Multi response optimization of CNC end milling of AISI H11 alloy steel for rough and finish machining using TGRA

Abstract

The AISI H11 tool steel is an essential material used in fabrication of tools & dies. It is an air hardening, high chromium, supreme carbon steel having high wear and abrasion resistant as the main features. Machining is a basic activity in production of tools & dies where the surface finish and metal removal rate play a very essential role. The purpose of the current study is to evaluate the influence of the machining parameters during milling upon the surface roughness (SR) and material removal rate (MRR) of AISI H11 steel. The machining tests have been performed on CNC vertical milling machine. Taguchi grey relational analysis (TGRA) with standard L27 orthogonal array (OA) has been selected to investigate the relationship between surface roughness (SR) and material removal rate (MRR). Optimization was performed considering each input parameter inside the range to obtain best combination of better SR and MRR. Analysis of data has been carried out in MS EXCEL software, and the model significance tests have been conducted using ANOVA method. The 20% weightage for response surface roughness and 80% for material removal rate is assumed for considering the rough machining conditions. The percentage contribution of cutting speed, feed rate and depth of cut for rough machining are 18.48%, 37.49% and 35.61% respectively. Whereas, 80% weightage for response surface roughness and 20% for material removal rate is assumed for considering the finish machining conditions. The percentage contribution of cutting speed, feed rate and depth of cut for finish machining are 71.55%, 13.88% and 1.09% respectively.