The system then generates the part program with the necessary positioning and probing instructions. Off-line part programming is recommended so that the measuring machine is not diverted from its real task. Servo wrists can be fitted with extension bars for inside car body inspection with no loss of accuracy. Software compensation routines are available to ensure probe positioning accuracy without calibration. Thin-walled parts need to be held in their nominal geometry during inspection.
Dedicated fixtures are a possibility.
But they tend to be complicated to design, time-consuming to manufacture and maintain, and costly. An alternative is the flexible fixture. DEA has developed one that employs modular support and reference devices that are actually manipulated by the measuring robot. These fixtures are re-usable, thereby minimizing additional costs as new parts are introduced. What makes matters somewhat trickier is that the surfaces checked are often curved, not flat.