Analysis of tool attitude error for a steep taper wire-cut electrical discharge machines using multibody approach

The tool attitude error of steep taper wire-cut electrical discharge machines (EDM) is a significant factor affecting the taper angle error of the workpiece. This study investigated a wire EDM machine that can handle 15 degrees taper through the control of U and V axes. A mathematical model of attitude error is established in the coordinate system of machine tools based on the multi-body approach, considering the coupling relation of parts controlling the movement of the wire. It is found that the positioning error is the major factor contributing to the attitude error by studying the effect of each error component of the U and V axes. Furthermore, the positioning errors of the U-axis and V-axis are close to zero from the very beginning during a 100-mm journey and reach maximum values of 30 mu m and 28 mu m at 100 mm as the moving distance increases. A comparison experiment is conducted for improving the positioning accuracy of the U and V axes. The results show that the decrease in the positioning error can effectively reduce the volumetric attitude error; attitude error was reduced by 36% in the experiment. Therefore, the mathematical model on tool attitude error is validated.

Automated summary

This study investigates the effect of tool attitude error on the taper angle error of steep taper wire-cut electrical discharge machines (EDM) and establishes a mathematical model. The research finds that positioning error is the major factor contributing to the attitude error. A comparison experiment shows that reducing positioning error effectively decreases the volumetric attitude error.