The hole of which the diameter is 2 mm, the depth/diameter ratio is more than 20 and the taper is less than 0.5% can be machined successfully on the general sink EDM machine tool by using the tube column electrode or the tube flatted electrode.

• 分别用管状圆柱电极和削边电极在通用电火花成形加工机床上成功地加工出直径为2mm、深径比大于20、锥度小于0.；5%25的深小孔。