The measurement-aided welding cell—giving sight to the blind

Abstract

This article introduces the concept of a measurement-aided welding cell (MAWC). It then focuses on developing the MAWC for body and chassis components in the automotive industry. Industry 4.0 requires flexibility and reconfigurability from manufacturing systems, which has been addressed by cellular manufacturing systems (CMS). Traditional automotive welding technology is not flexible enough to be used as a CMS. So, the core of automotive production does not meet the needs of next-generation manufacturing and Industry 4.0. For the first time, this demand has been answered—by the MAWC. The MAWC is based on two handling robots, a welding robot and an optical measurement system, all integrated into one welding cell. The measurement system controls guides and gives feedback to the handling and welding robots. This way, accurate welding is based on actual part-to-part adjustment, rather than hard mechanical tooling. The lack of hard mechanical tooling allows flexibility. Measurement-assisted assembly and machining is not new. However, it has not previously been applied to complex welding processes, because traditional measurement technologies have not been satisfactory. A newly developed system using multi-camera measurement technology meets the flexibility requirements. The technology required for a MAWC is reviewed and found to be in common use in the automotive industry. Three development projects are presented in which the main functions of a MAWC are successfully demonstrated. Two of these projects were done with BMW. A MAWC allows the manufacturing process to immediately swap to a different product on the same line, increasing the production line utilisation rate and making it possible to produce several low-volume products in one manufacturing system. So, the MAWC will not only yield benefits from its scalable capacity and global decentralization, but it will also open new business opportunities for manufacturing low-volume luxury car parts or post-production spare parts.