Research On Change Causes And Uniform Control Of Wire Tension In HSWEDM

The wire tension change problem, especially the non-even wire tension, has always been a challenge since high-speed WEDM(HSWEDM) was invented. That is, the wire tension is usually tight at the motor end and loose at the handwheel end after the wire electrode running a certain period. This problem will affect the machining accuracy and cutting stability, and also increase wire wear and the probability of wire breaking.Therefore, this paper made a systematic research about the wire tension change problem in high-speed WEDM. And the main works of this paper are as follows:(1) Based on the MCU and the LabVIEW software, this paper designed a test system which can monitor the tension and speed of wire electrode. And the collected data can provide an important basis for cause analysis of wire tension change.(2) The wire tension change problem in high-speed WEDM has been studied with the test system. Asymmetric structure design of wire-winding mechanism is considered as the main cause of this problem. According to the analysis results, a conductive guide wheel and a adjustive wire-winding mechanism have been designed preliminarily.(3) Based on the cause analysis, a mathematical model of wire tension change has been built and a corresponding simulation system has been developed. And simulation results are basically consistent with practical condition. The effect of each parameter on wire tension have been analyzed with the simulation system which provided a theoretical basis for the wire tension control.(4) The wire-winding mechanism has been redesigned according to the cause analysis and simulation results. The experimental results suggest that the non-even wire tension can be effectively controlled in the redesigned mechanism. And the redesigned wire-winding mechanism can improve cutting stability and efficiency in large thickness cutting processes as well as the consistency of workpiece dimension in multi-cutting processes.