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. To avoid delays, fixturing requirements should be well understood and addressed while a project is still in the planning stages. Even long after the equipment has been commissioned, many machines continue to be underproductive and cause backlogs in the inspection process, which is a direct result of inadequate fixturing.
Historically, fixtures were designed and built as if they were gages. Inspection equipment was often manually operated and not programmable. The software used to control it was not as capable of processing the information as it is today. Fixturing was designed to present the part to the probe head or camera in the most efficient way, and multiple stations were frequently required to access all critical features. Fixtures were also expected to position a part to all of its primary datums, which would often require a complicated design. Over the years, CMMs, vision and gaging systems have become more sophisticated and less dependent on overly complex fixturing. Advances in the machines and software have allowed inspection equipment to measure parts more quickly and more intelligently. Fixturing is now facing new challenges, yet remains key to the success of any inspection.