A NONCONTACT AUTOMATIC-MEASUREMENT FOR FREE-FORM SURFACE PROFILES

This paper describes the process of developing a non-contact type auto matic measurement system for any free-form surfaces on a CNC coordinat e measuring machine (CMM) or a CNC machine tool, and its CAD/CAM integ ration, A laser probe, made by Keyence Co. model LC-2220, was integrat ed into the CNC machine as the non-contact sensor. Extensive calibrati on work has been carried out on the systematic accuracy of the laser p robe with respect to the color, material, surface slope, and edge dete ction of the workpiece through the use of a HP5528 laser interferomete r system. Measurement software has been developed for automatic surfac e tracing of any free-form profile. Having employed the surface painti ng technique, the shape error of the copied object relative to its mas ter piece was found to be within 30 mu m, which has been deemed adequa te for the mold industry. (C) 1998 Elsevier Science Ltd, All rights re served.