Let's Make Robots!

Doboz: Repstrap 3d printer made of Aluminium and plexiglass

3d printing, a bit of 3d scanning


Hello everyone ! Since this machine has just finished producing its first "offspring", i thought i would submit it here to commemorate.

This is my first generation "Repstrap" machine , on which i worked for many months.

  •  A repstrap is a derivative of a Reprap (open source 3d printer) , that is not created using 3d printed parts (sort of like "bootstraping" such a machine) 
  • as with most machines of this kind, it prints 3d object using thermoplastic filament that gets melted and extruded via the print head, depositing layer after layer  
  •  The structure is made of L-Shaped aluminum : outer volume is 39*35*45 cm Early build of the structure
  •  Total build volume ( maximum size of objects that can be printed inside of it) is 21*18*23 cms - I used a threaded rod approach for all axis of the cartesian bot (in hindsight, not the best idea, as low quality threaded rods make movement way too slow) 
  • Custom, low cost home made electronics to control all stepper motors , the print head heating , and the heated build platform (used to avoid warping in cooling objects) Doboz-electronics
  • it also has a very limited 3d scanning ability, using a simple IR-Led/Photodiode combo , to generate 3d "height maps" of the objects in the machine .
  • overall, a rather slow but rather reliable machine ( many 24/7 prints) It has already allowed me to experiment with different mechanical components, and has just finished printing its first offspring; a mini reprap!


A 3d printed mini turbine

Baby is born!

The build process was spread out over about 8 months, with many prototypes, and experimentation, i had never worked on something this complex before, and even with the occasional tantrum etc, great experience :)

You can view more info and aspects of the build process on my site :http://www.kaosat.net/?tag=repstrap





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I can tell it was a labor of love, difficult as that can be sometimes.  At this point how many successful parts has your Repstrap made?  Is it busy now?

Thanks a lot Grog! Yes, you are quite right, however long the process , it was still definetly worth it : It is fascinating to just create/download a 3d design, and then have it appear before your eyes as a real object!

Also now that it has matured, i will be able to print elements for mobile robots (amongst others): i have been drooling over the amazing machines on display here for quite a while now:) 

As for the total number of parts printed so far :

  • at a quick glance, around 100-150 parts that are completely ok (acceptable quality, mechanically functional)
  • perhaps around 40 incomplete/botched prints (things that went wrong , diverse failures, unaceptable quality)
  • the quality and reliability got steadily improved, so there were only 2-3 failures out of the last 50+ batch of printed parts :)

Unfortunalty i had a major electrical problem last week, and its motherboard "died" ( i have no idea what is wrong, all electrical checks are ok, all indivudal components still work, but no reaction), so waiting for replacement parts to repair it, otherwise, it would be printing, as almost always :)

Sorry for the late reply guys!



  • i took a look at your CNC machines, and they look fantastic !  mightly impressive work ! i might have missed it, but , big big question: did you manage to make some pcb milling ?.
  • Yeah, the extruder is the hardest to manufacture using diy methods and tools, but it is still feasable, using lots of experimentation, based on what elements you can find locally (or not, in the end i managed to find some relatively cheap print heads online, but i had working , full diy versions before that, but given my lack of precision metal working tools, the quality was not top notch)
  • Extruding 3mm Nylon must be feasable as well , although i would be a bit wary of fumes, and you would need to find the adapted melt and cooling temperatures, most likely.
  • the general movement speed is not  limited by the extrusion feedrate at all : in fact , i had to go to almost the lowest possible speeds for the stepper that is driving the filament , as the machine is so damned slow , but after a few adjustements it works just fine
  • your are right about noise and dust :) , i originally built my repstrap to be used both for plastic extrusion and milling /cnc , but given that i live in a tiny flat, i put the idea of CNC aside for a while ( i actually leave the printer running at night sometimes and i can sleep , would not be possible with a Cnc :))


  •  tinhead got that right, i use the reprap software , or rather to be more precise, i use a modified version of the reprap 5d firmware (one of the many, many firmwares for repraps, that can be uploaded to the atmega/arduino/sanguinos controlling the machines, and the commands are indeed text based GCODES sent via usbSerial . The host (pc side software, is homebrew, a bit unusual : as it is a server /client solution for remote monitoring and control  ( still in early development): http://www.kaosat.net/?p=1731
  • the main problems:  speed (the new "child" machine will be somethings like 40 times faster, huzzah!) , slightly flawed electronics design (my fault, went really "guetto diy") , the endless fine tuning