In the present research, Ti-6Al-4V alloy was processed on wire-cut electrical discharge machine (WEDM) and the machining responses were analysed. The effect of machining variables was investigated on cutting speed (CS) and surface roughness (SR). Taguchi technique-based L 9 orthogonal array was considered for the planning of experiments. Grey relational theory is used for multi-characteristics optimisation. During the research, it was observed that the best optimal setting for the process parameters is A 1 B 2 C 2. At the suggested optimal setting, the predicted value of CS was 0.2044 mm/min and SR was 2.162 μm. These values are predicted at 95% confidence level. Scanning electron microscopy (SEM) investigates the surface morphology after the WEDM process. The surface integrity reveals the white-layer, sub-surface cracks and micro-cracks on the machined surface. The crack intensity increases with the increase of discharge energy.
Purpose
The purpose of this paper is to investigate the optimized setting of wire-cut electrical discharge machining (WEDM) parameters at which material removal rate (MRR) and mean roughness depth (Rz) set a compromise. The problem in the processing of Ti-6Al-4V by conventional processes is a high strength, high hardness, high tool wear. Due to which WEDM is adopted to machine Ti-6Al-4V biomedical alloy. Ti-6Al-4V alloy has a number of applications in the engineering and medical industries due to its high strength biocompatibility.
Design/methodology/approach
The effect of control factors (i.e. pulse on-time: Pon; pulse off-time: Poff; servo voltage: SV) on the MRR and Rz is investigated in the present research. The planning of experiments is done using a Taguchi-based L9 orthogonal array. The percentage influence of each factor on responses is also evaluated. The multi-objective optimization is done using the grey approach initially. After that, the results were also calculated using harmony search (HS). Therefore, a hybrid approach of grey and HS is used to find the optimized values of MRR and Rz.
Findings
The maximum value of grade calculated by grey-HS is 0.7879, while in the case of the experimental run the maximum value of grey grade is 0.7239. The optimized setting after improvisation at this grade value is Pon: 130 µs; Poff: 45 µs and SV: 70 V for MRR and Rz collectively. The validation of the suggested setting is completed by experimentation. The values of MRR and Rz are coming out to be 6.4 mm3/min and 13.84 µm, which represents improvised results after the implementation of the HS algorithm.
Originality/value
The integration of the grey approach with the HS principle in the manufacturing domain is yet to be explored. Therefore, in the present research hybrid approach of grey-HS is implemented in the manufacturing domain having applications in medical industries.
In the present research, Ti-6Al-4V alloy was processed on wire-cut electrical discharge machine (WEDM) and the machining responses were analysed. The effect of machining variables was investigated on cutting speed (CS) and surface roughness (SR). Taguchi technique-based L 9 orthogonal array was considered for the planning of experiments. Grey relational theory is used for multi-characteristics optimisation. During the research, it was observed that the best optimal setting for the process parameters is A 1 B 2 C 2. At the suggested optimal setting, the predicted value of CS was 0.2044 mm/min and SR was 2.162 μm. These values are predicted at 95% confidence level. Scanning electron microscopy (SEM) investigates the surface morphology after the WEDM process. The surface integrity reveals the white-layer, sub-surface cracks and micro-cracks on the machined surface. The crack intensity increases with the increase of discharge energy.
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