MRRF: 3D Printed Resin Molds


Visiting the Midwest RepRap Festival, you will, of course, find a ton of 3D printed baubles and trinkets. A slightly more interesting find at this year’s MRRF was a lot of resin cast parts from [Mark VanDiepenbos]. He’s the guy behind the RotoMAAK, a spinny, ‘this was in the movie Contact‘-like device designed for spin casting with resins. At the festival, he’s showing off his latest project, 3D printed resin molds.

With the right mold, anyone with 2-part resins can replicate dozens of identical parts in an hour. The only problem is you need a mold to cast the parts. You could print a plastic part and make a silicone mold to cast your part. The much more clever solution would be to print the mold directly and fill it with resin.

[Mark] printed the two-part rabbit mold seen above out of ABS, filled it with urethane resin, and chucked it into his RotoMAAK spin casting machine. Six minutes later the part popped right out, and the mold was ready to make another rabbit.

Video below.

26 thoughts on “MRRF: 3D Printed Resin Molds

  1. That’s great and it’s nice to see a kit coming out. I made a rotocaster to demo at the 2012 Pittsburgh Mini Maker Faire and to use for the same purpose (small scale mass manufacturing from 3D printed prototypes). If you have access to a 3D printer to make a few small parts, my rotocaster can be built with hand tools for about $60.

          1. It wasn’t talking about the machine in the article. It’s just a similar machine, but one you can make by hand easily. I don’t have good documentation right now but it’s something I hope to be putting together soon as more people have been borrowing my machine and want one for themselves.

  2. I really wish someone could figure out how to make a filimant to do wax printing on a 3d printer to do lost wax casting of parts. IT would be uber cool if you could take a $300 printer and do metal casting in your own garage (Yes a forge is trivial to make)

    1. While they have dome work on using other materials in 3D printers, plastics just seem to work the easiest.

      A round about way is to do this, make a wax casting, then make a metal lost wax mold. Still it doesn’t seem like a bad process.

    2. You’d have to generate a wax filament that wouldn’t fuse together during production, shipping and handling, and would solidify quickly as it came out of the printer head. You can do this, but you wind up with a paraffin-based material that’s so close to the existing materials that it’s not worth the trouble. Has anyone tried “lost ABS?” Given that its melting point is in the 220 – 250°F range you’d think it would be possible if a bit slower than “real” wax.

    1. Urethane casting resins tend to stick to just about anything except for silicones and non-polar plastics like polyethylene and polypropylene. If the surface of silicone has become deteriorated and roughened a bit, urethane resins can manage to stick to it so well it cannot be removed. I’ve had a few molds where that’s happened, destroying the mold despite release agent.

    1. I don’t see the comparison. Simplier… yes, less effective…yes. The instructable one is human powered. The RotoMAAK is motor powered. Are you going to hand crank molds over and over again, or even for a few hours for the clear resins and a perfectly consistent speed?

      1. Sure, but you could motorize this solution as well trivially. Depending on how inexpensive the RotoMAAK is and whether it’s open source or not, it may be worthwhile, but in terms of something makers may want to make, it’s good to know the different ways of going about it.

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