Application of Taguchi method in the optimization of process parameters for conicity of holes in ultrasonic drilling of engineering ceramics

Abstract

This paper presents a study of the effect of process parameters on conicity of holes drilled by USM in alumina based ceramics using silicon carbide (SiC) abrasive. Conicity is defined as the difference between the hole diameters at the entry side and exit side per unit length of the hole produced. It is mainly due to lateral wear of the tool and use of harder tool materials. In order to achieve the objective of the present study, the experiments were conducted on an 'AP-500 model Sonic-Mill' ultrasonic machine.The parameters considered are workpiece material, tool material, grit size of the abrasive, power rating and slurry concentration. Taguchi's optimization approach is used to obtain the optimal parameters. The result shows that the conicity increases almost linearly as the grain size increases. The conicity also increases marginally with the increase in power and concentration. There is a significant interaction between tool & work piece, work piece & grit size and tool & grit size with regard to the raw data. The significant parameters are also identified and their effect on conicity is studied. The results obtained are validated by conducting the confirmation experiments.