High speed spark erosion drilling machine 1.The speed of drilling hole is 30mm-60mm depth per minute 2.Z axis with fixing func High speed spark ... on the various conductive materials,especially stainless steel,chilled steel,copper,aluminium and hard alloy etc.3.Z axis with fixing ... -3mm(thedepth-diameter ratio is 300:1)5.Can dill wire-cut starting hole,filter hole,jet hole,gas hole,group ...