Open Source 3D printing: an Interview with Josef Prusa

By on February 5, 2013


As you may know, Josef Prusa is among the most important contributors of Rep Rap project. Prusa Mendel, a simpler, easier to build variation of Rep Rap’s Mendel printer. Josef Prusa is famous for his dedication to the openness of Desktop 3D Printing, his post, “Open Hardware Meaning” and his Occupy Thingiverse, in late 2012 when we all discovered that the newest Makerbot, the Replicator 2, was going to be closed source, hit the news.

As also our 3Drag printer bets on the Rep Rap ecosystem and we are big fans of Joseph’s work, we decided to give him an interview!

Here’s it for you to enjoy!


[Open Electronics]: Ciao Josef. Would you present yourself first to our readers?

[Josef Prusa]: Hello! My name is Josef Prusa, I live in Prague, Czech Republic. But I originally come from remote village called Sedletín :-) I’m 22 and I’m RepRap core developer.
I love hardware hacking and making people realize, that they can modify stuff they own or create completely new ideas. Generally busting consume life we live now :-)

[Open Electronics]:What are the reasons behind the creation of the Prusa, how did you ended up working on this project and what are your next projects?

[Josef Prusa]: Long time ago I was trying to build original Mendel and it took a horrendous amount of time. I never finished it. I tried redesigning it (ed: as said, Prusa Mendel essentially is a simplification of Mendel) and people loved it. Soon it became the most used RepRap variant. I am really proud of that. Sometimes it still feels very surreal, you know, it took almost a year from my design to get a chance to finally see someone with my printer in real life :-)

[Open Electronics]: What’s next in 3D printing and in digital fabrication? Is it true that somehow we are going to have almost a duality between data and reality? (eg: with molecular printing)

[Josef Prusa]: Trying to predict what new stuff will be happening in 3D printing is impossible and I won’t make fool of myself. Only thing I’m sure about is that it will eventually become much more user-friendly, loads of developers are working on user-friendly SW. For example look at Slic3r by Alessandro Ranellucci, it is the biggest break-thru in user friendly-ness till the Prusa Mendel. We now have easy to build printer and easy to use software.

[Open Electronics]: How much of this innovation will be a top bottom process – eg: those driven by MIT CBA or other research centers – and how much instead shall rely on DIY innovation?

[Josef Prusa]: RepRap is very very special, because most of the innovations are brought up by regular people, not from research centers or universities. No research center with its bureaucracy can keep up with crowd-development RepRap employs.

[Open Electronics]: Openness, Collaboration: what’s their role? What’s the difference you’ve seen between Reprap evolution vs closed source printers?

[Josef Prusa]: Both are very important and without it, RepRap would not exists. That applies for every open source project. Biggest difference between RepRap and closed source printers is marketing. I mean marketing full of bullshit :-/ I am very sad every time I see a closed source RepRap derivative claiming impossible properties and talking bad stuff about “hobbyist” 3D printers :-(

[Open Electronics]: There’s some importance in building machines that are self buildable replicable.
The idea that I can build a Prusa on my own, by printing parts and sourcing local materials, is powerful. And we shouldn’t focus on the printer itself: all is going to follow this rule as Open Source Ecology shows.
In the decentralization of production what’s the importance of a design that goes towards easy sourcing of materials?

[Josef Prusa]: Right now RepRap consists of many designs, some of them are more replicable, some less. I personally design printers with printed parts only where it makes sense, I don’t try to push it too hard to 100% self replication. 100% self replication is not very practical right now in order to make RepRap more widespread. I heavily employ use of so called vitamins (readily available parts) to make it quicker to build RepRap. If you for some reason need to build printer which really uses printed part instead of $1 threaded rod and you don’t mind printing that single part for multiple hours, wasting a loads of time and electricity you can do so. There are Mendel variants with 100% printable frame for example.

Thanks Jo Prusa!
and if you liked the post please follow @openelectronics and @meedabyte on twitter.

About Simone Cicero

Simone Cicero is a blogger (at, strategist & speaker. Simone is also a long time Open Source advocate and Open Source Electronics editor. Follow him on twitter at @meedabyte