Question for our plastics or molding experts - epoxy casting molds

I'm working on a job where we are epoxy encapsulating some electronics.

My question - what to use for a pilot production mold?

Option 1.

--------- Aluminum CNC cut pockets Dowels adjacent recess to locate frame that aligns electronics to

Reply to
A2
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I would try UHMWPE. It will be almost as good as Teflon as far as getting the mold to release the part. And it is quite a bit cheaper than Teflon. I would think it would be good for production molds.

Dan

Reply to
dcaster

The machining marks (undercuts) will make the part want to stay in the mold even if it doesn't stick. Polishing will be a lot of work. If the mold material is rigid then be sure to have a healthy draft angle (maybe 4 degrees or more).

--sp

Reply to
Spehro Pefhany

Thanks, I'll chase up a sample of UHMWPE and do some adhesion / release tests.

Reply to
A2

I'm starting to think aluminium might be the best as we know we can get a polished finish. Not so sure we can get this with UHMWPE.

I was wondering if aluminium molds are routinely coated with something like that used on non stick fry pans.

Reply to
A2

You might try UHMWPE anyway. You have to have very sharp cutters and take off about .1 mm on the final pass. And you may be able to flame polish the UHMWPE. Unfortunately flame polishing oxidises the surface and that is not good for releasing the part from the mold.

UHMWPE is a lot cheaper than aluminume, so it might work out. You can find heaps of posts about using PE for molds on the internet all posted by people with more experience that I have.

Dan

Reply to
dcaster

"Bob La Londe" wrote in news:n1e0e1$nsd$ snipped-for-privacy@dont-email.me:

Polyvinyl acetate = Glue Polyvinyl alcohol = Mould release

Reply to
Ian Malcolm

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