Parametric optimization of wire EDM process for single crystal pure tungsten based magneto-caloric material using taguchi grey relational analysis

Magneto caloric material is best suitable for regulating the heat flow at cryogenic temperature of below 10 K. There are different magneto caloric materials such as Beryllium, Gallium, Cadmium and Tungsten that function as heat switch at below 10 K cryogenic temperature. Among these, Tungsten is preferable because of its high Debye temperature and low critical superconducting temperature. Thus, in this study, single crystal pure Tungsten is chosen as magneto-caloric material. For converting Tungsten crystal to required shape and size as per desired application, machining is important. Several traditional techniques are available for machining the single pure Tungsten material but wire Electrical Discharge Machining (EDM) is preferable for high hardness, resilience, and corrosive resistance features. Therefore, in the present work, wire EDM process is considered for machining the single crystal pure Tungsten. Before machining of any material, parametric optimization is conducted for reducing the operating cost, material wastage, number of experiments and time. In this study parametric optimization of wire EDM process for Tungsten material is conducted using Taguchi grey analysis method. In this method, seven input parameters such as pulse on time (0.0003ms-0.0005ms), pulse off time (0.012ms-0.016ms), arc off time (0.012ms-0.016ms), water pressure (10.7bar-15bar), wire feed (8.4g/min-10.6g/min), wire tension (1473.33gf-1767.60gf) and gap voltage (42V-46V) and three output parameters such as material removal rate(0.2mm/min-0.4mm/min), kerf width (0.330mm-0.355mm) and surface roughness value (0.0012mm-0.0021mm) are chosen for parametric optimization. From the parametric optimization analysis, it is found that maximum material removal rate, minimum surface roughness, and better kerf width is preferable. (author)