Nanofinishing of freeform surfaces of prosthetic knee joint implant

Abstract

The freeform complex surfaces have become an inevitable part of many components to perform specific functions. Many of these components require nanometer surface roughness to meet specific requirements in their application domain. Therefore, finishing operation as a final operation is necessary for such components. A magnetorheological fluid-based finishing tool is developed for finishing knee joint implant, which has complex freeform surfaces. Different types of magnetorheological fluids and various finishing steps are proposed to reduce finishing time. Surface characteristics of the knee joint implant are studied using a surface roughness measuring instrument and atomic force microscopy before and after finishing. A significant reduction in surface roughness (the best final surface roughness value obtained = 28 nm) is observed on the component after finishing. The surface roughness obtained on different surfaces is well within the values recommended in the ASTM standard for total knee joint prosthesis.