"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.


I was recently asked to quote a job like this although they used a different
material than epoxy and injected it. PVA mold release was used. Teflon
pins, and silicone o-rings protected display screens, harness sockets, and
mounting holes. Aluminum makes a decent mold for this sort of thing, but
because its rigid you do need to do a little planning to make sure your part
will demold ok, like tapered sides, etc.

I've cast other resins in aluminum molds and one trick I like is to stick
something in the sprue to use as a leverage pin to help get the part out of
the mold.

There are commercial hot glues (not your craft store sticks and guns) that
are used for this sort of thing also, but I've not used it.






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.