High power Nd:YAG laser welding of automotive materials

摘要

The automotive industry is the largest production user of high power continuous wave (CW) Nd: YAG lasers primarily in the field of thin section body-in-white welding. Because of Nd: YAG laser wavelength (1.O6μm), this allows fibre optic beam delivery, which means the laser can be easily integrated in the production line as a substitute for conventional welding processes, e.g. resistance spot welding. Laser welded floorpans; pillar/roof assemblies, doors, bonnets and boots can now be found in many automobiles. The advantages include a reduction in weight from the use of narrow flange widths, increased stiffness associated with continuous welds, a reduction in scrap from the use of pressed tailored blanks, and increase in flexibility in the design and manufacturing. With the additional driving force of weight reduction, laser welding of aluminium alloys has become a pertinent subject to the automotive industry. This paper describes the welding trials carried out on zinc coated steels and aluminium alloys with high CW Nd: YAG lasers capable of delivering up to 4kW at the workpiece. Different welding techniques were explored to overcome problems associated with zinc coated steels in terms of porosity, and aluminium alloys with cracking and porosity respectively.