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.'



http://www.3ders.org/images2014/world-first-3d-printed-concrete-castle-13.jpg

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.'