The Effect of The Machining Process UHMWPE on The Wear Behaviour of Acetabular Cups for Hip Implants

Abstract

Ultra High Molecular Weight Polyethylene (UHMWPE) has been consumed in human hip implants for the last decades. Improving the reliability of hip joint implants can reach by the understanding of wear behavior and morphology of the polyethylene. The purpose of this investigation was to determine the effect of the manufacturing process UHMWPE on the wear behavior of acetabular cups for hip implants. Tribological tests of UHMWPE acetabular liner on AISI 316L stainless steel femoral head were carried out with a tribometer test configuration in a dry condition. In this study, wear testing was examined with constant applied load of 800 N. The superficial injures that occured during the test were assessed by coordinate measuring machine (CMM) and roughness measurements. A correlation between the surface roughness from machining process and wear mass loss was assessed and discussed. Based on the results of the test data and observations on the specimens it can be concluded that the machining UHMWPE acetabular cups using milling CNC significantly affected the UHMWPE surface roughness developing its wear act, in terms of, the rate of wear depth and wear coefficient produced. The results show high linearity.