Laser Welding Thin Sheets for Car Body Structures
Published June 01, 1992 by ISATA - Dusseldorf Trade Fair in United Kingdom
Event: ISATA 1992
The analysis of interaction between the CO2 laser beam and the surface of zinc-coated and uncoated sheets has brought about the optimization of the shielding gas and its pressure at the point where the plasma develops, for maximum absorption of the laser beam and the most uniform weld bead possible. After performing various types of weld, in overlapping seams the optimum gap and the maximum admissible gap were determined to simulate real industrial tolerance conditions, and in these conditions fatigue strength was measured on testpieces. Welding without a gap and with partial penetration of the second sheet gives the best fatigue strength.
The overlapping zinc-coated sheets are correctly welded when the gap between them enables the zinc to escape. Experiments were then transferred to the automotive component, the intermediate car door pillar of the Renault partner vehicle. Rigidity and fatigue resistance were compared with that of traditionally spot-welded components and radical improvements were found.
Experience was acquired regarding the potential for laser applications in industrial production equipped with systems for beam handling and sheet clamping during welding.