bushing selection

[wooldog]

If a plastic bushing with an interference fit is pressed into an aluminum tube that will see a temperature variance of -40 to +60C, what kind of material, press fit, and hardness would be necessary to ensure the bushing does not relax due to creep, and become loose at low temp over a product life of 5 years.
The bushing is used only as an axial retainer for a very low mass assembly and sees no appreciable load other than the compressive force of the fit. The temperature extremes will occur over a period of ~hour and will not be cyclical.
Intuition tells me a typical ABS thermoplastic with about a 2X factor of an H7u6 force fit would probably serve the purpose, but I don't have any data to support that and I wonder if a cross-linked thermoset like 90 shore A polyurethane would resist creep (or compression set) better. Any advice?

 

[Heckler]

I've used these bearings/bushings in previous designs.

http://www.afmusa.com/bushings.plastic.asp

Could you go into a little more detail with regards to its usage.

Best Regards,

Heckler
Sr. Mechanical Engineer
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[nigelt]

Hmmm, your description is quite clear, but also what is qty requirement, mfg process, any cost expectation, as well as forementioned usage details.
As a general comment for bushings subject to what could be called side-to-side hammering type impact loads, I found that machined acetal worked v.well compared to other matls - resisted creep and deformation from a ground steel pin. App was low speed & starting friction was not a concern. ~ .37ID & .50OD. Fit in housing was a light interference ( I can't remember details) but it didn't move at least not enough to notice.
Nigel