Plastic with a close static to dynamic coefficient of friction

Without spending hours searching data, I was wondering if anyone could recommend some plastics that have a close static to dynamic coefficient of friction.

Teflon filled Delrin says it has a close match around .19, and it would be better if the coefficient was higher. High temperature would be nice too.

Any other plastics come to mind?

higher or smaller? Smaller is less friction. How much temperature do you need?

Tom

Sorry, more friction... >.19 and not melt or fail while absorbing friction heat energy.

Quadrant makes a special grade of Nylon called Nylatron 703 XL that has nearly the same static and dynamic coefficient of friction. It was made specifically for low stick-slip applications. Unfortunately it has a lower CoF of .14.

Usually, when you want low stick-slip you also want low friction. What you're looking for is a bit unusual.

Have you looked at PEEK?

laminar-flow said:

Without spending hours searching data, I was wondering if anyone could recommend some plastics that have a close static to dynamic coefficient of friction.

Teflon filled Delrin says it has a close match around .19, and it would be better if the coefficient was higher. High temperature would be nice too.

Any other plastics come to mind?

Click to expand...

Against what? Steel? Itself?

In fishing reel brakes close to identical static vs dynamic friction is also preferred. AFAIK these typically use stainless steel vs. PTFE/rulon/graphite.
All of them have low coefficient of friction and stack of disks is common solution.

Stainless steel vs. graphite would solve high temperature part..

Either a stacked arrangement might work if you can only find low CoF materials with the desired ratio. Two parts, each comprised of a identically sized stainless and rulon rectangles with a smaller spacer, repeated as many times as necessary. The two parts would interlock. With the spacer of the right material, you could use the bolts holding the assembly together as a frictional adjustment. This is a linear implementation of MattiJ's idea. The more energy you have to dissapate, the more layers of this you could use.

If the heat generated is significant, perhaps a non-stainless (higher thermal conductivity) steel would be better.

If the amount of heat is really significant, perhaps a dashpot (like a shock absorber)?

You indicate that this is an oscillating operation. Generally, oscillations start with a rotary motion (e.g. a motor). You might consider braking the system in the rotary motion portion of the mechanism.

Last idea, you could implement magnetostrictive braking. That would be cool.

All good points. The application is linear inside of a tube. Like an expanding collet. The other material is not defined yet. Probably Stainless. Eddy current damper is also being investigated but there may not be enough room for all the magnets.

IIRC a company called Tribco makes kevlar based friction materials for clutches. You might ask them

might look into TORLON PAI material . you'd best be sitting down when you price it .
not slipppery , and good to 500F .

red beard said:

Quadrant makes a special grade of Nylon called Nylatron 703 XL that has nearly the same static and dynamic coefficient of friction. It was made specifically for low stick-slip applications. Unfortunately it has a lower CoF of .14.

Usually, when you want low stick-slip you also want low friction. What you're looking for is a bit unusual.

Click to expand...

They make it, but only in flat stock. They don't do round bar.