Study On Prolonging The Replacement Period Of Spot Welding Electrodes

Resistance spot welding has become one of the key connection technologies in modern refrigerator compressor manufacturing industry.It has many advantages,such as heat concentration,short single welding cycle time,no need to fill metal,good welding environment and automatic welding.The resistance spot welding electrodes are mainly responsible for conducting current,exerting pressure,driving heat dissipation and so on.In the actual high temperature and high pressure production process,combined with the harsh environment of continuous spot welding,the speed of electrode wear failure is accelerated.Although the electrode can be grinded and reused,the electrode grinding not only brings labor costs,but also increases production costs.Frequent replacement of the electrode can not only reduce production efficiency,but also affect the stability of product welding quality.At present,the research on improving electrode life mainly focuses on the improvement of electrode material and structure.Few refrigeratory compressor manufacturing industries extend electrode life by optimizing welding parameters.Based on the exploratory thinking of lean production,this paper starts from the fundamental point of eliminating waste and improving production efficiency to reduce production costs,and then focuses on the Six Sigma project of GY company's shell accessories welding line to reduce the cost of electrode use.Aiming at the current cost of resistance spot welding electrode,the process elements analysis,FMEA and Pareto diagram are used to analyze the current production process of resistance spot welding.The main factors affecting the service life of electrode(i.e.the electrode replacement cycle discussed in this paper)are welding current,welding pressure and welding time.Then,the influence of three welding parameters on the electrode replacement cycle is deeply studied.Firstly,the orthogonal experimental design method is applied to select three factors(welding current,welding pressure and welding time)to design resistance spot welding of 3.0 mm shell sealing terminal assemblies.The sub-three-level orthogonal test,based on the measurement system of the standard for evaluating the appearance of the welded surface of the shell sealed terminal,shows that the response indexes of different experimental groups are different electrodereplacement cycles.The orthogonal experimental results were analyzed by range analysis and variance analysis,and the order of influence degree of different welding parameters on electrode replacement cycle was obtained.The optimum welding parameters were obtained by orthogonal test: welding current 55 KA,welding time 215 MS and welding pressure 0.35 MPa.The experiment response electrode replacement cycle can be optimized from 1000 sets per time to 2000 sets per time.The optimized welding process parameters combination and the response electrode replacement cycle are applied to actual production.The cost of using the electrode is obviously reduced,and the production efficiency is also greatly improved.The research methods and conclusions of this subject are verified.The validity of the theory.The work in this paper is of great significance to the study of the service life of electrodes in refrigerator compressor manufacturing industry.