An effective-wire-radius compensation scheme for enhancing the precision of wire-cut electrical discharge machines

Abstract

Using a modified Denavit–Hartenberg (D–H notation), we propose with this study a methodology for generating the wire-radius-compensated NC data equations required to carry out the machining of non-column workpieces on a five-axis wire-cut electrical discharge machine (WEDM). In the proposed approach, the designed surfaces of the machined component are constructed using a 4 × 4 homogeneous transformation matrix and ruled surfaces. The modified D–H notation is then employed to derive the machine’s ability matrix and to generate the desired wire location matrices. To ensure the precision of the machining operation, the wire location matrices are modulated by a novel effective-wire-radius compensation scheme. Finally, the NC data equations required to machine the component are derived by equating the ability matrix with the modulated wire location matrix. To validate the proposed methodology, three non-column workpieces with various top and bottom basic curves are machined on a commercial WEDM. The dimensions of the machined components are then compared with those of specimens machined using the built-in WEDM compensation scheme. The results show that the components manufactured using the proposed effective-wire-radius compensation scheme are more geometrically precise than those produced using the conventional WEDM compensation method.