cr12mov线切割电参数优化及变质层分析word格式论文.docxVIP

ABSTRACTWire electric discharge machining which has been developing from the 1960’s has been widely applied in the modern industry, especially in mould processing field. Quality of the mould processing is one of the main influence factors for the die life. Thus the mechanism of WEDM should be studied to guarantee the die life. It’s complicated and changeable, having many influence factors, so the objective law is difficult to control. According to this situation, we have done some work about the affected layer and the influence law of the electric parameters on the technical index.First, taking the view that mould processing is one critical influence factor on die life as the entry point, operational conditions and characteristics of machine tools are understood through onsite inspection in the mould enterprise. On the base of reading lots of literature about mechanisms of WEDM, we are familiar with the current research status in this field.Second, through analyzing and summarizing the literature information, and based on the study, confirm the main electric parameters affect the processing effect need to be controlled: current peak, pulse width, pulse intervals and servo voltage. Design an orthogonal experiment including four factors that each one has three levels, considering four processing index: processing speed, surface roughness, dimensional accuracy and white layer thickness. The result of the extreme difference and variance analysis shows the influence law of all the electric parameters on each processing index, the order of importance of each factor and the optimized electric parameters combination. The comprehensive balance method is used to choose a best parameters combination comprehensively considering the four processing index.Finally, due to the affected layer produced in WEDM has an important influence on the die life, we observe the micro morphology and microstructure, and measure residual stresses on the surface. The difference between WEDM and ot