Modeling and reducing workpiece corner error due to wire deflection in WEDM rough corner-cutting

Abstract

Workpiece accuracy is one of the key technology indexes in wire electrical discharge machining (WEDM), and workpiece corner error is an important form of workpiece geometric error. The goal of this paper is to model and reduce workpiece corner error due to wire deflection in WEDM rough corner-cutting using a novel surface microstructures wire electrode (SMWE) and cut-back method. Firstly, based on string vibration theory, a wire deflection model is presented to reveal the forming mechanism of workpiece corner error during rough corner-cutting, and the theoretical solution of corner error due to wire deflection is derived out. Secondly, a set of single factor experiment is implemented to analyze the improvement effect of SMWE on the corner error. Experiment data indicates that the proposed SMWE can decrease workpiece corner error by 5.53–27.15% comparing with brass wire electrode (BWE) in rough corner-cutting. Besides, the influences of process parameters on corner error are also investigated. Additionally, through the inverse method, the discharge resultant force acting on wire electrode is acquired, and the calculated data of corner error shows good agreement with experiment data in verified experiment. Finally, on the basis of wire deflection model, the cut-back method (CBM) is proposed to compensate wire electrode path, and it is proved that this method can reduce workpiece corner error by about 87% in rough corner-cutting.