随动导丝及喷水机构大锥度高速电火花线切割研究

Study on HSWEDM Possessing Function of Guiding Wire and Following-up Spray during Large Taper Cutting

高速往复走丝电火花线切割机床大锥度(≥±5°)切割时,受到诸多因素的影响,尤其是电极丝采用导轮定位产生的结构误差的影响,加上切割时工作液不能很好地包裹住电极丝并随着电极丝沿倾斜方向进入加工区域,使其加工精度和表面粗糙度比直体切割时差很多,对于锥度零件的多次切割特别是大锥度零件的多次切割则显得更加困难,其根本原因是没有能够保持电极丝空间位置及稳定性的随动导丝器和喷水机构。为此,设计了一种随着电极丝倾斜能随动导丝并跟踪喷液的六连杆大锥度随动导丝及喷水机构。通过试验,在相同加工参数条件下,新型随动机构与现有机构相比,圆锥加工误差从80μm减小到40μm,表面粗糙度Ra从4.059μm减小至3.495μm,多次切割后加工精度可以达到25μm(锥度±20°,工件厚40mm),表面粗糙度Ra达到1.670μm。

Because many factors especially the structure error influences caused by wire electrode using wheel positioning,and dielectric fluid cannot grip the wire electrode very well so that could not flow into the machining area with wire electrode along the direction of dip when big taper parts in cut-ting,the machining accuracy and surface roughness of the taper parts were worse than parts with stretched cutting.Multi cutting of taper parts especially big taper parts was much more difficult.The basic reason was that it had no follow-up guide and spray mechanism which could keep the wire elec-trode space position and stability.In view of the above mentioned problems,the paper presented the design of a six connecting rod big taper follow-up guide and spray mechanism that could guide wire along with wire electrode’s inclination and realize tracking spray at the same time.On the basis of new mechanism,experimental results show that taper machining errors decrease from 80μm to 40μm. Surface roughness Ra decreases from 4.059 μm to 3.495 μm.After multi cutting,taper machining （taper±20°,thickness 40 mm）errors are decreased to 25 μm.Surface roughness Ra is decreased to 1.670 μm.