Welding in Automotive Body Assembly

For the past 40 years, welds in mass produced automotive body parts have been almost exclusively fabricated from pressed steel sheets and joined using resistance spot welding. The potential benefits of implementing laser welding technology are numerous - advantages may be gained in respect of single sided access, reduced flange widths, increased torsional stiffness (thus leading to improved vehicle structural performance and/or down gauging of material thickness), smaller heat affected zones and less thermal distortion, high speed automated processing and design flexibility (eg. in multi-layer joints).

Extensive work has been performed worldwide to realise the potential of laser welding for automotive body manufacture. As the turn of the century approaches, the number of systems installed in production is increasing, where two main types of laser welding are being employed. The first is a direct replacement for resistance spot welding or adhesive bonding, where lap joints or hem flange joints are utilised on pressed components for body-in-white assembly.

The second is the laser butt welding of flat sheets (which may be dissimilar thickness or material grade), which are subsequently formed into pressings. The pressings are called "tailored blanks" and the widespread acceptance of this technology has spawned a number of companies and enterprises associated with steel producers to meet the demands of the automotive industry in addition to in-house manufacture.