FEEDBACK CONTROL OF PROCESSING TEMPERATURE IN LASER BEAM HARDENING OF PRODUCTION DIES

摘要

Automotive draw and line dies are often subjectrnto high wear and tear in the areas with convexrnradii during volume production and require heatrntreatment to improve the mechanical propertiesrnin these areas in order to increase the operatingrnlife of the die. Laser beam transformationrnhardening has been proven to be a viablerntechnology for such type of heat treatment. It hasrnbeen demonstrated that laser hardening processrnprovides better overall hardness and morernconsistent levels of quality compared tornconventional heat treatment processes.rnExperimental results show that the processingrntemperature during laser beam hardening is onernof main key factors in achieving the highestrnhardness on the die surface. At Magna, a laserrnprocessing system has been integrated forrnimplementation of laser beam hardening of dies,rnwhich includes expanded beam spot, precisernprocessing temperature control, as well as offlinernprogramming and automatic tool pathrngeneration. This paper describes the practice ofrnlaser hardening dies, including influence on thernprocess of different types of material, analysis ofrnlaser hardened materials, the effect of therngeometry of processing area on the processingrntemperature and the requirement for temperaturerncontrol in process.