فهرست مطالب حمید آبیار فیروزآبادی

Wire Electrical Discharge Machining (WEDM) is known as an advanced manufacturing process, especially for producing delicate and intricate shapes and cutting difficult-to-cut materials. Machining error on is an important problem associated with this process. The current paper investigates experimentally the machining errors of three-stage WEDM on the small straight and arced paths. To reveal the reason behind these errors and to compensate them, residual materials of each cutting stage on the straight and arced corner paths were separately measured and analyzed. Machining errors of each WEDM stage in both paths were accurately considered and the causes of these errors in the straight and small arced paths were experimentally and theoretically determined and discussed. Experiments showed that the roughing stage has such a serious deteriorating influence the machining errors on the arced paths that it cannot be compensated in the following finishing stages. The spark angle domains of the roughing stage on the arced paths were calculated and the effects of these domains on the machining errors due to wire diversion from the programmed path were analyzed. In addition, this research proposes a novel guide in multi-stage WEDM by defining some machining concepts and developing equations for error calculation of WEDM finishing stages on these paths. The machining errors estimated by equations have consistency with the related experimental ones. of this study can be employed in the accurate WEDM cuttings.

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.

Wire electrical discharge machining (wire-EDM) is able to generate delicate and complex shapes on hard materials which are difficult to cut. Inaccuracy in the cutting of small radius curved corners is one of the major problems in this process. In the present paper, corner radii machining errors have been investigated. Experiments are designed using the Full Factorial Method for roughing operations by considering frequency of discharges, wire tension and radius of curvature as variables, and the residual material on straight and curved paths as the output parameters. Practical works are implemented on tool steel 1.2510. By employing statistical techniques for analysis and by calculating variable side gap on curved corners, the machining error is obtained for 150, 300 and 450 µm radius curvatures. Results show that the thickness of residual material left on the workpiece on straight and curved paths can be the same if the cutting path on curvature is corrected according to the findings of this paper.

Lack of machining accuracy، at corners and corner radii، is one of the major problems in Wire-EDM process. The focus of investigation in this work was on corner radii errors through successive cuts of roughing and finishing operations. Effects of discharge frequency، inter-electrode average gap voltage، and feed-speed were investigated for finishing operations. Residual material left on straight path and over-cut on convex curved path were measured. Results indicated that the influence of the input variable parameters on the thickness of the residual material on straight paths is remarkable in comparison to curved corners. Ultimately، for corner radii، an optimum set of parameters could reduce the errors only by 12%. It was، then، concluded that the roughing operation is the most influential stage of cutting on corner radii