Changing material from PEI to PBT

[dans95]

I have been assigned the task of looking into the feasibility of changing the materials of some parts which are currently made of Ultem (PEI) to Valox (PBT). Ideally we want to do this with minimal change to the tooling. Anyone have experience with these materials?

 

[patprimmer]

They are very different materials with very different properties and very different mould shrinkage.

I presume you already have access to the moulds, so the easiest first step would be to simply do a moulding trial in PBT and see what you get.

Regards

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[plastx]

GE Plastics produces both ULTEM and VALOX so they should be helpful. Unfilled versions of these materials will produce very different dimensions. Highly glass filled versions will be closer especially if the wall sections are on the thin side. It will still be a challenge if you need the dimensions to closely match.

I'd agree with Pat (as always) to try out some parts as a first step if you have already reviewed the critical properties and VALOX meets your requirements.

Mike

 

[dans95]

Thanks. I had heard from another source that by varying the % of glass fill you can tailor the shrinkage rate to some degree. I'll see if I can contact GE platics and get enough info. to start a proto run.

 

[patprimmer]

I would contact a few other suppliers as well.

GE have a motive to "encourage" you to stay with their "exclusive" and "expensive" product.

DuPont, Ticona, BASF, ArKema (spelling?) and DSM are some that spring to mind.

Regards

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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.