A CMM can tell that a part is out of spec, but that’s just a symptom and rarely provides enough information to identify and correct a problem. The standard first question is “Is there a trend; will this be an ongoing problem?” An ideal reporting system can help answer this question. Use this 7-point checklist for guidance.
When purchasing coordinate measuring machines (CMM) and vision or flexible gaging systems, fixturing is often overlooked until the inspection equipment has been commissioned and the first parts need to be measured.
Precisely measuring and validating parts made from low-density materials such as plastic can be tricky and time-consuming. For example, silicone parts readily bend and flex, leading to inaccuracies. Fixturing, the traditional solution to immobilize and align parts for measurement, is a lengthy process involving engineering, construction and validation of the custom fixture.
Work holding fixtures for inspection devices have evolved over time and now have become, in some cases, as complex as the parts they are designed to hold. There was a day when some 1-2-3 blocks, knee blocks, double-sided tape and hot glue were all you needed to fixture parts for measurement on a coordinate measuring machine (CMM).