Analyzing the Surface Finish of Knee Implants to Determine Criteria for Applications in Direct Metal Laser Sintering

Abstract

Direct metal laser sintering (DMLS) is a relatively new additive manufacturing technology that has the potential to decrease processing time and allow for more customization. For this reason, DMLS would be useful for applications in the field of knee prosthesis. However, before DMLS components may be placed in the body, many requirements must be met for the implant to be considered safe and have long functionality in the body. One important aspect is surface roughness, which helps determine how well the components will osseointegrate with the bones in the body. The focus of this research was to determine the surface requirements of an established knee implant, which will be used as the criteria that DMLS must achieve for applications in this field. To determine the surface roughness values: Ra, Rq, and Rz, a profilometer was used on components of the knee implant and a DMLS tensile bar to make a comparison. The results showed that the DMLS part did not meet the roughest and smoothest surface requirements that were shown in the implant. According to this research, DMLS is not ready for applications in this field. However, the results in this research will allow DMLS to know the parameters needed to achieve this goal in future. Further investigations could be to test DMLS biocompatible materials and to see the effect of changing machine parameters on surface finish.