Synergic Control Research Of Arc Pulse Energy Parameters In Pulse MIG Welding

Because of its unique pulse current, Pulse MIG welding has the excellence ofless spatter, all position welding, achieving automatic control easily, nice weld jointand high welding quality, and has become a highly efficient, high quality weldingmethod. When the welding current is less than spray-transfer critical current, PulsedMIG welding can achieve stable spray-transfer droplet and can weld varied metalthicknesses, it is widely used especially in the field of aluminum alloy material. As thePulse MIG welding automation degree is higher and higher, for adjustment problemsof numerous pulsing parameters, this paper comes up with synergic control method,optimizes pulsing parameters of arc energy, realize stable effect of one pulse with onedroplet, and increase stability of arc, to improve further welding process performance.New process put forward higher requirements for welding equipment, in order tomeet the requirements of higher welding quality. Pulse MIG welding inverter powercontrol system is designed in this paper, based on the digital signal controllerdsPIC30F6010.The main circuit consists of full-bridge inverter with IGBT, theinverter power make use of PWM module inside of DSP chip to give four unattachedpulses which drives IGBT to close. With duty cycle of inverter adjusted, the dynamiccharacteristics of the inverter power will be changed. In chapter of hardware circuit, itdescribes design of inverter switch driving circuit, protection circuit and feedercontrol circuit in detail. In part of software, Welding main program, peak/baseprogram, PI control program and initialization program, etc, are compiled inmodularization programming.Based on the analysis of pulse MIG welding droplet transition behavior, thispaper brought forward waveform of pulse current with dual slope, to enhance dropletcontrollability. The system achieves current and arc length closed loop control bysoftware. The current loop controls current wave fine, that gets the one droplet perpulse. The voltage loop controls arc length, get steady arc and improve the arc lengthconsistency.The results of the experiment show that the pulse MIG inverter with well controlability of droplet transfer realizes one droplet per pulse and has the high arc lengthconsistency based on the dsPIC30F6010chip.