“中走丝”线切割加工机床在使用1～2个月后加工工艺水平就开始下降,这与多次切割工艺的第一次切割采用高速走丝的切割方案有关.从参数优化策略的角度采用正交试验法对多次切割技术的第一次切割工艺参数进行了优化研究,分析了脉冲宽度、脉间/脉宽、峰值电流及走丝速度对加工效率和表面粗糙度的影响.试验结果表明,多次切割技术的第一次切割采用高速走丝方案并非最佳,采用中速或中低速走丝可能是更可行的方案.从优化的角度来看,多次切割工艺的第一次切割走丝速度由11m/s降到4.4m/s,加工效率降低约5％；而采用4.4m/s的走丝速度可使导轮及丝筒系统的运行速度下降60％,这对于降低导轮、轴承、导电块的机械磨损和电极丝的振动,提高机床的可持续精度是非常有利的.%Aiming at the problem which the processing performance of "medium-speed" WEDM starts to decrease after 1-2 months, it is relates to using the high-speed wire cutting scheme for the first cutting in multiple cutting technology. The first cutting parameter based on multiple cutting technology has been optimized by orthogonal test from the point of the parameter optimization strategies, and the effect of pulse width, the ratio of pulse interval to pulse width, peak current and travelling speed on processing efficiency and surface roughness has been analyzed. The experimental results show that high-speed wire cutting scheme for the first cutting on multiple cutting technology is not the best solution. Medium-speed or low-speed wire cutting scheme may be a feasible solution. From the view of optimization, if the speed of wire cutting scheme for the first cutting is decreased from 11 m/s to 4.4 m/s, the processing efficiency will be reduced by about 5 % , but the speed of the guide wheel and the wire tube system will be down 60 %. This will help to reduce the mechanical wear of guide wheel, bearings and conductive block, to reduce the vibration of the wire electrode, and to enhance sustainable precision of the machine.
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