Research Of Precision Micro-arc Spot Welding Power Supply

In the manufacture of microelectronic devices, medical devices, sensors, etc, a lot ofprecision welding processes are involved. As a precision welding technology, Micro-arc spotwelding has the features such as beautiful welding forming, welding joints are solid andreliable, small heat influence area, etc., and it has incomparable advantage over other weldingespecially in special materials and small coil end fusion. Welding current, welding time andcurrent waveform has a very important impact on the quality of micro-arc spot welding.Therefore, the paper starts from the impact elements of micro-arc spot welding. Design anddevelop power supply that can better adapt to the micro-arc spot welding process and satisfythe demands of precision welding.The paper discusses the design schemes of power supply, and the digital high-frequencyinverter power supply is designed, which is based on DSP. Choose full-bridge inverter as thetopological structure of main circuit, key components of this circuit is designed and selected.The control system based on the single chip dsPIC33FJ64GS610was designed, including ahigh-frequency driving circuit, feedback sampling circuit, switching value input and outputinterface circuits, LCD and keys circuit, etc. It has completed the main circuit and controlcircuit PCB design according to the design requirements. Software for the power system isalso designed. The programs of PWM, A/D sampling, PI control, arc control, LCD and key,etc. are written and debugged.The experiment platform was built, and it has completed installing and debugging thepower supply of micro-arc spot welding. The power system achieves automatic control ofWelding sequence, closed-loop stable output and has a protection link. Through Micro-arcspot welding process analysis, five processes are designed including strike arc, slow rise, themain welding, slow down and closing arc. By precise control of welding process current andtime, the welding current resolution up to0.1A and the welding time accuracy of up to0.1mscan be realized. Set the parameters for the process to get a flexible welding current waveform,so that the power system is suitable for different welding occasions. The tiny lines of differentdiameters are chose to do some micro-arc spot welding experiments. The results show that high-quality welding products are obtained through micro-arc spot welding. The tiny line endconnector has sleek apperance, and it has a combination of solidity and reliability, basiclysatisfied the requirements of precision welding. Consequently the system is worthwhile torecommend.