对EDM表面的理解涉及表面层的形貌、化学和冶金。必须考虑工件的材料特性和使用条件。为避免过早失效，可能必须去除全部或部分EDM表面层。可以使用化学或磨料去除方法。表面层改性也可以通过热处理完成。

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.