Researches Of RT-Linux Based EDM CNC System And Splinder Jump Control Technology

With the development of industry, hardworking materials with high strength and high hardness features are used, and bring lots of serious technological problems. And then, the advantages of no hardness restricted, high precision, and machining complex cavity structures in Electrical Discharge Machining (EDM) are significant, and is used widely in aerospace and die machining. For EDM machining, one of the most important technologies is the establishment of Numerical Control (NC) system. The performance of CNC system determines the result and efficiency of EDM machining to a certain degree, provides the favorable control functions for EDM machining, and is the guarantee for efficient and high precision complex cavity machining.According to the machining status, the structural framing was established and completed. RT-Linux was chose as the real-time platform. At first, the paper analyzed the hardware structure of EDM machine and the functions needed, and divided the functions in EDM software system, established the framework of CNC system. The structure of CNC system was built in accordance with the framework, and divisions between real-time tasks and non real-time tasks were made, the tasks'execute mode was finished also.The GUI of EDM CNC system was completed with QT software. Communication module in the system was analyzed. After the discussion of interpolation algorithm, the interpolation module, core module in CNC system, was programmed to realize interpolation function. The paper also analyzed and programmed two methods to realize jump function which could reach higher aspect ratio, and chose the better one be integrated in the CNC system.In order to optimize the jump control parameters, improve the discharge condition, enlarge the aspect ratio, the paper designed a fuzzy control system of jump process, which used short circuit rate and variation of short circuit rate as input and jump cycle as output. Also jump height was chose automatically to enhance jump effects.Finally, the CNC system was loaded in EDM machine to check its performance. EDM small holes experiment and EDM hexagram milling experiment were carried out. The experiment results showed that all modules worked well. The jump function was achieved, and the discharge conditions were improved obviously under fuzzy control system compared to those under no jump control or jump under regular time. The CNC system compiled could be used to control the EDM machining process.