I am wanting some help when it comes to 3d printed mold making. (the printing and the design part) If any one is interested in helping me I would greatly appreciate it. I have not done the 3D study yet so hopefully someone that has printed before has some expertise in the matter. Thanks.
IDK anything about the mold making from the 3D prints, but I have some questions that might help you determine if 3D printing is the right approach.
What sort of application will this be for? One-, two- or multiple-part molds? How important are precision and squareness?
I ask this because if you’re making, for instance, a simple mold of a curvy flower and it doesn’t matter if it shrinks a little bit (or unevenly), then 3D printing might be a good solution. 3D printing is not going to be a good solution if you need machined part tolerances, or squareness, or mating parts like a punch and die - unless you have the ability and willingness to machine the molds after printing.
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I have done some 3D printed molds for urethane and silicone wheels. It is pretty straight forward this video is a good example:
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Don’t know if this is what you’re looking for, but…
I use a 3D printer to create the first positive (the blue thing) and a 2-part silicon product to make a silicon mold (the red thing) that I then use to cast pewter medalions.
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I have made a few silicone parts, like a tomato-shaped mold for soapmaking. (I’m actually looking to make more things pretty soon.) Nowhere near Frank’s level of professionalism, I didn’t bother with consistency, really careful mixing, or degassing. I discovered a few tricks, though.
At home I have a resin printer, not filament. It lends itself well to finely detailed models, but it’s possible to get precision parts out of it too. I typically draw up the pattern first, use Boolean operations to take a negative in a mold part, cut that into pieces, and print them out. (The shorter in height the better, I suspect, to reduce distortion while printing.)
Silicone is apparently quite picky about stuff. It doesn’t like uncured resin, it doesn’t like rubber bands, and it doesn’t like gloves. If any of it finds any of these, none of it will harden. I have used both Elmer’s glue and two-part epoxy to bond and seal my molds; the epoxy is good only for one-offs, as it grabs onto the resin tighter than the photocure does, and Elmer’s can pry apart but will run on contact with silicone. No idea why. I spray the inside of my molds with an automotive lacquer to protect against any trace of resin, followed by a silicone release agent to help get it out once it hardens.
My particular approach lends itself to leaks and messes, so I leave tight-fitting seams in the molds. I can’t speak for all resin printers, but mine tends to print 0.005" big on a side (0.010" big for diameters). SolidWorks has useful surface tools to shrink parts by 0.005", but with other modeling tools I have to be careful to leave enough clearance between parts. I’ll also be careful to leave the pour in a box, a cup, or something else to catch leaks without getting on everything.
I am very much an amateur in printing and even more so in casting, as I have like a 50% success rate, but it’s getting better as I pay more attention to detail. Take my advice with a grain of salt and maybe an Aspirin.
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