| The number of our country’s automotive output and sales has been number one in the world for many years, and automotive is becoming more and more common for ordinary families. Recliner being acted as the main bearing component of the automotive seat, it connects seat bracket and base. Recliner not only provides the passengers comfortable driving experience, but also the welding quality is directly related to the passengers’ safety.At present, the parts of automotive seat recliner are mainly designed by the spatial structure. The plate become thin but with a higher strength of welding, and the shape of welding beams are various with a discrete distribution. Now widely used in gas shielded welding, resistance welding, and even common laser welding can’t completely meet the requirement of the processing. Based on the market, and on the principles of green and environment protection, safe and reliable, precision and fast, this paper developed the research on galvanometer scanning laser welding system and welding process. All of the research are as follows:The theory of galvanometer scanning laser deep penetration welding has been studied. The composition and working principle of scanning galvanometer are introduced, and the mechanism of laser deep penetration welding is analyzed. The process of laser deep penetration welding has been studied, including the influence of plasma behavior and main process parameters such as welding power, welding speed, spot size and focus position on deep penetration welding.The galvanometer scanning laser welding system of automotive seat recliner has been designed. Based on the welding requirements, the welding safety house has been designed and the system components are determined. A reasonable design proposal has been made after researching the characteristics and the principles of key cells such as disk laser, PFO, welding robot, 4D-WeldWatcher. The PLC logic control programs have been designed, including the digital and analog value of I/O system design, welding seams programming and man-machine interface optimization.The galvanometer scanning laser welding process of automotive recliner has been studied. Taking reinforcing plate as the typical example with the analysis of the recliner’s structure and using single factor transformation method to find out the most reliable welding parameters for the seam surface and strength. The results showed, when the laser power is 8000 W, scanning speed is 72mm/s and the defocus is 15 mm, we can get a better result of welding beam appearance and strength, while getting maximization of economic benefit. On this basis, the further welding process about ramp-up pulse shape and cool-down pulse shape has been studied. The results showed, when the ramp-up power is 3200 W or 4800 W, and the distance is 4mm, welding reinforcement and welding crack can be decreased by ramp-up pulse shape at the beginning. When the cool-down power is 3200 W or 4800 W, and the distance is 4mm or 6mm, concavity and crack can be reduced by cool-down pulse shape at the end. |
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