Experimental investigation of the influence of wire offset and composition on complex profile WEDM of Ti6Al4V using trim-pass strategy

Wire electric discharge machining (WEDM) is an important non-traditional manufacturing technique for industries processing hard-to-machine materials. It can produce complex shapes with high dimensional accuracy and surface finish. Ti6Al4V is frequently used in biomedical applications such as surgical implants, dentistry, and orthopedic wires. All these applications require machining complex profiles with high accuracy in terms of dimensions and surface properties. Multi-pass machining is a proven technique for minimizing the damage on the machined surface but increasing the number of passes lowers the productivity. Hence, careful selection of wire offset value for trim cutting is crucial to maintain process efficiency and keep the number of passes minimum. The objective of this study is to investigate the effect of wire offset in multi-pass machining on surface integrity, dimensional accuracy, and cutting speed in complex WEDM of Ti6Al4V and limit the number of trim passes to one. In addition, effect of electrode composition on machining responses is studied for three different types of wires (uncoated brass, Broncocut-W, and Topas Plus X). Experimental results indicate that a single trim cut at an offset value of 0.11mmprovides better surface finish and minimum recast layer. Surface roughness of 1.31 mu m is obtained using brass wire: 16.5% and 18.6% less than for Broncocut-W and Topas plus X, respectively. Similarly, recast layer of 8.183 mu m attained by brass wire is smaller than 8.98 mu m, and 10.041 mu m produced by the other wires. The uncoated brass wire has proved to be the best electrode for surface finish, recast layer thickness, and dimensional accuracy of the machined profile. However, Bronococut-W wire has performed better in terms of cutting speed.