My boss was looking to get some vacuum formed molds made, and so he paid $150 to have some place print out 3 parts in PLA and ABS, and then have those parts used to make molds via vacuum-forming (thermoforming) of HDPE.

Well, the PLA parts started to give out after being used to make one vacuum-formed HDPE mold. The ABS parts lasted for 2 vacuum-forming sessions before giving out.

The parts were each about 4" x 8" x 10"

What's the best way to do this kind of thing without losing your 3D-printed parts on just the first or second try? He was hoping to get at least a half-dozen molds made, to try out different thicknesses of HDPE.

Use Nylon or you could also cast a filled epoxy over the model to create a more robust mold, or plug.

I used a Makerbot 2x to print out vacuum form molds at my old job. The ABS parts were solid every time I used them.

It was a homemade vacuum former and I heated the plastic sheets up in a toaster oven to probably 150C.

The key is to have the mold plastic have a higher melt temp than the forming plastic.

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greghoge.com

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Hi Sanman,

As the guys here have stated, it is not the printer itself that will make the biggest impact on the mold, but the printing material needed. It might also be important to add that an all metal hot end may be necessary for using some materials with higher melting temperatures. Some hot ends simply wont be able to handle the heat needed to bring the materials to melting temp. Hot ends are pretty easy to fit as an add on so it shouldn't influence your decision. The main factor that you should take into account, would be budget and build area. If you give us an idea of these I'm sure we can point you in the right direction.

All the best,
Kev

We`ve found it pretty easy to pour modeling plaster into thermo-formed sheets, to make a plaster mold. We`ve been able to use those plaster molds to make even more thermo-formed sheets over and over, because the plaster pieces don`t suffer from any melting due to exposure to heat.

So I thought it might be easiest next time to 3D-print some negatives of our 3D model. Then we could pour the plaster directly into those 3D-printed molds. Then we could use the resulting plaster pieces to make as many thermo-formed sheets as we want, since the plaster will stand up to the heat repeatedly.

But then someone asked me if pouring plaster into a 3D-printed mold will allow the plaster piece to release easily later on. I don`t know - is there any kind of sprayable Mold Release Agent for plaster that would be compatible with PLA or ABS?

If anybody has any prior experience on this, I`d appreciate a reply. Thanks.

Standard mold release should work.

If not then one specifically made for plaster should do fine. You can check out smooth on. They have some pretty good stuff.

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greghoge.com

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just a little olive oil !!