AN UNDERSTANDING OF THE EDM SURFACE INVOLVES THE TOPOGRAPHY, CHEMISTRY, AND METALLURGY OF THE SURFACE LAYER. THE MATERIAL PROPERTIES AND SERVICE CONDITIONS OF THE WORKPIECE MUST BE CONSIDERED. TO AVOID PREMATURE FAILURE, ALL OR PART OF THE EDM SURFACE LAYER MAY HAVE TO BE REMOVED. CHEMICAL OR ABRASIVE REMOVAL METHODS MAY BE USED. SURFACE LAYER MODIFICATION MAY ALSO BE DONE BY HEAT TREATMENT.
