Tech Talk Blog

The life expectancy of filament wound composites like TriStar’s CJ product can be improved by understanding some of the typical failures. One consideration is the shaft material. In some applications where the motion is oscillating and at variable frequencies, the bearing can experience rapid wear. This is caused by small angle oscillation or small amplitude vibration and the resultant fretting corrosion. The wear debris that occurs can quickly become an abrasive that dramatically shortens life.

There are a couple of possible fixes for this problem. First, consider going to a 400 Series stainless pin. Testing by an independent company showed a 26 times improvement in wear life by making this simple change. The improvement was directly related to the elimination of the fretting corrosion that occurred on the 1215 carbon steel pin used before.

A second fix is improving the shaft finish and hardness. Another test showed that by going to a 50-55 Rc hardness on the shaft and improving the surface finish to 4-6 rms extended the wear life of an application from 500,000 cycles of life to over 1 million cycles.

One thing to look for if you are experiencing rapid wear of composite filament wound bearings is the debris. If the debris is a fine brown powder than the wear is normal. If the debris looks more like shavings or accumulates in large clumps on the shaft, then you may have a shaft material, surface finish or pin hardness issue that needs addressing.

That being said – CJ bearings are crucial for transportation and other roles. Find out more in our Shooting Star Archives!

Recent studies have proven beyond question that the surface finish of the mating hardware when using composite bearings will make or break the performance. In a rotary test, the 8rms mating surface finish had a wear rating of 1, at 16rms it increased to 1.4, 32 rms 2.2 and at 63 rms 5.3. It was also noted in the test that the method of finishing also influenced the bearing wear. Roller burnished surfaces performed the best with ground and polished next best. Turned finishes or mill finishes, even at 16rms, tended to have faster wear than the other finishing techniques.

And if that wasn’t enough for you – head over to the Video Learning Center and pick up a few more nuggets of information.

Rulon bearing materials, and other filled PTFE materials like Fluorosint and Ultraflon, have a unique reaction where coefficient of friction is concerned. Unlike most materials which theorize that higher loads and speeds mean higher friction, filled PTFE products are just the opposite. WIth these materials, the higher the load – the lower the friction. Same goes for speed as a general rule. Design your PTFE bearings with the thought in mind that surface contact area can be reduced dramatically to optimize friction properties. Remember, more is not necessarily better when it comes to PTFE based bearing materials.

Still have questions? Don’t hesitate! Ask The Experts!

Rulon 142 is an excellent material for high load, high speed linear guideway liners for machine tools. Commonly used as an inexpensive insurance policy to possible lube failures on machines, Rulon 142 is bonded to the dynamic component on the X-Y-Z tables of some of the world’s leading machinery builders. Rulon 142 is also an excellent material for rebuilding machine tools where the efficiency and tolerances have been lost over time. Easy to install using CE211 or CE211FC adhesives available from stock. Rulon 142 is commonly used as an cost effective alternate to Turcite B and is fabricated using the same techniques. For more information on Rulon 142, visit www.tstar.com and check out our Shooting Star Archives for a number of articles on Rulon and more!

TriStar’s CJ bearings are filament wound composite bearings with various liner materials for specific applications. CJ bearings are able to operate from cryogenic to +350 temperatures with NO LUBRICATION. CJ bearings are primarily for high load, medium speed linear or oscillating applications such as lift and tilt points on equipment. The FCJ and Super CJ are designed for high loads and high speeds with 400 sfpm attainable without lube. CJ bearings are truly maintenance free bearings and cost effective even when compared with bronze bushings. For more information on CJ bearings visit www.tstar.com. And don’t forget to contact TriStar to learn how CJ bearings can help with your product performance.