Customized implants with specific properties, made by selective laser melting

The purpose of this paper was to present how customized implants could be made with specific properties, by setting different values of the laser power, within the selective laser melting (SLM) process. A detailed case study was undertaken and a new multi-structured femoral prosthesis was designed and analyzed, to simulate its behavior for a specific case study.

The materials and manufacturing methods are presented, with details regarding the SLM process, using the Realizer 250 machine. The laser power was varied between 50 and 200 W, thus obtaining samples with different physical and mechanical characteristics. All those sample parts were characterized and their properties were measured.

A practical methodology was found to produce multi-structured implants by SLM. Significant changes of the porosity and properties were found, when modifying the laser power at the SLM machine. The studies have indicated an open porosity varying between 24.810.83 per cent. Tensile tests of the samples showed Young’s modulus values varying between 13.5 and 104.5 GPa and an ultimate stress between 20.2 and 497.5 MPa.

There is no Additive Manufacturing (AM) machine available, to work with different laser power values, in different regions of the same section of the implant. Hence, a multi-structured implant cannot be obtained directly.

The prosthesis should be specifically designed to contain separate models/regions to be made with appropriate laser power values.

This paper presents a new method to design and manufacture a multi-structured implant, using the existing AM equipment. A detailed case study is presented, showing the design procedure, the way to simulate its behavior and the methods to produce the implants by SLM.