Optimization of the PM-EDM Process Parameters for Ti-35Nb-7Zr-5Ta Bio Alloy

Abstract

Powder-Mixed Electrical Discharge Machining (PM-EDM) is one of the latest advancements in EDM process capability augmentation. This procedure involves effectively mixing a suitable material in fine powder form with the dielectric fluid. The dielectric fluid's breakdown properties are enhanced by the additional powder. The objective of the present research is to machine the Ti-35Nb-7Zr-5Ta alloy prepared by powder metallurgy and study the influence of process parameters, such as peak current, pulse-on time, pulse-off time, powder type (Ag, Si, Ag+Si), and powder concentration. The metal removal rate and SR represent the response parameters. The Taguchi approach was followed to design the experiments. The five-factor three-level design was chosen to use the Taguchi L27 orthogonal array. It was found that the addition of Ag, Si, or Ag+Si powders to the dielectric fluid enhanced the metal removal rate and the surface finish for this alloy. The addition of Ag powder to the dielectric fluid gave a higher Material Removal Rate (MRR) and a lower SR compared to Si or Ag+Si powders. Powder concentration and pulse current are the most effective parameters on MRR and SR followed by powder type, pulse-on, and pulse-off. The maximum Grey Relational Grade (GRG) exists at (I=5 A, Ton=9 µs, Toff=37 µs, PT=Ag, PC=20 g/L). These are the optimal conditions for PM-EDM of the Ti-35Nb-7Zr-5Ta alloy that give maximum MRR with minimum SR.

Keywords

• TNZT alloy
• PM-EDM
• MRR
• SR
• GRA
• optimization