Over the past 30 years, one of the most important changes in metrology has been the development of portable measuring devices like arms or laser trackers. This has brought inspection right into the production line, as close to the part as possible.
Far from the comfort of metrology labs where qualified inspectors operate digital CMMs (and their heavy, stable granite table), portable measurement is still facing major issues:
- vibrations generated by production equipment (machining centers, presses, carriage equipment);
- operators’ varying experience and skills levels.
Vibrations are transmitted to the measuring system and the object being measured. A study conducted prior to installation of a CMM in a factory operating stamping presses measured vibrations of up to 0.2 mm with a frequency of 17 Hz at a distance of 15 m from the press. Because it was fitted with the TRUaccuracy technology (and resulting self-positioning and dynamic referencing functionalities), the measuring device remained continuously locked to the part by an optical link through the measurement process. To test the TRUaccuracy performance, an experimental setup was used to expose a measuring arm and a HandyPROBE to the same level of vibrations.
Without vibrations, results yielded by both the arm and the optical CMM were similar, while the results of the measurement with vibrations clearly show the advantage of dynamic referencing and no noticeable degradation for HandyPROBE compared to an error increase by a factor of 3 for the arm.
The CMSC’s 2011 study entitled How Behavior Impacts Your Measurement includes a compelling and detailed analysis of operator behavior in the metrology process. One of the study conclusions is that human error is a major factor in poor quality measurements.
Creaform’s Portable CMMs make measurement more reliable and less operator’s dependent. It makes it possible to measure directly on the production line, thereby ensuring greater reactivity during production increases, earlier detection of potential drift, and faster identification of underlying causes.
Read the full paper presented at CMSC.