Pneumatic Spot Welding The Servo Gun Failure Mode And Countermeasures

At present, the traditional pneumatic spot welding gun has been unable to satisfy the requirements of automobile welding line with high-efficiency and high-quality, it will be gradually replaced by pneumatic servo spot welding gun. Due to the complex technology and high integration of pneumatic spot welding servo gun which incorporates with the automation production line as a whole, it is difficult to solve the fault when it occurres in the course of working. With the wide application of pneumatic spot welding gun in the automobile welding line, it is urgent that the thorough research of its failure mode and countermeasures should be conducted, and to provide fast troubleshooting techniques, methods and basis to the trouble-shooting is the guarantee which ensures the normal operation of the entire automobile production line. Aiming at this situation, the main work and achievements are as follows:1) The control principles and main function of the pneumatic servo spot welding gun are analyzed, and on this basis, the key technology simulation experiment platform is built, which can achieve main function of pneumatic spot welding servo gun, including position servo control, buffer control, force servo control and emergency stop, and provides a hardware foundation for the study of next failure analysis and strategy study.2) Potential failure modes are studied by the experiment of different fault points setting on the pneumatic servo spot welding gun simulation platform. At the same times, the impact of main components working status on system operation is analysed. In addition, based on the above experiment results, and combined with the actual welding fault in the process of the work, the comprehensive analysis of the each failure mode's causes is studied, and the impact of main failure modes is obtained.3) The fault tree theory (FTA) is used to analysis the main failure mode as a rapid trouble-shooting strategy. At the same time, fault tree minimal cut sets are determined based on the Fussell's top-down way. In addition, the quantitative analysis of the fault tree is studied by the method of Monte Carlo, and its procedures are complied by using the software of Matlab. At the last, the MTBF of system and the degree of importance of the working model in every main part are obtained.4) The trouble-shooting countermeasure about the pneumatic servo spot welding gun is studied, and the solution of main fault mode is proposed. In addition, in order to analyse the servo valve failure, and to test its quality performance, the electrical servo valve performance testing platform is designed, and the control procedures are complied by using the software of Labview. The platform can detect the servo valve's flow characteristics, pressure characteristics, and external leak detection. Through this platform, the performance of the proportional flow valve is detected, and the results show that the quality of the valve performance is consistent with its technical parameters.