Effects of Roughing Parameters in WEDM on Groove Width and Gap

Wire electrical discharge machining (wire-EDM) is very important in the manufacturing, due to its growing industrial and research applications. Inaccurate geometry in corner and especially sharp-curved corner cutting is one of the major problems in this process. Creation of exact geometry and high dimensional accuracy has been subject of many research works. In the present research, actual cutting slots on straight and curved paths are studied in roughing operation. Experiments are designed using the Full Factorial Method by considering frequency of discharges, wire tension and radius of curvature as variables. By employing statistical techniques in analysis, influences of these parameters on width of the cut of slot, on both straight and curved paths, are evaluated. Practical results for straight side gap and curved corner average gap are achieved, for each set of parameters. Because of concavity of wall on inner arc and convexity of wall on outer arc, measuring errors appear in the measurement of slot width at the curved corner. In addition, depletion of material and accumulation of material are observed at entrance and exit of the curved path, respectively. By calculating variable side gap on a curved corner, practical wire diversion and machining error are obtained.