微细电火花混粉加工微孔初探

Exploratory Study of Micro-hole Drilling by Micro-EDM in Powder-mixed Dielectric

微孔在工业中应用广泛,根据其材料、精度、尺寸不同,有各种加工方式。微细电火花加工能加工任何导电材料、不受工件材料的强度和硬度限制,因而广泛应用于航天航空、医疗、机械行业。但微细电火花深孔加工排屑困难,造成加工效率降低。提出一种微细电火花微孔加工方法,可将工作液中混入一定浓度的金刚石粉末,通过管电极将工作液送入加工区域,旨在改善深孔排屑问题。结果表明:相较于未添加粉末的情况,添加粒径5μm的金刚石粉末时,出入口直径差减小34%、加工效率提高27.21%;添加粒径10μm的金刚石粉末时,电极损耗长度减少76.7%。

Micro -hole is widely used in industry. There are various micro drilling processesavailable for different size of hole, material and accuracy. One of them is micro electrical dischargemachining （EDM）,which has the ability of processing any electrically conductive materials regardless oftheir strength and hardness. However,it is a challenge to drill deep micro hole by micro EDM due tothe difficulty of debris and bubbles removal in working area. In this paper,the powder-mixed dielectricis used in drilling micro hole by micro EDM. The powder-mixed dielectric is supplied to the workingarea via tube electrode. Experiment results show that the diameter difference between the entrance andthe exit has been reduced by 34% and the machining efficiency has been improved by 27.21% whenthe powder size of5 μm is used. Electrode wear has been reduced by 76.7% when diamond size of 10μm is added into dielectric.