Step 5: Material Extrusion

The material used by the robots must exhibit certain properties, strength, bonding strength, low cost and curing time. Curing time is particularly crucial to allow the robot to travel on top of layers previously printed whilst maintaining structural integrity. For the final structure we use a mix of 40% Axon Easymax two component polymer, together with 60% marble powder. Each layer is 6mm high and 16mm wide. The layers are bonded together becoming a uniform shell when cured. Shell curvature can reliably reach up to 90 degrees with a 30cm radius. It is also possible to increase the percentage of marble powder without loosing mechanical properties. However as the viscosity of the material increases the amount of pressure needed to move it through pipes also increases, which in turn makes control over material flow harder.

After mixing the marble powder with polymer component A and B, each are stored separately in sealed drums. These mixed material can be stored up to a month reliably provided the powder is without moisture when mixed.
When printing on site we utilised a professional two part polymer extruder. It was extruded a the ration 1:1 through high pressure pipes, attached to a custom mixing block which in turn connects the disposable static mixer nozzle. The nozzle is connected to the robot and curing in 2-3 mins, which can be accelerated chemically or by using heat.

The extruder is also mobile, considered “the fourth robot” it supplies material, power, controllers, heater control panel and extruder flow control panel. The fourth robot follows the small robots while printing demonstrating two levels of mobility within the system.

The images included in this document may show differences due to the prototyping that was constantly evolving the system.

We have tried to make the robots as open as possible by sharing the specifications within this scientific paper.


The project has also featured in a number of publications, see below for further information.





Research Team: Stuart Maggs, Dori Sadan, Cristina Nan, Jin Shihui

Faculty: Sasa Jokic, Petr Novikov

Project by: Institute of advanced architecture of Catalonia

Sponsored by: SD Ventures

<p><em>&quot;Small Robots&quot;?!?</em></p><p>They really are tiny (compared to earth) :)</p>
<p>What is the material that you are using?</p>
<p>Brilliant work! I was hoping it was a more general print bot than the three separate specialized bots, but specialized bots could also be added to accomplish other tasks of construction such as plumbing and conduits for electrical systems. A small &quot;pipebot&quot; could make structural tubing around itself, possibly with a second print head for a rigid foam core. Coordinated little pipebots could make honeycomb cell structures for strength. A fiber placer could also be rigged to insert fibers that stick through and up out of the bead allowing higher strength before the need of the vacuum bot.</p><p>Man does this have my gears turning.</p><p>Thanks!</p>
<p>Brilliant rethinking of 3d printing for large structures!</p><p>The flexibility of these robot's capabilities seem like they would be very impressive, but I find myself wondering if a much cheaper and simpler version could be designed to create simplified housing for disaster areas and other low income communities. I imagine something with a shape like a beehive sort of like the domes created by spirally winding continuous sandbags like these:</p><p><a href="http://www.earthbagbuilding.com/projects/smalldomes.htm" rel="nofollow">http://www.earthbagbuilding.com/projects/smalldome...</a></p><p>The device would not even need much in the way of computing power. The extruder could be guided mechanically, Sort of like this:</p><p><a href="http://jimsoven.blogspot.com/p/the-dome-part-i.html" rel="nofollow">http://jimsoven.blogspot.com/p/the-dome-part-i.htm...</a></p><p></p><p>Of course for this purpose using local materials would be best, but if the polymer/marble dust is cheap enough it would still be practical.</p>
<p>Is this thing DIY? Are there plans available?</p><p>Maybe there is a link here, but I don't see it.</p>
<p>I would like to suggest that, rather than using suction to hold the third (suction) robot in place, you take advantage of the inherent complexity of the structures that the grip robot can lay down, and have it &quot;build in&quot; a track for the suction robot to hold onto and follow. For instance, the grip robot could make a small series of indentations beginning every 0.2 meters horizontally and continuing throughout that horizontal layer. Then it would create an overhang in subsequent horizontal layers. The third (suction) robot would have notched wheels that would fit into this track, holding it to the surface. This would eliminate the need for a complex, failure-prone suction system, and also provide a built-in self-metering (measuring) system that would improve position accuracy. If I'm not being clear please contact me and I'll make a diagram. </p>
<p>that must be quite expensive!! how long did that take?</p>
My brain just melted. Really quite awesome.
This is by far the most incredible and amazing thing ever to come out of instructables. This is so inspiring.
<p>How much for a boat? great ible!</p>
<p>This is really cool. Basically a six-axis 3D printer. I want one.</p>
absolutely awesome! 3D printed house anyone!??
<p>Oh yeah.</p><p>Waste-free construction is the future!</p>
<p>Amazing work. Thank you.<br>And now for something that will make you laugh.</p><p>Your incredible project reminded me of part of a 1974 movie (not very good, except in parts) called The Groove Tube. <br>The part you have to see is this <br><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/008BPUdQ1XA" width="500"></iframe></p>
<p>I take it the building material doesn't shrink much, or cracks might form. Rebar, or mesh, or some sort of fiber worked into the material is the usual solution in cement construction. This appears to have none. Do you ever wish it had some back-up fiber worked into the form?</p><p>A really nice instructable. Thanks. </p>
<p>Awesome, but please edit the audio so the &quot;music&quot; is 1/2 the volume. The people speaking have accents (to English speakers) and the obnoxious volume smothers their voices. And those of us who find this amazing would prefer to hear them, not the electronic buzz behind them. </p><p>loved it, I often thought what a hoot it would be to connect a pump/feeder to a fast set plaster/cement kinda like spray on cement. As I have no ability to make that I love that someone else did. </p><p>Bravissimo</p>
<p>I love your 1st paragraph :</p><p>There has always been a close relationship between architecture and technology. However, recently architecture has stagnated and the construction industry has been slow to adopt technologies that are already well established in other fields. Whilst we design digitally we still construct manually.</p><p>Thanks for sharing</p>
That is extremely cool. Except for one picture in which the device is being pushed by someone, it is very hard to understand the size of the objects. A human operator perhaps for proportion in the images?<br>A time lapse video of this project will win the interwebz :)
<p>Just saw the video which was not visible in the instructable app. The process is well thought of and the robots work well. I especially liked the third one which sticks with suction.</p>
<p>Wow, amazing!</p>
<p>I remember seeing this project elsewhere online a while ago. Thanks for posting to Instructables! I love this idea.</p>
<p>Wow, wow, wow... Absolutely amazing. 3d printers are the new future of buildings ,architectures, engineering, industrial, design and art.</p><p>Try contact with NASA, they are working with private corporations on giant 3d printers to settle bases and buildings on planets.</p>
Impressive! And everybody keeps complaining about the ever too small max sizes that 3D printers can spill out. :)
<p>This is so innovative and cool! I'd never thought that tiny 3d printers could be so capable at printing anything bigger than them... Nice job, thanks for sharing!</p>
this is really cool. it's amazing to see everything these 3d printers can do

About This Instructable




More by Minibuilders:Minibuilders - How to 3d print big structures with small robots 
Add instructable to: