Experimental studies of ultrasonic machining on hydroxyapatite bio-ceramics

Abstract

Hydroxyapatite bio-ceramics are used for producing implants for bio-medical applications. The generation of hemispherical shaped cavity on hydroxyapatite bio-ceramic is highly demanded for making hip joint. Ultrasonic machining is suitable for the machining of all kind of hard and fragile materials, which are electrically non-conducting. This paper is aimed to design and develop a tool and holding arrangement in ultrasonic machining (USM) for generating hemispherical shaped cavity on hydroxyapatite bio-ceramic which is highly demanded for hip joint replacement. This paper also includes the study of the influences of process parameters such as abrasive grain diameter, abrasive slurry concentration, tool feed rate and power rating on material removal rate, diametrical deviation, and circularity error during ultrasonic machining. From the basic parametric studies, it is observed that the abrasive grain diameter, power rating, and tool feed rate are the most important parameters, which have greater influence on the material removal rate (MRR), diametrical deviation, and circularity error of hemispherical cavity on hydraxyapatite bio-ceramics. It is also concluded that the hemispherical shaped cavity on hydroxyapatite bio-ceramics with dimensional accuracy can be generated by USM with the aid of developed tool geometry and proper control of process parameters during ultrasonic machining.