I got an awesome question came in from the fine folk of the San Francisco making society that actually stumped me a bit.

Do u know why RepRap picked FDM and not another 3D printing technique? Patent issues?

A digagram showing the FDM printing process taken from the original patent application

I was stumped because RepRap is not really a single person or company that I could ask or call. It is a distributed (and often chaotic) group of people loosely congregating around a bunch of ideals. Not everyone shares the same vision, or even agrees about core ideals. But the concept of printing stuff in 3D in your own home is what brings us together to invent, collaborate and sometimes argue.

So what ideals led to FDM or Fused Deposition Modelling being primarily associated with RepRap and not one of the many other 3D printing techniques?

Adrian Bowyer started the RepRap community by offering the first couple of ideals:

  • A machine that is self replicating, where A 3D printer that can print out a significant fraction of it’s own parts (although not all of them).
  • The parts that it can’t print for itself are all designed so that they are universally available anywhere in the world for very low cost.
  • Open source, so you can download the design off the internet for free, print them yourself and give it to a friend.

3D Printers based around Fused Deposition Modelling, just happen to the easiest to build and maintain that also satisfies these ideals. Which I think is the mostly likely reason why more and more people have been building, extending and improving upon the original Darwin design.

So why not another 3D printing technique? Well actually, the RepRap community isn’t just experimenting with Fused Deposition Modelling. People are working on selective laser sintering designs as well as stereolithography. They are not as mature or as popular, because the parts are harder to obtain and they are considerably more difficult to build.

Patent and Trademark Issues

So what about Patent Issues? Well enter the 800 pound 3D printing Gorilla, Stratasys. They actually trademarked and own the term ‘Fused Deposition Modelling’ So technically, most RepRap printers are FFF or Fused Filament Fabrication printers to avoid any Trademark infringement.

Stratasys also own the patent on the Fused Deposition Modelling technique (the technique was invented by Stratasys co-founder ScottCrump). It only expired in 2009, which was actually after the RepRap project started in 2007

So it would seem patents don’t stop people from experimenting with a new kind of mechanical husbandry in their sheds. Breeding and evolving a new kind of machine that can replicate itself and other things. Welcome to the future, and it is awesome.

I take requests! If you have a question about 3D printing, fire it across and I will see what I can do.

Search for the trademark ‘FDM’ at the United States Patent and Trademark Office.


On twitter, plaasjaapie corrects me that the RepRap project started on irc in 2004. plassjaapie also suggests that FFF was targeted because the group knew that the patent was due to expire soon. The tweet stream about nuances around the patent issues is fascinating, check it out. In other news, I think this blog really needs comments.


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