预孔深窄槽变姿态加工方法研究

Research on Variable Attitude EDM Machining Method of Pre-hole Deep Narrow Slots

深窄槽结构通常用于涡轮叶片封严槽和轮胎模具钢片槽。电火花加工深窄槽时会因放电产物排出困难而存在耗时长的问题,故提出一种预孔深窄槽加工方法,通过将电火花打孔和电火花成形加工工艺相结合来改善排屑条件、提高深窄槽加工效率,并对预孔窄槽的变姿态加工进行了研究,先对预孔数量和间隙宽度控制策略进行优化,再在此基础上分别研究了竖直向下、水平和倒置三种加工姿态对预孔深窄槽加工效率的影响,并通过间隙状态分析和间隙流场观测对不同加工姿态的影响进行了解释。结果表明:加工姿态为竖直向下时,预孔深窄槽的加工效率最高,加工用时比无预孔时缩短了35.6%。

Deep narrow slot(DNS)structures are commonly used in slots for seal slots in turbine blades and inserts in tire molds.Due to the difficulty in evacuating discharge products,electrical discharge machining(EDM)of DNSs becomes a time-consuming process.To improve the machining efficiency of EDMing DNSs,a pre-hole EDM machining method which combines the EDM drilling and EDM machining is proposed.The number of pre-hole holes and the control strategy of the gap width is optimized.On this basis,the influence of machining attitudes,including the downward,the horizontal and the inverted,on the machining efficiency of pre-hole DNSs is studied.Among them,the downward machining attitude shows the highest machining efficiency,whose machining time is reduced by 35.6%compared with that without pre-hole.In addition,the gap states analysis and the gap flow field observation are used to explain the effects of machining attitudes on the machining efficiency.