Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

I've Heard It All Now

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I've Heard It All Now | 12 June, 2013

Our customer wants to do an overmold operation (3rd party to us) on the non-populated side of a rigid flex assembly. Their inquiry below:

"We are going to end up over molding plastic over the back of this rigid flex to form an enclosure but wanted to ensure that the backside (non component side) can withstand temps of 300°F of hot plastic and 18,000 PSI of mold flow pressures? Let me know if you can help me find out if this or how this can be done without frying or breaking the board."

I see the heat being a potential issue for the polyimide flex if not pre-baked. As far as the pressure, I have no idea how to respond. Any thoughts?

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I've Heard It All Now | 13 June, 2013

It sounds like they are referring to Low-Pressure molding, which was designed specifically to encapsulate electronics. I have seen some products that were processed on polymide flex, and then overmolded in this process. I would start by contacting "the experts" at Cavist Corp. A quick Google search will give you the website info.

I am not affliated with them, but I have worked with them in the past.

They should be able to tell you if your specific material is suitable for this process.

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I've Heard It All Now | 13 June, 2013

18000 psi is what a injection molding machine can produce depending on the size of machine. When doing over-molding/insert molding the machines are a lot smaller less than 1000 psi and a lot of smaller items less than 500 psi. as far as Temperature 300F is nothing think about your reflow oven temps or wave soldering temps Solder does not liquefy until 375F.

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Reflow Oven

Non-heated dispensing system