wooldog
Mechanical
- Oct 9, 2006
- 1
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?
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?