Digital Control Of Capacitance Charge-discharge Pulse In Electrospark Deposition Power Supply

Electric spark deposition is a kind of micro pulse arc welding process, makingconductive material melt and infiltrate into the metal substrate surface by using sparkdischarge. It can form alloying sediments which significantly improve the substrate’sproperty. ESD is increasingly widely used in modern industry. The traditional electricspark deposition power supply has a lot of shortages such as that discharge voltagecannot be continuously adjusted, discharge energy is unstable, SCR can not shut offstably, which limits electric spark deposition’s application range and decreases theefficiency of electric spark deposition. So developing a new and highly efficient electricspark deposition power supply is needed.This paper has analyzed the mechanism of electric spark deposition and theinfluence of power supply electrical parameters on the deposition efficiency and quality,a digital control of capacitance charge-discharge pulse in electro-spark deposition powersupply is developed, this power supply can independent control the capacitance’s chargeand discharge process. The overall scheme of the power supply, hardware circuit andsoftware system are designed. This power supply consists of CPU, rectifying andfiltering circuit, charge and its drive circuit, charge voltage comparator circuit, dischargeand its drive circuit, motorial electrode, etc. MOSFET and SCR series in charge anddischarge circuit respectively. Under the control of CPU and charge-discharge drivecircuit, MOSFET and SCR are turnon alternately. So with alternate charge anddischarge process of this power supply, even occurring a short circuit between theelectrode and the workpiece discharge can still normal. Charging voltage comparisoncircuit can realize stepless adjustment of discharge voltage.Hardware and software debugging test show that this power supply overcomes theshortage of traditional electric spark deposition power supply, and discharge voltage canachieve a step-less regulation. With alternate charge and discharge process, the SCR can be shut off safely even occurring short circuit between the electrode and the workpiece.And also discharge parameter adjustment is convenient. This power supply adapted tothe requirements of the various process conditions and improved the efficiency ofelectric spark deposition.