Benchtop Rapid Prototyping for the rest of us?

Rapid prototyping is an offshoot of CAD/CAM that promises many benefits for the amateur roboticist, and even for the professionals! Think of it as 3d printing- you start with a computer model of the shape you want to build, feed the data to the prototyper, and a solid (or hollow) 3d object is built for you. Sounds cool, right? Unfortunately, the cost of these machines has been prohibitively high for the average citizen, even with the promise of the yet-to-be released Desktop Factory at $5000.

But what if you could build your own prototyper, using components designed specifically so the prototyper can create them itself: you now have the potential for a self-replicating machine! The folks at have exactly that aim- to design and build a self-REPlicating RApid Prototyper:

A universal constructor is a machine that can replicate itself and - in addition - make other industrial products. Such a machine would have a number of interesting characteristics, such as being subject to Darwinian evolution, increasing in number exponentially, and being extremely low-cost.

A rapid prototyper is a machine that can manufacture objects directly (usually, though not necessarily, in plastic) under the control of a computer.

The RepRap project is working towards creating a universal constructor by using rapid prototyping, and then giving the results away free under the GNU General Public Licence to allow other investigators to work on the same idea. We are trying to prove the hypothesis: Rapid prototyping and direct writing technologies are sufficiently versatile to allow them to be used to make a von Neumann Universal Constructor.

The Darwin (RepRap v1.0) design consists of several open-source modules: A cartesian robot to move the print head in XYZ space*; a thermoplastic print head that melts a solid strand of building material and extrudes it in a fine, molten thread to build each layer of the object; host software that converts a 3d model in Stereolithography file format (.stl) into motion commands; and PIC-based stepper motor controllers that convert motion commands into stepper motor sequences to move the robot. Each module is itself decomposed into subsystems, allowing the builder to work at their own pace and to debug each section as it is completed. (*actually, the print head moves in the XY plane, while the build platform moves down the Z axis as each layer is completed)

Here is an example of some RepRap parts that have been produced by Vik Olliver; more parts can be seen at the RepRap gallery.

Vik's RepRap Parts

Although one goal of the RepRap team is to bring the costs down to ~ $600 (400 euros), currently it may require an outlay of more than $1000 to acquire all of the parts and pieces. Still, this is coming within dedicated hobbyist range, and as more RepRaps are built, the cost of parts should drop radically. Every builder is encouraged to use their Darwin to produce the parts for one or two more Darwins; ideally, this would lead to an exponential increase in machines.

Of course, there is a chicken-and-egg problem here: somehow, you have to build a RepRap in order to build the parts for another RepRap. This leads to the RepStrap concept: a bootstrap machine that can produce RepRap parts, though not itself built from those parts. This is what I am thinking to build, starting with some second-hand cartesian robot parts that I've acquired, and adding the RepRap printhead and control software. Let me know if you're interested in hearing more about this project!

A similar project, though not self-replicating, is showcased by the Fab@Home project. This project also offers plans, parts and software to allow individuals to build their own 3d fabber; in this case, using a syringe-dispensed building medium rather than molten plastic. However, it is quite possible to build toolheads for a variety of materials, including conductive pastes, plastics, wax, etc.

Materials cost for a Model 1 fabber is projected at some $2300 ( ~1600 euro), and partial and complete kits are also available for $3000+. The Fab@Home projects are built with ARM7 microcontrollers with built in USB 2 support, which is handy considering that most home PCs no longer have standard RS232 serial ports!


Peter Redmer's picture

This is really cool, and complicated stuff.  If you build one of these of your own, we just have to see it :)

I can only imagine what even the amateur roboticist would come up with, with the power of this tool.  the possibilities are endless, right?

Great stuff! 

RobosapienV2-4mem8's picture

Oh hell, I want one, Just think how easily Wall-E could have been built, M'mmmm any more details milw?? Where parts can be procured.

Ok, found what I needed to know. 

General Fabb's picture

If you’re interested in following the news on 3D Printing and digital fabrication, you might consider our blog at :

GWJax's picture

I have to build one this would make mold making a thing of the past. I'll start saving for this or find a way to make it out of copier and printer parts.

spikegomez's picture

This is really really cool man, so with this thing we could do any or more thing??? Rapid Prototyping

RobosapienV2-4mem8's picture

well GW, Looks like another project to add to our lists, Yes If you build one I will have to also he he.

spikegomez's picture

So that is really great then.

GWJax's picture

4mem8 this was the Fab machine that I was talking to you alot in our AIM texting. This will be an increatable project because if we have a product that we cadded and printed then we could just send the data file via the net and you could print the same thing that I print. I guess this is the next best thing to a telaporter unit. hehe I'll let you know when the project is underway.


spikegomez's picture

That is a very expensive prototyping machine but it looks really useful for prototyping effectively.

GWJax's picture

Finally I have one but not the RepRap Printer, I have the MakerBot Cupcake Ultimate.

Built it about a month ago and I'm still learning how to use the 3D CAD programs to build robotic parts with. :) The only down side of my 3D printer is that the print area is only 100mm x 100mm x 130mm, So big parts can not print on it unless you break it down and put it back together. I'm printing out a larger printer called the CUBE that can be found on and on this site you can find a ton of things to print with your 3d Printer. Sending data files of your CAD parts is as easy as just sending an attachment in your e-mail. Talking about transporting your parts around the world, I love this printer..


Rose Wilson's picture

I work for a charity called Techfortrade.
Currently I am working on how 3D printing can be used for social benefit in the developing world.
We are launching a competition, with a prize of $100,000 for somebody who can come up with a brief proposal on how they can use 3D technology for social benefit, proving that they just need a bit of extra funding and technical support for the idea to come to life.
More details can be found on our website:, twitter and our Facebook page: Techfortrade.
Alternatively email me at: