The effect of time and other environmental factors on fiber optic polishing rubber pads

Domaille Engineering has just completed the first phase of our extensive testing of rubber pads used in the fiber optic connector polishing process.  The original testing process started with several customer inquiries into the effects of durometer change on the polishing process.  The first task for our engineering team was to understand how to accurately measure durometer.  After testing all brands of rubber pads including the Domaille brand, we found that on the average, pads varied up to +/-10% from the durometer marking on the pad.

Our engineering team worked with industrial leaders in the manufacturing of rubber and select customers within the fiber optic polishing community to correlate equipment and individual readings of different durometers to ASTM D2240 specifications in different environmental factoring including humidity, temperature and time. Through this calibration process, Domaille was able to achieve consistent test results within half a durometer for all durometers tested.  Overall, Domaille was able to produce rubber pads to within +/- 2 durometer for all ranges of pads. 

Of the environmental factors, humidity had the least effect on the rubber.  Temperature did change the durometer readings, but it was fairly small percentage in normal operating ranges.  One of the really interesting finds was the effect that time played in the results, especially on the lower durometer rubber pads.  The fiber optic polishing leaders that were using the calibrated test pads noticed that their end face geometry was slowly changing over time.  The calibrated samples that were originally tested at 60 durometer measured 7% higher and 70 durometer pads measured 5% higher after only eight months time.  The higher durometers also changed, but by a lesser percentage. 

To address these changes, Domaille Engineering created the Gold Series rubber pads.  These pads have been tested using calibrated test equipment and the actual tested durometer is marked on each pad along with a date that the pad was manufactured.  Domaille also color coded the pads for easy identification of the correct durometer.

Using the Domaille Engineering APM-HDC-5100 or 5200 fiber optic polishing machine, the beta testing organizations actually created dozens of different fiber optic polishing programs to correlate to the actual known durometer of pad and to account for the change in durometer over time.  As the rubber pad durometer changed, they changed the polishing process to match the new actual durometer (not the original labeled durometer) and achieved virtually no variation in their end face geometry data.

Further testing is ongoing for the effects of polishing pressure on the rubber pads and also how the variation in polishing media affects the polishing process (measuring durometer through the polishing film). 

For more information on the rubber pad testing, please contact me at dhickerson@domailleengineering.com or call (507) 281-0275, ext 120.