Simulation-based Control of Laser Hardening of Steel

The goal of the laser surface hardening is to achieve a constant hardening depth and at the same time to avoid surface melting. To this end one can use the measured temperature in the hot spot of the laser on the workpiece for controlling the laser power. However, in case of workpieces with varying thickness or with cavities close to the surface a constant surface temperature usually does not lead to a constant hardening depth. In this paper we propose a new method which uses numerical simulations to compute a non constant surface temperature leading to a constant hardening depth. The latter can be used as a set point temperature for the machine based process control.