for and experiment with the limits and possibilities this machine offers to construction companies. The castle's unique features and shapes offers many challenging opportunities to do this, and leave room for Rudenko to make minor adjustments to the machine. And of course, it's also a wonderful showpiece for his huge 3D printer.


As Rudenko told 3ders.org, this project follows years of preparation and planning:

'I've been interested in this technology since I was in my teens. My concrete printing experiments started about 20 years ago, but at that point, advanced computers and software were not available for this type of technology. It wasn't until a couple years ago that I came across the RepRap project and started working on this machine again. It took about a year to build and develop special concrete mixes. Additional inspiration came from the naturally-laid layered sandstone I saw on a trip to Arizona a few years back. Ideally, I hope I can obtain the same natural look to my printed walls.'

Furthermore, progress was also hampered because of the finances involved. Rudenko therefore ended up financing the printer independently, which led to many creative engineering solutions.

'When I was starting out, potential sponsors were wary of providing funds since they did not think the technology would go this far. Once the castle structure is built and the capabilities of the printer are evident, I plan to conduct an auction of the ownership to the first house; since this will be the first functional 3D printed house ever built, I'm hoping there will be a lot of takers and this will become a valuable landmark.'


A project of this size obviously needs a printer of corresponding proportions, and Rudenko necessarily built his own machine. While he has received lots of very helpful feedback from the RepRap community, the actual construction was of his own design. This massive machine is driven by Arduino Mega 2560 board and software, which is not too different from some other 3D printers, but it requires special stepper drivers 'For a big printer, I need special drivers that can handle the heavy weight of the machine as well as be compatible with the software/firmware. The best fit I found was from James Newton's Mass Mind.'

'These drivers ended up being the only ones to work properly with Marlin Firmware (I sampled other drivers, which failed), and were powerful enough to move such a huge printer.' Rudenko added.

This printer is therefore slightly different than the one developed by Behrokh Khoshnevis at USC. 'Design-wise, I'm creating a natural, free-layering of fine concrete and my goal is to have a nice-looking, natural texture, without the need for any additional finish, similar to rammed earth technology.' Rudenko is also seeking to develop a portable machine that even smaller construction companies can afford. 'The final price will be known once we build a few houses, but to the best of my knowledge, I currently see it as being priced at $30,000-50,000, though this will also vary depending on the parts and type of model.'

When that time comes, Rudenko hopes to be able to deliver a number of different kits that individual customers and small companies can put together themselves. 'Obviously I can't ship the whole machine, but I can ship an extruder, control box, some major parts, etc to help individuals put together their own version.' Khoshnevis's printer, on the other hand, at least appears to be heavier and larger, and Rudenko expects that only large-scale construction companies will be able to afford it.


The building process of this 3D printed concrete castle is now complete, but it's also a learning process for Rudenko's future plans. He's currently printing approximately a layering of 50 centimeters per day, though the size and width of the layers vary throughout the construction. Regular layering is being printed at 30mm width by 10mm height, but Rudenko can print layers of virtually any size. 'For special areas like crown moldings, I am reducing the height to 5 mm; I'm also reducing speed in delicate arias.'

Of course, a construction of this size requires the right materials to sustain the sheer size and weight of the concrete.

Rudenko said, 'Layering cement was an extremely difficult task- it required extensive tuning of the printer on a programming level, as well as using exact quantities for the cement mix. While testing the printer, I ran into obstacles (such as the nightmare of the extruder clogging) and discovered even further abilities of the printer, like that it can print much more than 50cm a day as I originally thought.'

Rudenko therefore resorted to including rebars in the bottom and top walls. 'They are needed during the pouring of a variety of cementitious filling materials inside the printed walls.' The cement used, however, is just a regular cement mix with a few additives. 'It is possible to use a special quick-setting concrete to speed up the process, but it will affect the cost, and I don't see much reason to build a house extremely fast at the expense of higher cost and lower quality.'

Instead, Rudenko is after quality and new possibilities. 'The more important advances of this technology lie in its architectural possibilities and energy-efficiency. Architects have waited many years for this technology, and now that it's here, this opens up a whole window of possibilities; soon, we will see new kinds of architecture used to construct new structures.'

This Minnesotan constructor is seeking to a part of this: 'I plan to concentrate on the development of further 3D printing technology in construction and building a community/network of people worldwide interested in research and development of this technology, with the possibility of providing DYI kits as well as a full line of model construction printers.'

For now, however, printers that are suitable to construct homes and be commercially viable as well are still in the distant future. But Rudenko is optimistic about the possibilities for both his device as well as this industry. 'My current standard is 10 millimeters in height by 30 millimeters in width, but countless other options are available with just the click of a button.' he said.

Rudenko is in the process of redesigning the printer based on the lessons learned. His goal will be to have an upgraded printer that prints 24 hours a day until the project is finished.

'I'm also planning to print the structure in one piece; printing the castle turrets by themselves was a bad idea as they were extremely difficult to lift and place. Additionally, I've figured out how to print a roof; the only thing is that the material I'd print with would have to be used in warmer climates for now.'

Rudenko's next project is a real full-scale livable house. 'The amount of correspondence I am getting proves high demand and interest in this new technology. I want to make sure that for the next project, I have the right team doing the job to fully use all of the benefits of the 3D printing machine.'

