Research On The Power Supply And Welding Arc-process Behavior Of Magnetically Controlled Micro TIG Spot Weldin

Sheet metal is an integral part of high-tech products such as electronics,automobiles,aerospace and medical equipment.Argon arc welding has great advantages in the welding of sheet metal.However,the arc stiffness is poor in low current welding,and the arc stability is poor and the application reliability is low.In order to solve this problem,the thesis plans to use the magnetic-controlled arc to improve the motion characteristics of the arc and improve the stability effect of the arc during operation.The following researches are made around this method:Based on the inverter technology,the main circuit topology of arc welding power supply is designed,and the components in the main circuit are selected according to the energy transmission path.The control mode of micro TIG spot welding power supply is programmed with the control chip to realize the control of various output modes of power supply.Double inverter technology is used to design the excitation power supply,so that it can output AC and DC current at the same time.In addition,the excitation coil which can generate longitudinal magnetic field and transverse magnetic field is designed for specific welding gun.The motion behaviors of micro TIG arc under the action of DC longitudinal magnetic field,AC longitudinal magnetic field and AC transverse magnetic field were photographed by high-speed camera respectively.The arc motion law and arc compression behavior were analyzed by combining with image processing technology.The results show that the arc stability and stiffness under the action of AC transverse magnetic field are the best.A 304 stainless steel sheet with a thickness of 0.2mm was used as the test material.The magnetic(transverse AC)micro-Ti G welding test was carried out under the same welding parameters and compared with the micro-TIG welding test.The results show that the former has better suppression effect on the surface cracks of solder joints and multi-solder joints,and the welding joint has better consistency.Then,the effect of welding process parameters on the welding quality of thin slices was studied by response surface analysis,and the optimal welding parameters were obtained.Compared with the micro-Ti G welding,the tensile shear force of the joint welded by micro-Ti G spot welding was larger,the consistency of welding quality was better,and the grain structure was finer.This method provides the basis for wafer welding of arc welding.