Development Of High Efficiency Pulse Power Supply For Wire Cutting

W-EDM technology is one of the common methods in the field of material size processing at present,which is widely used in aerospace,military,automotive,semiconductor and other fields.Its core unit is the wire cutting pulse power supply,which plays a decisive role in the quality and efficiency of wire cutting processing.Machining efficiency of wire cutting refers to the removal rate of processed materials by pulse power supply in unit time.Machining efficiency is an important index to evaluate the performance of pulse power supply of wire cutting.In order to achieve high efficiency machining of wire cutting,this paper analyzed the influence of EDM machining mechanism and single pulse discharge energy on machining efficiency,combined with the current high-efficiency current slope power supply,A dynamic current slope discharge method is proposed.Based on the time-delay cascade loop,the resistance is cut into the main loop at different time intervals to realize the dynamic current slope machining.In order to realize current slope adjustment based on the gap state,a gap state detection method was designed.Different voltage thresholds were used to compare the gap state,and the output high level time of comparators corresponding to different processing states was calculated to realize the gap state detection.The feasibility of the above scheme was verified by simulation.Based on the traditional transistorized resistance pulse power supply topology,the main circuit design and system design of dynamic current slope pulse power supply are completed.The hardware part includes main controller MCU module,PWM power driver module,relay driver module,gap state detection module,high-frequency control module,communication circuit module and working power module.The software part includes initialization program,main program,interrupt service program,communication service program and upper computer communication and interface design program.The touch screen is used as the upper computer,the upper computer interface is built and the address and function code are allocated to the controls.The upper and lower communication is realized based on MODBUS protocol.The good interaction of the upper computer can realize the online modification of machining parameters and the function of gap state monitoring.Design the schematic diagram of the hardware circuit and draw the PCB,take anti-interference measures in hardware and software to complete the production of the pulse power prototype,perform the experimental test on the working performance of all levels of the circuit,and conduct the dynamic current slope scheme verification experiment,by setting different gap voltage values to simulate the gap state,perform the verification experiment on the performance of the gap detection circuit.