Alexandria Engineering Journal (Dec 2020)
Multi-objective optimization in titanium powder mixed electrical discharge machining process parameters for die steels
Abstract
In this paper, it has been proposed a viable optimal solution for achieving multi-objective optimization in powder mixed electrical discharge machining (PMEDM) process parameters, using titanium powder. Taguchi–AHP–Deng’s method is used to solve the multi-criteria decision making (MCDM) problem for this technology. The process parameters selected are workpiece material, electrode material, electrode polarity, pulse on time (Ton), pulse off time (Tof), current (I), and powder concentration. The material removal rate (MRR), tool wear rate (TWR), surface roughness (SR), hardness surface (HV), and white layer thickness (WLT) were determined simultaneously. The results showed that the optimal material for the workpiece is SKD11 die steel; the optimal material for the electrode is Gr; and the polarity of the electrode should be positive. The optimal values for the other process parameters were determined to be Ton = 20 μs, Tof = 57 μs, and I = 8 A, and that for the powder concentration was 10 g/l. The quality criteria for the optimal process parameters were determined to be MRR = 59.669 mm3/min, TWR = 14.073 mm3/min, SR = 4.45 μm, HV = 907.64 HV and WLT = 8.56 μm. The results were verified through experiments, which revealed a good accuracy (error ≈ 11.67%). The white-layer formation on the machined surface was reduced using titanium powder-based PMEDM for die steel at the optimal conditions. The results showed that Deng’s similarity method is the most suitable for MCDM in PMEDM using titanium powder.
