Identifying Important Variables in Compression Set Testing

A commonly practiced compression set test within the rubber industry is ASTM D395 Method B.  This method can be very descriptive in some guidelines, like a 0.250 µm maximum plate roughness.  However, it is also vague in many areas, as in the “approximately 25%” compression directive.  The number of allowable ranges, along with the vagueness of some of them, can lead to a higher variance in the results.  Due to the complexity of measuring some of these testing protocols, many go unrecognized or unaccounted.  This study identifies important variables and recommends methods to reduce variation in ASTM D395 Method B.