Delcam’s PowerINSPECT software proves a good fit for General Motors
Delcam’s PowerINSPECT inspection software has proved to be a good fit with the quality control requirements at leading automotive company, General Motors. When engineers at the company want to make sure that the various body panels in a car are fitting together properly, or to find out why they are not, they often turn to the Design Check and Vehicle Assessment team in the Warren Vehicle Engineering Center in Michigan. The team is equipped with the latest in portable inspection and laser scanning technology, plus the Delcam software.
Decades of buyer surveys have shown GM, and the rest of the automotive industry, that the way the sheet-metal skins of cars fit together is a huge factor in the decision to buy a given model. The Design Check and Vehicle Assessment team plays a critical role in making sure the fits and finishes between doors, door frames and body pillars, and the hinge alignments, are produced exactly as they were designed. John C. Sturgis, Design Check team liaison engineer and team leader, explains that "for us, this is all about the physical integration of as-designed parts, how they fit together, rather than focusing on the dimensional measurements of individual parts.”
The actual data are gathered as points with touch-probes or laser-scanners fitted to inspection arms from Romer Cimcore and are used to check a rectangular array of lines a few inches apart on all the exterior parts for accuracy. In addition, colour maps from PowerINSPECT are often used to show deviations from the nominal CAD model within the surfaces. "These colour maps also show whether any section of the surface is out of tolerance and, if so, how far out. Those kinds of data are very handy for stamping-die rework,” Mr. Sturgis added. What GM gets from these efforts at the WVEC is assurance that vehicle bodies are fitting together as designed and, for those rare times when they don’t, reliable and easily understood dimensional data that points to where the problems lie.
Another of the Design Check team’s biggest measuring challenges is the under-body alignment of an entire car. This is a calibration check on the body framing weld-assembly system with which the car had just been built. "This was for a global alignment of the frame, corner to corner,” Sturgis said. "Once we get the data plotted into the car-body coordinate system with PowerINSPECT,” Sturgis said, "we take the car out into the shop where we can lift it up and get underneath to measure exhaust system locations, placements of bumpers and bumper fascia, and other parts of the under-body.”