In January 2019, Tong Hi-Tech undertook the project of FAW Hongqi's welding plant at the Changchun base, and was responsible for the "turnkey project" of the four-door laser flight welding workstation for C229&E115 models. At present, in the process of body development, in order to enhance the visibility of the body, it is necessary to design the narrow frame of the window. This means that the width of the flange side of the window frame is narrow, and the traditional spot welding process cannot meet the manufacturing requirements. At present, there are three main manufacturing processes to solve the narrow frame of the body: small spot welding, Aplas welding and laser welding. Comparison of advantages and disadvantages of several processes: