Optimization of machining parameters influencing machinability of Al2124SiCp (45%wt) metal matrix composite

Abstract

Taguchi method is used to find the optimal cutting parameters for turning Al2124/SiCp (45%wt) metal matrix composite using polycrystalline cubic boron nitride (PcBN) and polycrystalline diamond (PCD) tools. Experiments were performed with High Precision Lathe Machine Model No: CG6125C. The parameters selected were cutting speed, feed, depth of cut, and tools. The output responses considered for the investigation were surface roughness, tool wear, and specific power consumption. Results show that the optimal combination of parameters giving the best surface finish are at cutting speed of 60 m/min, feed rate of 0.2 mm/rev, depth of cut of 0.10 mm, and PCD tool. The analysis also show that the optimal combination of parameters is at cutting speed of 40 m/min, feed rate of 0.15 mm/rev, depth of cut of 0.20 mm, and PCD tool insert give the lowest specific power. Dominant wear mechanism observed is abrasion wear affecting flank face. Uncoated PcBN had greatest wear followed by coated PcBN and finally PCD tool. Tool insert has a dominant effect on surface roughness having a contribution of 82.04% and followed by cutting speed having a contribution of 4.51%. On specific power consumption tool insert has a dominant effect having a contribution of 65.14% and followed by feed rate with a contribution of 13.57% and interaction ( ap ×  f) with a contribution of 9.92%. It is observed that optimization of the two characteristics for machinability of Al2124SiCp (45%wt) metal matrix composite simultaneously is difficult. On tool wear the results showed that PcBN tools suffered severe wear as compared to PCD tools.