Tech Talk Blog

Surface Engineering Impacts Bearing Friction and Wear

February 18, 2014

surface engineering for pipeline bearing applicationsI had a great discussion yesterday with a caller who was looking for specs on the optimal surface finish for mating plane bearings.  We reviewed the pros and cons of different preparation methods; turning vs. roller burnishing and the ideal RMS finishes needed to achieve different levels of functionality. Much of that conversation is captured in the video below; it is a great primer to very common wear and friction questions.

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Measuring Operating PV

August 2, 2011

I was recently asked to review this important measurement guideline.  PV is a means of measuring the performance capabilities of bearings.  P is expressed as pressure or pounds per square inch on the projected bearing area.  V is the velocity in feet per minute of the wear surface.

For sleeve bearings, the surface speed is Pi (π) x diameter x RPM ÷12 in inches.  P is the load on the bearing in pounds, divided by the projected area in square inches.  For sleeve bearings, the projected area is the length times the diameter of the bearing.

PV is obtained by multiplying the P x V as shown here:

               3/4” shaft @341 RPM:
               90 lb total load, bearing length 1”

               V= 3.1416 (pi) x Shaft Diameter  x  RPM ÷ 12
               Or  3.1416 x .750 x 341 ÷ 12 = 67 sfpm

               P= Total Load ÷ projected area
               Area = .750 ID x1.0 long  = .75 in projected  bearing area

               P= 90 lbs ÷ .75 = 120 psi

               PV = 120 psi x 67 fpm = 8040 PV

As long as you keep your application below the estimated PV as well as the known P and V you will successfully be able to utilize polymer bearings!

Our team of experts can help!

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Accelerated Aging: Leveraging Temperatures

April 6, 2010

Now that we've established the importance of bag selection in accelerated aging, let's move on to temperatures.

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Accelerated Aging and Product Bag Selection

March 30, 2010

Accelerated aging is a testing method that enables us to estimate the potential lifespan or shelf life of a product when actual data is unavailable. For instance, products may be subjected to unusually high levels of stress, or mechanical parts may be run at speeds far above normal. In the case of polymers, they may be kept at elevated temperatures to study the subsequent chemical breakdown.

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