ABSTRACT
Tool steel is the important material to produce the mold and die for industries such as forging die for automotive part industry. SKD 61 is tool steel that recommended using for hot working. High hardness and withstands wear are important properties and also has a relatively high resistance to shock. In order to use for die, this material must be machined by turning or milling operation and hardened by heat treatment process. In order to make molds and die, Wire Electrode Discharged Machining (WEDM) has been most operations. In order to obtain better material removal rate, the suitable setting of WEDM parameters is important before the process takes place [1]. So, there are several factors affected to productivity, such as Power setting, Off time off, Wire feeding, Wire tension and Wire offset. These factors of WEDM could be affected to product based on the machining parameters. Furthermore, there are several researches to study the factors affected to the process of WEDM. Tarng et al. [2] applied a neural network system to determine settings parameter for the estimation of cutting speed and surface finish. Kosit and Jirapattarasilp [3] used a Taguchi’s methods to determine factors for surface roughness of WEDM on SKD 61 steel. Mohammadi et al. [4] investigated roundness improvement in wire electrical discharge turning. Scott et al. [5] studied a factorial design method to determine the optimal combination of
control parameters in WEDM. Lok and Lee [6] compared the performance of WEDM in terms of material removed rate and surface finish through observations obtained by processing of two advanced ceramics under different cutting conditions.
