Notch preparation

Rubber World, April, 2007

Notched impact bending tests are performed mainly in accordance with the Charpy Standard ISO 179-1 or Izod Standard ISO 180 or ASTM D 256, and specimens must have a prepared notch of type A, B or C in accordance with the relevant standard, according to the company. The requirements for the performance of any notch milling machine with regard to the cutting and feeding rate are specified in ISO 2818, because differences in the notch production process can have a significant influence on notched impact strength results, according to the manufacturer. The company has introduced a notch milling machine, ZNO, to handle packs of up to 12 ISO specimens which can then be notched at the same time. The independent settings for cutting and feeding speed allow optimum notch results for each material, while the solid machine construction and direct notch depth adjustment system enable an extremely high dimensional accuracy over the complete pack length, according to the manufacturer. During the development of the product, special attention is said to have been paid to the operational safety features. (Zwick GmbH)

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