3D measurements of the knee prosthesis surfaces applied in optimizing of manufacturing process

Abstract The goal of this work is limited in the evolution of the superficial state in knee prosthesis. It is presented a 3D analysis in their topography, in order to optimize a manufacturing process. The material employed is alloy base cobalt. Its percentage minimum in weight is: 26.5% Cr, 4.5% Mo and the balance is cobalt. In attention to the complex form of the prosthesis, until now has been utilised a finishing technique manually. This system is very heavy, and besides it is not practice. Afterwards there is an additional problem in relation to the sickness that generates by the powder produced in the polishing action. For that, it has been thought in do this work with the mechano-chemical method to obtain a superficial finishing, as less similar so that it has been found until now. Since the medical point of view it is important than the surface roughness be small in attention to the contact of the prosthesis with the bone and with the polymer that it is founded in the back of the implant. The mechano-chemical method selected to make this work consists in a soft wear process in presence of an additive that helps to obtain the surface state wished. The pieces were obtained by the lost wax technique. We emphasize that the work consists in evaluate the roughness evolution in function of the mechanism proposed. We present different stages of this work until to obtain a surface state specular.