Online process control for laser beam materials processing

摘要

Laser beam materials processing requires both, high quality output as well as reliable monitoring actions for each processed part. The process diagnostic device commonly used in actual quality monitoring systems is a spatially integrating plasma sensor. Experimental results have shown that the reliability of the quality prediction can significantly be increased by using a camera system with a two-dimensional spatial resolution instead. Based upon these results an online process control system was developed. The system can be adapted for different applications like welding of tailored blanks or cutting. In the case of tailored blanks welding the system can monitor a full penetration of the workpiece, deviations from the desired welding path, seam width, stability of the capillary and defects of the seam caused by ejection of molten material. A closed loop control has been set up for monitoring of the penetration depth.