Flex circuit molded into plastic cavity?

[RBUD]

Can a flex circuit withstand this?
Proposed design: flex circuit 'sandwiched' in plastic housing. Subjected 2 times to temperature of 320C (608F) in a mold cavity for prolonged period - possibly a minute to cure plastic (Lexan GE #940). Any feedback appreciated.

 

[nbucska]

I suggest posting this at "Plastic Engineering" (Forum 712)

Plesae read FAQ240-1032
My WEB: <

http://geocities.com/nbucska/>

 

[MikeHalloran]

I'd be surprised it it withstood one shot, let alone two.

Maybe you could support it by the conductors. If you brought all the conductors out to the edge, and had eyes in the ends to mate with pins in the mold, and all the conductors were straight like little tie rods, maybe you could get away with it. You'd have to trim off all the dangling eyes, etc as a secondary operation, and be careful about not leaving any on the mold for the next part.

I'd call it a high risk, high cost experiment...



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Yeah I'm with Mike here..

What about jigging the wire paths in and using the injection media as the "cable housing"?

You realize that IC makers run injection plastic thru the forest of microscopic 60AWG(?) gold wires that are bonded from the lead frames to the ICs billions of times a day without breaking the bond wires.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[MikeHalloran]

ICs are encapsulated in epoxy, not Lexan. The flow is of a very different viscosity.



Mike Halloran
Pembroke Pines, FL, USA

 

[itsmoked]

Yeah I bet.. The temp seems to be too.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[lighterup]

I have used polyamid boards downhole at 200 degrees C for many hours without any problems. The thing that was the problem there was the solder, if we happened to go through a zone which exceeded 200 C for very long.
I have also done an embedded cell phone antenna on a polyamid flex circuit which was molded in an ABS sandwich. I do not believe the cure temperature was as high as you describe, though. Do you really need to use lexan?