铜镍合金微金字塔阵列模具线切割加工工艺研究

Wire Cutting Process for Micro-Pyramid Array Die of Copper-Nickel Alloy

目的应用慢走丝线切割加工工艺,加工C71500铜镍合金的微金字塔阵列结构,获得高精度玻璃模压用模具。方法采用单因素工艺实验法研究脉冲宽度、脉冲间隔、走丝速度对加工表面质量及尺寸精度的影响。应用超景深三维显微镜、激光共聚焦显微镜以及电子显微镜对线切割后的微金字塔阵列模具尖点表面粗糙度和圆弧半径进行检测,并对微金字塔阵列模具尖点圆弧半径不均一性现象进行研究,通过综合优化得到最优工艺参数。结果加工后尖点表面粗糙度随脉冲宽度的降低而减小,随脉冲间隙的增大呈先减小后增大的趋势,随走丝速度的增大而减小。尖点圆弧半径随脉冲宽度的降低而减小,随脉冲间隙及走丝速度的增大而减小。经过综合优化,当脉冲宽度为6μs、脉冲间隔为14μs、走丝速度为6m/s时,微金字塔阵列模具尖点获得最低的表面粗糙度(Ra=9nm)和最小的尖点圆弧半径(5.41μm)。相比优化前,表面粗糙度降低60.9%,尖点圆弧半径减小53.0%。加工时电极丝与工件电极接触面积的变化,是导致慢走丝线切割后微金字塔阵列尖点圆弧半径不均一现象的主要原因。结论利用慢走丝线切割加工方法,可以在铜镍合金模具材料上加工出尖点圆弧半径均一的微金字塔阵列结构,同时可获得微米级尺寸精度和纳米级表面粗糙度。研究结果为慢走丝线切割加工铜镍合金微金字塔阵列结构提供了一定的参考。

The work aims to obtain high-precision glass molding die by processing C71500 micro-pyramid array of copper-nickel alloy with Low Speed Wire Cut Electrical Discharge Machining (LS-WEDM) technology.Single-factor process experiments were carried out to study the effects of pulse width,pulse interval and wire speed on surface quality and dimensional accuracy.Super-depth 3D microscope,laser-scanning confocal microscope and scanning electron microscope were used to measure and analyze the surface roughness and arc radius of the micro-pyramid array die after cutting.Besides,the heterogeneity of cusp radius of the micro-pyramid array die was studied,and the optimal process parameters were obtained by comprehensive optimization.The surface roughness of the processed cusp decreased with the decline of the pulse width,firstly decreased and then increased with the increment of the pulse interval,and decreased with the increment of the wire speed.The arc radius of the cusp decreased with the decline of the pulse width,and decreased with the increment of the pulse interval and the wire speed.After comprehensive optimization,micro-pyramid array die cusp could get the optimal surface roughness (Ra=9 nm) and the minimum cusp radius (5.41 μm) when the pulse width was 6 μs,the pulse interval was 14 μs and the wire speed was 6 m/s.Compared with the experimental results before optimization,the surface roughness was reduced by 60.9%,and the cusp radius was reduced by 53.0%.The change of contact area between electrode wire and workpiece electrode was the main reason for the heterogeneity of cusp radius of micro-pyramid array after LS-WEDM.A micro-pyramid array die with uniform cusp radius,micron-scale dimensional accuracy and nano-scale surface roughness can be fabricated on the copper-nickel alloy material by LS-WEDM.This research work is instructive and meaningful to micro-pyramid array die of copper-nickel alloy by LS-WEDM.