A study on the machining-parameters optimization of wire electrical discharge machining

Abstract

A suitable selection of machining parameters for the wire electrical discharge machining (WEDM) process relies heavily on the operators' technologies and experience because of their numerous and diverse range. Machining-parameters tables provided by the machine-tool builder can not meet the operators' requirements, since for an arbitrary desired roughness of the machining surface, they do not provide the optimal machining conditions. An approach to determine parameters setting is proposed. Based on the Taguchi quality design method and the analysis of variance, the significant factors affecting the machining performance such as metal removal rate, gap width, surface roughness, sparking frequency, average gap voltage and normal ratio (ratio of normal sparks to total sparks) are determined. By means of regression analysis, mathematical models relating the machining performance and various machining parameters are established. Based on the mathematical models developed, an objective function under the multi-constraint conditions is formulated. The optimization problem is solved by the feasible direction method, and the optimal machining parameters are obtained. Experimental results demonstrate that the machining models are appropriate and the derived machining parameters satisfy the real requirements in practice.