Laser beam welding technology has been widely used to weld automobile components, especially for tailored blank welding. In order to provide best corrosion resistance to the welded sheet metal parts, zinc coated steel sheets are normally used. The zinc coating poses no issues to the butt joining of the sheet metals. However, when laser welding technology is applied to lap joint of these sheets, the welding process is not straightforward. Special techniques must be employed to allow the venting of the zinc vapor that is generated at the interface between the paired sheets. Many efforts have been attempted around the world trying to develop a practical technique for laser lap welding of zinc coated steel sheets. Most of the developed technologies has some success but with limitations-extra cost for equipment and process or limited convenience of implementation. In this paper, a new concept of laser lap welding with laser dimpling technology is described. This lap welding technique was implemented successfully in a robotic laser welding system in the laboratory environment and is capable of incorporation into manufacturing processes.
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