When it comes to mechanical processing, the surface condition of the workpiece material is of utmost importance. If the cutting parameters are not set correctly, the surface may be damaged due to excessive heat, internal stress, or other factors, and this can negatively impact the overall polishing effect. In particular, the surface layer after EDM is much harder to grind compared to surfaces produced by other machining or heat treatment methods. It is therefore advisable to finish EDM before the end of the process, else the surface can be left with a hardened thin layer that is difficult to work with.