Analyzing wire deflection errors of WEDM process on small arced corners

Abstract

Wire electrical discharge machining (WEDM) is an advanced machining process capable of precise machining of parts with complicated shapes. Machining inaccuracy at small arced corners is a major problem of WEDM process. It is aimed to develop a novel mathematical methodology validated by experimental data for analyzing the wire deflection and evaluating total machining errors of arced corners during the WEDM process. The maximum spark gap, spark angle around the wire, spark forces applied to the wire and the resulting deflection are mathematically described based on the nature of the electrical discharge process and plasma channel properties to clarify the causes of wire deflection error in the small arced corners. The influence of the driving WEDM parameters, including discharge frequency and wire tension, are theoretically and experimentally studied in regard to the wire deflection and total machining errors for various experimental sets. Finally, the estimated wire deflection and total machining errors are compared and evaluated. The results indicate that wire deflection error is one of the major causes of machining errors in the arced corners; this error is almost 57% of the total machining error. In addition, the effect of wire vibration and excitation of discharges on the total machining errors are mentioned. According to the results, it is concluded that the proposed theoretical formulations can be used for prediction and compensation of wire deflection errors in the arced corner machining.