One of the major problems with this process is error of cutting in corner radii. In this research, investigations have been made on this subject and solutions have been proposed and experienced. Practical works were implemented on tool steel 1.2510. As proposed by the Charmilles(the machine manufacturer) one roughing and two finishing operations were considered for cutting. To start the experiments, primarily, the influence of discharge frequency, inter–electrode gap voltage, and feed-speed were experimented for two finishing operations. In the next step, the effects of frequency of discharges and feed speed were investigated for roughing operation. In finishing operations, experimental design and analysis was based on Response Surface Method and the Full Factorial Method was employed for the roughing work.There results showed that, optimization of these parameters have a better influence for control of residual material thickness on straight paths rather than curved corners. However, optimization of these parameters, in this stage, could reduce the corner radii errors about 25 percent.It was also discovered that, the roughing operation is the most influencing part of cutting. Based on this conclusion, a second course of experiments were designed on the Full Factorial Method basis for roughing operation by considering frequency of discharges, wire tension and radius of curvature as variables and the residual material and the width of cut of slot on straight and curved paths as the output parameters. Experiments showed that the thickness of residual materials left on the workpiece on straight and curved paths had less than one-micron difference and these simply can be corrected by an appropriate offset. KeyWords: Wire Electro–Discharge Machining, corner radii, residual material, wire deflection, wire inclination, wire diversion, groove width
