... electrical spark erosion carving, When we use hard alloy and queched mold steel for mold, we must use ... spark eletrode, copper eletrode will be consumed fastly, and veracity can not be promised. But if we use ... be reduced greatly, erosion speed will increased obviously, and veracity will be shift to much higher level. To ... Contacts, Vacuum Contacts, Electrodes for Resistant Welding and Spark Erosion.