微細線切割在模具隅角加工精度之探討

The Working Accuracy of Mold Corner Cutting by Micro-WEDM

本研究使用微細線切割放電加工機進行隅角加工精度之研究，所採用之加工液為去離子水，線電極為30μm微細鎢線，材料則為熱處理後厚度(t)6mm之SUS420不銹鋼，對應相對的放電參數厚度(T)6mm，其機台內顯示的智慧型加工參數為:噴流壓力(P)為1.2bar、線張力(FW)為0.8N、線走速(AW)為75mm/s。本研究主要討論調整線張力(FW):0.5、0.8、1.1、1.5(N)時各種隅角加工之加工精度，在加工道次上為六道次，分別加工30、60、90度的V-cut溝槽，來探討幾何外形之加工精度。研究結果顯示，線張力(FW)的調整對幾何外形尺寸的影響是最顯著的，在線張力最小0.5N與最大1.5N的調整時，最大約有17μm的差異，以加工參數的調整加工30、60、90度V-cut溝槽時，線張力以不斷線之最大線張力1.5N為佳。

In this study, the Micro Wire Electrical Discharge Machining (Micro-WEDM) machine was used to research the corner cutting accuracy. The dielectric was de-ionized (DI) water, the diameter of wolfram wire selected was 30μm. The material was Stainless Steel SUS420 after heat treatment. The discharging parameter thickness and the workpiece thickness were the same as 6mm. From the input conditions, the smart program in the machine automatically chose working parameters with flushing pressure (P) of 1.2 (bar), wire tension (FW) of 0.8 (N), and wire speed (AW) of 75 (mm/s). The wire tension (FW) working parameters was adjusted to is 0.5、0.8、1.1、1.5 (N), processing six times with 30、60、90 degree V-cut grooves to observe the corner cutting shape. The results revealed that the variation of the corner cutting shape is mainly affected by wire tension. The corner cutting shape was changed about 17μm when the wire tension chosen was between 0.5N (minimum) and 1.5N (maximum). Based on the results from cutting 30、60、90 degree mold grooves, the optimal wire tension applied should be 1.5N better.