Experimental Investigations into Nano-finishing of Freeform Surfaces Using Negative Replica of the Knee Joint

Abstract

To achieve high level of surface finish is a difficult task especially in complex shaped components, 3-D components and components with freeform (or sculptured) surfaces. Knee joint is one of such components which has freeform surfaces. Surface finish is very expensive and time consuming operation. Moreover, surface finish of a knee joint plays a crucial role in its functionality and life expectancy. The range of variation of surface roughness value on the different faces is required to be minimum. With these objectives in view, Rotational - magnetorheological abrasive flow finishing (R-MRAFF) process is being proposed with special tooling to achieve the above said objectives.To have uniform (or minimum variation) surface roughness values on all the four faces, a negative replica of the knee joint has been fabricated as a fixture so that the medium flow velocity is approximately constant throughout the length of the joint. Secondly, pulsating magnetic field is used to create vibrations in the abrasive particles so that the probability of new abrasive particles interacting with the knee joint surface, is high.