Indentation Hardness

For vehicle seats and mattresses, indentation hardness is one of the most important characteristic values used to describe the quality of, for example, seat comfort. These shaped parts are usually tested to DIN 53579-1. For the seat cushion test the specimens are placed in specially shaped molds.

For larger shaped foams Zwick has developed a C-shaped load frame allowing good access on three sides. For mattresses a positioning stage is also available with which the mattress can easily be moved to the desired testing position. For testing smaller shaped parts or carrying out tensile tests the side support plates can be folded down.

State-of-the-art testControl measurement and control electronics enable adaptive travel and force control functions. This is particularly advantageous for hysteresis tests and in determining the ‘comfort value’ to Volkswagen PV 3410, allowing cycle end positions to be achieved precisely and at constant speed.

Testing of slab foams is standardized in ISO 2439 and ASTM D 3574. The specimen size of 380 x 380 mm allows the use of Zwick standard machines which are equipped with load frame stiffness compensation, providing very accurate measurement of indentation hardness.

A complete program library is available for testXpert software, covering all relevant DIN, ISO and ASTM standards. There are also a large number of ready-for-use Standard Test Programs produced for in-house standards of automobile manufacturers including the Volkswagen Group, DaimlerChrysler, BMW, GM, the PSA Group, Ford and other well-known companies.