Investigation of machining characteristics and optimization of WEDM parameters for spark plasma sintered ZrB₂-B₄C ceramic composite utilizing RSM, NSGA II, and TOPSIS

Abstract A ZrB 2 -B 4 C (75 wt%–25 wt%) composite ceramic was fabricated using a Spark Plasma Sintering Furnace (SPS) at a temperature of 2000 °C. The electrical conductivity achieved was 1.5 × 10 5 S m −1 . The machining performance of the composite was evaluated using Wire Electrical Discharge Machining (WEDM) process. A central composite design (CCD) was employed to systematically examine the effects of key machining parameters, including pulse on-time (T on ), pulse off-time (T off ), pulse peak current (Ip), dielectric fluid pressure (WP), and servo feed (SF), on machining speed and kerf width. Regression models were developed to establish quantitative relationships between the input parameters and output responses, allowing for precise predictions of WEDM performance. The ANOVA results indicated that all the machining parameters significantly influenced machining speed and kerf width, with WP, SF, Ip, and T off notably affecting the machining speed, whereas Ip, T on , and SF impacted the kerf width. The micrograph of the machined surface revealed a white re-solidified layer containing numerous craters and protrusions. The machining parameters were optimized by the hybrid optimization technique, non-dominated sorting genetic algorithm (NSGA-II), and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), which identified the optimal parameter set as T on = 126 μs, T off = 60 μs, Ip = 130 A, WP = 9.00 kg cm −2 , and SF = 2075 mm/min for equal weightage (50%) of both responses.