关键词: 车身顶盖；侧围激光钎焊；密封胶；焊接效率；结构断面

Abstract: Given the problems of insufficient sealing, low efficiency and high cost in traditional spot welding for the roof of vehicle bodies, this paper takes a certain mid-sized sport utility vehicle (SUV) model as the object and compares and analyzes the process differences and comprehensive benefits of laser brazing and traditional spot welding between the roof and the side panels. The results show that laser brazing for the roof and side panels reduces the processes of sealant application and trim strip assembly, simplifies the process flow, and increases the welding efficiency by 52%. Laser brazing forms continuous and aesthetically pleasing weld seams, significantly improving the reliability of the body-in-white performance and the flatness of the appearance. In terms of economic benefits, laser brazing reduces the weight of each vehicle by 0.67 kg and lowers the direct material cost by 49 yuan. The research indicates that laser brazing outperforms traditional spot welding in terms of process simplicity, production efficiency, light weighting, cost control, and vehicle body performance, providing theoretical support and practical reference for the upgrading of vehicle body manufacturing processes.

Key words: roof of vehicle body; laser brazing of side panels; sealant; welding efficiency; structural section