Selecting then testing polymer for life time exposer to high temp
Selecting then testing polymer for life time exposer to high temp
(OP)
I am looking for a material to over mold a PCB, there will be a clear PC lens on top, a PVC supporter (with lens captures PCB in the mold) and 2 nylon wires that run through the part. Size is approximately 2"L x .8"W x.25H" We have used a TPE but when exposed to 90C temperature the material on the top surface cracked and started to pull away, it looks like it is drying out.
I now need to find a new material and need some criteria to help select the material based on datasheet information. I also need to establish some testing to validate the material will work.
We have tried to mold ABS and PA612 but the board warps and the PC lens is deformed. That was how we originally ended up with TPE. We thought about using a a TPU but the loading time off all the components is too long for the TPE and it foams in the barrel.
Any information or direction you can give is greatly appreciated.
I now need to find a new material and need some criteria to help select the material based on datasheet information. I also need to establish some testing to validate the material will work.
We have tried to mold ABS and PA612 but the board warps and the PC lens is deformed. That was how we originally ended up with TPE. We thought about using a a TPU but the loading time off all the components is too long for the TPE and it foams in the barrel.
Any information or direction you can give is greatly appreciated.





RE: Selecting then testing polymer for life time exposer to high temp
RE: Selecting then testing polymer for life time exposer to high temp
We are also considering a TEEE and a TPEE.
Do you have any suggestions on how to evaluated if the material is acceptable based on a data sheet. We relied on the contract assembly house to select the material last time. Now my boss wants me to select the material and prove it should work before shooting parts.
RE: Selecting then testing polymer for life time exposer to high temp
You do know that often, the plasticisers in PVC can migrate and solvent stress crack any PC in the vicinity.
Can you use a casting resin or two pot.
What temperature resistance does the finished product need.
Regards
Pat
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RE: Selecting then testing polymer for life time exposer to high temp
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RE: Selecting then testing polymer for life time exposer to high temp
Yes, the Sabic rep gave me the heads up on the pc and PVC issue. The two do not touch each other.
RE: Selecting then testing polymer for life time exposer to high temp
Does anyone have a suggestion on what standard tests (SAE, ASME) are done to evaluate plastic materials for high temperature?
Thank you for your time and help,
RE: Selecting then testing polymer for life time exposer to high temp
UL ratings also exist for temperature ratings of electrical components.
Regards
Pat
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RE: Selecting then testing polymer for life time exposer to high temp
There are also proprietary tests used for specific polymer applications. Like we used one where we made a film and blew a bubble until failure at a specific temperature. The film had to take a certain air pressure on a 5" bubble.