A GR&R study is a useful indicator of the tester’s accuracy and the amount of variation the tester may be introducing into the process when performing Rockwell hardness testing. Even though GR&R evaluations in Rockwell testing are not always possible, once these issues are recognized and taken into account, GR&R assessment offers helpful process information. It is relatively simple and error-free to assess the GR&R performance of many different types of gauges, such as micrometres and callipers (using a gauge block of a known value to make repeated measurements on the same block and calculating the repeatability).

A GR&R examination on a Rockwell tester, however, presents unique challenges. For instance, a major barrier is the variance in the test sample because a Rockwell test is never conducted in the same area. As a result, a variation is introduced because no material has hardness that is fully uniform.

NextGen’s Universal Hardness Tester for Vickers / Knoop, Rockwell and Brinell has the Rockwell repeatability of 0.5HR.

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