Is this to be a chronic thing? PTFE cold flows, so constant pressure or rubbing will cause deformation of the material.

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It will be chronic. Not constant, but it will have periodic rubbing over the course of 7 years. Do you have another material in mind? It would be great if it is machinable, but molded is a backup option if needed.

I don't think forces from a cable jacket laying on a PTFE surface will be enough to cause cold flow.


I don't think you'll find much difference in wear rates between different materials, even between metals and plastics provided the surface is smooth. Keeping the surface clean will help with abrasive wear, that rules out any materials that will corrode or oxidize.

Not sure exactly what your application is but you might consider an e-chain to control your cable motion like these from Igus: https://www.igus.com/info/energychains

If it's just rubbing, why not ultrahigh molecular weight polyethylene? Very slippery, similar to Teflon, but a small fraction of both the price and the environmental impact.

Quote (moltenmetal)

why not ultrahigh molecular weight polyethylene

Is there any way to calculate the life, or is there any way to determine the coefficient of friction between the polyethylene and the PVC?

I second ultrahigh molecular weight polyethylene over teflon because it's about 1000 times tougher, which means that it won't abrade. It is slightly higher in clean coefficient of friction, but that difference goes away when there's the chance for any gouging into the material, such as from dirt and grit or roughness of the mating material; pure ptfe is about as tough as cold butter and has some really great properties, but for avoiding friction I'd first look at ultrahigh molecular weight polyethylene and also acetal homopolymer (Delrin) for wear/abrasion resitence.