A non-contact automatic measurement for free-form surface profiles

This paper describes the process of developing a non-contact type automatic measurement system for any free-form surfaces on a CNC coordinate measuring machine (CMM) or a CNC machine tool, and its CAD/CAM integration, A laser probe, made by Keyence Co. model LC-2220, was integrated into the CNC machine as the non-contact sensor. Extensive calibration work has been carried out on the systematic accuracy of the laser probe with respect to the color, material, surface slope, and edge detection of the workpiece through the use of a HP5528 laser interferometer system. Measurement software has been developed for automatic surface tracing of any free-form profile. Having employed the surface painting technique, the shape error of the copied object relative to its master piece was found to be within 30 mu m, which has been deemed adequate for the mold industry. (C) 1998 Elsevier Science Ltd, All rights reserved.