Model-based pyrometer alignment method for additive manufacturing by laser metal deposition

Abstract

The melt pool temperature is a key parameter in laser metal deposition (LMD) processes. Reliable temperature measurements are of obvious interest and essential for supervising and controlling the process. However, pyrometers tend to show a non-negligible directional dependency, due to the direction-dependent temperature distribution in the melt pool. We propose a model-based method for determining and physically compensating the misalignment of a pyrometer in an LMD process. The approach is based on a brief calibration run based on which the focus offset can be determined. The resulting offset is used to physically adjust the pyrometer.