Product Code: ICAL09_904

On-Line Quality Control System for Laser Brazing
Authors:
Dmitri Donst, Fraunhofer I P T; Aachen Germany
Peter Abels, Fraunhofer I L T; Aachen Germany
Michael Ungers, -; -
Fritz Klocke, Fraunhofer I P T; Aachen Germany
Stefan Kaierle, -; -
Presented at ICALEO 2009

The laser brazing of steel with copper solder is widely established in industrial manufacturing. The reason are process advantages as a low working temperature and thus the low thermal distortion. In addition, the quality of the joint regarding surface appearance, joint strength and impermeability are fully ensured. The major obstacle for a wide industrial spreading of laser brazing is the high sensitivity of the process. Little disturbances of process variables such as an inaccurate wire feeder or misalignment of laser beam to seam cause imperfections such as pores, holes or one-side rather improper wetting. However, it is not possible to detect reliably those failures in the joint during laser brazing today. Therefore the goal is the development and qualification of a new quality control system for laser brazing. Therefore, in the first step the mechanisms of different joint imperfections were analyzed and evaluated. In the second step the joint failures that occur during the process were captured and analysed by using simultaneously two cameras. First camera use visible wave lengths and the second captures in the near infrared spectral region. For the space-resolved in-situ-detection of different process and quality characteristics both camera modules will be integrated coaxially into the laser processing head.