On 4/11/2015 1:56 AM, Carl Ijames wrote:
"A2" wrote in message
...

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 0.5mm
Release coated mold - PTFE / Teflon?
Use release agent? Hope to avoid.


Option 2.
---------
Plastic mold
CNC cut pockets in a ~30mm thick slab
Dowels adjacent recess to locate frame that aligns the electronics.
Is there a plastic that epoxy won't stick to - no release agent needed?
Nylon? UHMWPE? Maybe $$ Teflon?
I imagine a silicone or urethane mold may not be rigid enough.

Any suggestions? Recommendations?
Thanks!



Background:
Prototypes have been cast in a mold made from epoxy and a aerosol mold
release used. It works ok, we ended up making the mold 2 parts as the
completed parts were a little hard to remove.


*The electronics is sat into a 130mm x 50mm x 20mm (5"x2"x3/4") mold
*Their is heaps of draft on the mold for easing release.
*Epoxy poured into the mold.
*After 24 hours they are de-molded.

*These will be made in batches of say 30 to 100 at a time.
*We are happy Doing say 6 at a time with a 24 hr turn around.
*Mold may be 6 units wide or 6 individual molds
================================================== =============

I've never cast epoxy, just polyurethane and a little silicone, in aluminum
and polyurethane molds, but my guess is that polyurethane rubber would work
well. I would go to www.smooth-on.com and first read their tutorials and
then give them a call. I've been very happy with their support and
products.

-----
Regards,
Carl Ijames
.



Thanks Carl, I'm a bit worried about using a mold with any flex as we
have to easily locate the encapsulated electronics to 0.5mm which we
were hoping to do by mounting it to a frame and have it located by
dowels on the mold.