Optimization of Selective Laser Melting process for zirconium lattices as orthopaedic implants

Selective Laser Melting (SLM), with its ability to fabricate lattice structures, represents a promising solution for the fabrication of orthopaedic implants. However, achieving high quality lattices poses a challenge with the need to optimise the process parameters for the specific designed structure. Here, laser power, scanning speed, and hatch spacing were varied at three levels to optimise the SLM process for zirconium (Zr702) for bone substitution. Measurement of the impact of these process parameters was undertaken using X-rays computed tomography (XCT) and confocal microscopy. XCT was used to evaluate the manufactured lattice in terms of geometrical deviation from the designed structure, macro-structural integrity, and internal defects while the latter technique was used for surface finish measurement. The optimal levels of laser power, scanning speed and hatch spacing identified in this study enable the fabrication of Zr702 lattices with adequate geometric compliance, strut connectivity, interconnected architectural porosity and low levels of internal defects.