Novel Methods for Online High-Accuracy Quality Control of Laser Welded Blanks and Tubes

摘要

The quality of a laser butt weld used for laser welded blank and tube applications is influenced by many parameters and is critical to be kept under control in an industrial production environment. Additionally, the quality specifications continuously increase. New applications like hydroforming of laser welded tube and tailored blank as body-in-white parts are challenging regarding weld quality. Seam imperfections like concavities, non-fused zones, skips or pores are not acceptable due to the formability requirements and the corresponding enormous seam elongation. We have developed a quality control system based on a novel high-speed image-processing platform. With fast software algorithms we are able to accurately reproduce the edge and seam profiles of a laser butt weld. The profiles are measured and calculated with a precision of the order of a few microns. The high accuracy is attained by applying modern CMOS cameras with logarithmic response. Field test results show the unique performance of the system integrated in a tailored blank and tube welding machine.