The NASCAR Car of Tomorrow (COT) program is predicated on standardization of the chassis and body elements of the vehicles (see AD&P, May ’07; Inside NASCAR’s Car of Tomorrow). Which begs the question: How does NASCAR know that the cars that are being built meet the specs? They do so through the use of a coordinate measuring machine (CMM) system. The system at the NASCAR Research and Development Center in Concord, NC, uses two GridLOK systems from ROMER Inc. (www.romer.com; Wixom, MI); a ROMER seven-axis INFINITE articulating measuring arm and probes; and PowerINSPECT software from Delcam plc (www.delcam.com; Salt Lake City).
The GridLOK is a locating system for measurement. It includes 5/8-in. diameter conical seats that are flush mounted at 3-ft. intervals in a steel plate that’s placed on the floor of the inspection facility. The measuring area is 13 x 20 ft. The measuring arm is mounted on a mobile base and has a measuring volume of 12 ft. To determine spatial coordinates, three of the conical seats touched by the probe are fitted to the measuring arm. When the portable CMM is moved to another location, this is repeated, and the measuring accuracies are maintained because the data required is relative to the part origin. The measurement sequences that is used was developed by Dan Kurtz, design engineer at NASCAR, with the PowerINSPECT software. A chassis is placed on the GridLOK measuring area, the coordinate system for the chassis is determined, and then measurement commences, starting at the front firewall, and including the intrusion plate, floorboard, fuel cell walls, oil casement, frame rails, transmission tunnel, and driveshaft tunnel. Chassis measuring for certification takes 90 minutes or more. Those that pass have 10 RFID chips attached that record the serial number and other data relating to the chassis; these tags must be in place for scanning at the race.
The NASCAR facility measures an average of four chassis a day.