Design Of Energy-saving Micro-EDM Pulse Generator Based On FPGA

Micro EDM has the characteristics of non-contact,no burr,low stress,etc.It occupies an important position in the field of micro machining.It is an irreplaceable technology in the processing of micro size parts such as micro holes,micro grooves and micro three-dimensional structures.The pulse generator provides the energy for eroding materials for micro EDM,which is a key factor in determining the machining performance of the machine tool.With the increasing demand for micro devices and the trend of miniaturization of mechanical manufacturing,pulse generator has gradually become the main factor restricting the development of micro EDM technology.This paper starts with two aspects of micro-EDM pulse generator and its gap discharge status detection technology.First,based on the discharge processing principle of the controllable RC pulse generator,the design requirements of the micro-EDM pulse generator are summarized,and the flyback pulse generator is designed.The generator uses a single-ended flyback circuit as the main topology.The flyback converter can be used to regulate the multilevel energy output of the pulse generator.In addition,the secondary side of the flyback converter has a controllable dual energy storage capacitor circuit to achieve multiple Energy level processing and cleaning pulse function.Among them,multi-energy level machining can control the discharge energy of the micro-EDM machining process to improve the gap discharge status and stabilize the entire machining process;and the cleaning pulse function can solve the problem of chip removal in micro-machining and help improve machining efficiency.The highspeed gap detection circuit can sample the gap voltage and current data in real time,and provide real-time gap data for the discharge status detection module.The pulse generator uses FPGA as the main control chip to realize the generation of PWM drive signals and complete the CAN bus communication with the micro machine controller.In order to realize the accurate detection of the discharge status,the discharge status detection technology based on machine learning is studied.Collect and filter gap voltage and current data through FPGA,and extract several voltage and current values as the characteristic points of a single discharge pulse.The waveform characteristics of the discharge gap were analyzed,and the classification standard of the training samples was established.The offline training of the pulse classifier was implemented using the Python programming language.Finally,the model was implemented on the FPGA to complete the online recognition of the pulse classifier.The flyback pulse generator designed in this paper is used to perform related experiments on micro-EDM machines.The experiments show that the pulse generator can perform efficient and stable work with good reliability;the discharge status detection module can realize the identification of a single discharge pulse,and statistics The proportion of harmful pulses in a period of time can predict whether the gap discharge status is degraded;multi-energy-level pulses can improve the discharge power of the pulse generator,which is conducive to processing efficiency;cleaning pulses can further improve processing efficiency,but at the same time affect electrode loss and processing accuracy.