'I am open to offers from individuals or companies interested in owning the first house of this type built with the newest 3D printing technology and ready to provide abundant funds to completely cover the project and all its expenses. The interested party needs to own the lot/site and possess a permit for a house built by 3D Printing technology.' Rudenko would also like to collaborate with the interested architects, designers, and software engineers experienced in 3D tools. And you can contact him via this email for further questions.

It has been two years since Rudenko first began toying with the idea of a 3D printer that was capable of constructing homes. 'I have previously been sure I could print homes, but having finished the castle, I now have proof that the technology is ready.' Rudenko said.

'The current prototype I am working on at the moment is just a small part of the line of printers I am designing. We are talking about the beginning of a new era in construction industry. There is still much to be done.'

Watch a video of Andrey Rudenko's printing process here:


 

Posted in 3D Printing Applications

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Dana wrote at 9/4/2014 5:13:57 AM:

Why in the world would I want to print a house? That is unnecessarily complicating something that ought to be fairly basic. On top of that we already have a problem with not getting enough activity in our daily lives, so let's just invent more machines that leave us doing nothing but pushing buttons. Nah, pass. I'd rather put my energy behind the natural building movement, techniques like straw bale and rammed earth and cob--and if your next objection will be "what about disabled people" I would counter that with "what about helping your neighbors out when they need it instead of leaving them having to resort to expensive machinery." I dunno. With all that I do think the idea of 3d printing is nifty, you just can't replace EVERYTHING with it.

Steve & Kam wrote at 9/3/2014 2:31:45 AM:

I just watched this with my 8yo son and we LOVE IT! Great Job!!

Kinreay wrote at 9/2/2014 10:41:39 PM:

How do yo (or do you?) install re-bar? Concrete is strong in compression but there will be other forces acting here that need to be considered. Mention was made about re-bar on the corners but I'm thinking you'd need much more. Looks like a great idea with huge potential. Thanks.

Andrea Abernathey wrote at 9/2/2014 6:12:06 PM:

Love this! Tried to get your email off here but it said webpage wasn't available. Would like to see castle in person please. I am also very interested in the future of this. My family has property in La Porte Minnesota. Please contact me. aa2gd2btru@yahoo.com

Anonymous Coward wrote at 9/2/2014 1:34:16 PM:

I can't see this fly until the problem of printing on an already in-place rebar structure is solved. Without rebar, concrete buildings are extremely sensitive to earthquakes. But the idea is great. Maybe printing with a mix of synthetic/glass fibers and concrete, instead of just pure concrete, would yield a material of enough tensile strength to make rebar unnecessary, while labor savings and building speed increase still keeping it reasonably priced, overall.

Monk wrote at 9/2/2014 2:06:39 AM:

A few more upgrades and modifications and future archeologists will be totalaly baffeled. Again.

Aaron wrote at 8/31/2014 9:57:01 PM:

Replace (tool change?) the print head with a solid cylinder and then make another pass, offsetting the cylinder such that it rides along the outer surface -- no additional DoF needed.

builry wrote at 8/31/2014 8:52:11 PM:

robo paint scraper adapter connected to the extruder

Oilman2 wrote at 8/31/2014 3:59:05 PM:

OR, you could simply spend a few days applying stucco or mortar by hand to make it look the way you want - personalize it. EVERY homeowner wants to differentiate their tract-design home to express individualism. Most people will never design a house - just pick from existing designs. But most homeowners apply their own touches on weekends, and filling the recesses between layers is simple and can allow widely different 'looks'.

Jae Kwon wrote at 8/31/2014 11:27:52 AM:

This is fantastic. A rotating print nozzle with the right shape nozzle could help with the look. The nozzle hole would be rectangular and it would lean a bit to the side.

david wrote at 8/31/2014 7:06:17 AM:

There's another option for a smooth finish, or a finish with a different texture: stucco. The printer could easily create nubs, or short spines, at regular intervals that would act as supports for another coating. That coating could be sprayed concrete, or it could be stucco applied traditionally with a trowel. Masons can create a wide variety of surface textures quickly with a trowel. So the proposal here is to let the printer do the structural part, and details like cornices and dentillations, but leave the finish of broad surfaces to professionals with skills.

tom wrote at 8/31/2014 6:24:33 AM:

Have they discussed how they would wire it and also - any discussion for additional insulation in the wall cavity? Love this - awesome work so far.

alidan wrote at 8/28/2014 11:52:03 AM:

@Julio you could probably do something to get a paint scraper to do the work, but it would need to be an engineered process really what you could do is have an outside edge pre determined, and have something that would hold an outer layer of concrete on it to smooth that crap out. personally, i love the layerd look because i could fairly easily get some ivy to grow up it and make the whole thing covered in green.

Julio wrote at 8/27/2014 9:52:49 PM:

Adam, that's not possible. You would need to orient the scraper along the outer surface and in this design the extruder doesn't rotate. You would need an extra DoF. So not "hell, duct-tape the paint scraper to the print head". Think a little more.

Adam wrote at 8/27/2014 4:15:32 AM:

I think 3d printing concrete gets a bad rap because of the unfinished look of it, the ridges and all, but really you could just go over it with a $2 paint scraper and smooth out the outer walls and it would look completely legit and professional. hell, duct-tape the paint scraper to the printhead ( a few inches down) and the smoothing process is now automated. can't wait to print a castle of my own. one day you'll either have your own concrete printer, or rent it from the hardware store for a weekend like any other large tool.



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