Difficulty with dealing with Plastic Creep

[federernadal]

Hello,

One of my projects is to have a plastic mount support a motor system in a hot environment (150F). However, after a few days or so the plastic mount deflects excessively (possibly due to creep) and the mount has problems due to interferences. I am having difficulty with predicting and reducing this plastic deflection.

My questions:

1) If a lighter motor is used (lighter load supported by the system), will the final plastic creep flatline at a lower point?
2) If the plastic mount design is beefed up, and in FEA the improvement in deflection is 35%, will the final plastic also deflect 35% less? I am not modeling any creep in FEA, so is it safe to assume that any improvements in static structural simulations will proportionally transfer in real life (after creep)?

Thanks!

 

[RicardoSantos188]

Hi federernadal,

I think you would need to look at the type of plastic you are using first before considering using a lighter motor because it seems that the environment that you are in ad the heat of the motor must be also a contributor to the creep failure of the plastic mount.

Look at PTFE (polytetrafluoroethylene) which is a soft, low friction fluoropolymer with outstanding chemical resistance and weathering resistance. PTFE is stable at temperatures up to 500oF and it is often used in high temperature environments or ETFE.

Kind regards,

Ricardo.

 

[Pud]

PTFE is very poor for creep. A glass filled nylon 6.6 would be better and much cheaper too!


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