Overmould / insert mould onto Flexi-PCB

[marvincooper]

Hello,

I have just started on a project where I will need to produce a flexible (probably silicone) housing around a flexi-rigid PCB, a lithium battery, LCD and a button.

The product is highly cosmetic and worn next to the skin. The housing needs to hermetically seal the electronics.

I am looking into manufacturing methods and could use some advice please!

Current thinking is this:

Encapsulate the electronics assembly, including the battery and display. This would be potentially be by low-pressure injection moulding with a flexible resin. I am not sure how compatible the flexi part of the PCBA will be to this process, what considerations I need to be aware of?

The encapsulation will also include 2 rigid plastic parts which will form part of the housing.

The encapsulated sub-assembly will then be over-molded with silicon (or similar flexible resin) to provide the cosmetic finish.

My questions are –
1. Can you encapsulate a flexible PCB and retain flexibility?
2. What pitfalls are there?
3. What alternative approaches should I consider?
4. What suppliers have experience of this kind of product and construction?

Any advice much appreciated.

 

[justwrong_44]

If you over-mold with silicone or TPE it will remain flexible, but will be a little stiffer than is was before molding. You can improve this by using radial ribs like some cell phone or head phone jacks.

What temperature can the flexible PCB and sub-assembly part withstand?

When over-molding; bonding could be an issue.

What materials are the plastic 2 parts?

Jim

 

[peterc]

I would also be very interested to hear your ideas as I have a similar problem and am looking for a means of encapsulating a flexible circuit board/li po battery

 

[David23Kipp]

I was just browsing for relevant posts about PCB and I happened to stumble upon yours. Thanks for the useful information!