Training Trends:<br>Evaluate Your Coordinate Measuring Machine
The use of coordinate measuring machines (CMMs) has moved from the laboratory to the shop floor, and increasingly, from large factories into small job shops as well. As a result, there is growing demand for information on ways to evaluate the performance of CMMs, as an aid to making the best purchaing decisions.
One method to evaluate CMM performance is to conduct a gage repeatability and reproducibility (GR&R) study. GR&R studies focus on identifying and eliminating measurement variation caused by out-of-calibration gages, environmental conditions, methods or procedures and appraisers, commonly referred to as operators. By using GR&R studies, measurement variation can be identified and reduced to produce more precise measurements. Ultimately, reducing measurement variation results in a greater ability to differentiate between parts that are in or out of specification. Measurement variation adds to the total variation seen when products are assembled, and this variation makes a manufacturing process appear less capable.