Rulon (PTFE) Experiences?

[lukewarm]

Has anyone used Rulon bearings in a CNC machine?

I've been doing a bit of research and Rulon sounds like a dandy material. Kinetic and static friction are very near the same (no slip-stop chatter) and the coefficient of friction is very low. Also it handles a huge amount of pressure and isn't subject to cold flow. I priced out some cold finished 2" shafting and it's very cheap (100$ for 6 feet) and the bearings themselves are a few dollars a piece. Anyone have any experience with Rulon or any other PTFE? I think it would be a good choice for my z-axis!

Thanks

[RICHARD ZASTROW]

Rulon and other PTFE "plastics" have been used for years on sliding way surfaces on machine tools.

Can be "scraped" and "flaked" similar to traditional cast iron surfaces.

My experience with Rulon etc. has been very positive, especially on flat surfaces. I'm not familiar with it being used on round surfaces for sliding or rotating motion.

Dick Z

[lukewarm]

Thanks Richard! Do they compare well to roller type bearings friction-wise or should I consider them a bit less efficient (for my stepper sizing calculations).

[RICHARD ZASTROW]

The "plastic" way systems have less friction and stick-slip than plain metal slide surfaces. However, they have far more friction than ball or roller guide ways.

The plain ways whether "plastic" or metal, when properly sized, can carry more weight but at lower speeds.

It is, as usual, a trade-off. The manufacturers of rolling bearing type way systems usually publish the formula for force required to move a load. Generally this is in the tech sections of their on-line catalogs.

Dick Z