Application potential of combined fuzzy-TOPSIS approach in minimization of surface roughness, cutting force and tool wear during machining of CP-Ti grade II

Abstract

Titanium and its alloys possess numerous inherent qualities such as high corrosion resistance, temperature resistance, bio-compatibility and high strength-to-weight ratio. These alloys are extensively used in widespread areas viz. spacecraft, aerospace, marine, medical, oil and gas, chemical processing industries, etc. around the globe. In spite of the aforesaid popularity, machining of titanium alloys is very costly and difficult due to their poor thermal conductivity and high chemical affinity. Low thermal conductivity causes rapid tool wear owing to excessive machining zone temperature. Tool failure at its pre-mature stage considerably curtails the surface quality of the end product. This situation necessitates an appropriate set of machining variables so that one can achieve high productivity without compromising the quality. Keeping these facts in mind, the present paper proposes fuzzy coupled with TOPSIS method to identify an optimal combination of process variables during turning of commercially pure titanium. Spindle speed, feed and depth of cut were selected as three input parameters, whereas surface roughness (Ra), cutting force (Fc) and flank wear (VBc) were the major responses. Experiments were performed according to Taguchi’s L27 orthogonal array. Analysis of variance (ANOVA) test was performed to identify the most significant machining parameter and to verify the potential application of the proposed methodology. The results indicated that the fuzzy-TOPSIS method is capable of deal with both qualitative and quantitative criteria to reach at the best parametric combination during turning operation.