Rubber Deflection Tests in Compression per ASTM D575 & ISO 7743

ASTM D575 method A helps determine rubber deflection in compression. ISO 7743 helps test for compression stress-strain properties of vulcanized or thermoplastic rubber using a standard test piece with the metal plates lubricated; metal plates bonded to the test piece; using a product or a part of a product with the metal plates lubricated. For well-specified product shapes, such as O rings, the result may be correlated to the hardness value. The methods are not suitable for materials that exhibit high set. An application engineer can assist in the selection of the best grip and jaw face for rubber tests. Pneumatic air grips with serrated or rubber coated faces are common. A constant gripping force can prevent specimen slippage when specimens elongate. Self tightening grips, such as roller grips, are also adequate for rubber tests.