I am interested in using a Wire EDM process to cut some silicon steel. As defined by Wikipedia - “Electrical discharge machining (EDM), also known as spark machining, is a manufacturing process whereby a desired shape is obtained by using electrical discharges (sparks).Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage.”
Material suitable for EDM must be electrically conductive of the process to work. The steel I want to cut is laminated in a dielectric coating however. I contacted a few Wire EDM cutting companies and was told by some that it was not possible to Wire EDM cut a dielectrically coated material, and told by others - “maybe, it depends”.
What factors would this depend on? I am thinking that if the voltage used in the EDM process is above the dielectric breakdown point of the coating, then the process would work - is this a correct way to think about it? For example, this website (http://www.engineersedge.com/edm.shtml) states the peak voltage used ranges from 40 to 400V. This website (http://www.industrialcoatingservicesblog.com/coatings-dielectric-strength) lists the dielectric strength of some coatings as ranging from 800 volts/mil to 6000 volts/mil.
If the Wire EDM uses 400V, but the coating on the material has a dielectric strength of 800 volts/mil, is it a safe bet to say the coating is too strong an insulator, and that the EDM process will not work?
