Slanted and cluttered: Solving deficiencies in SLM-manufactured lattice geometries

The rapid growth of the geriatric population in industrial societies is expected to increase the demand for prosthetic implants. Unfortunately, current products exhibit shortcomings such as inadequate sizing or excessive material strength both of which hamper the recovery of fractures. Selective laser melting (SLM), as a manufacturing method, is highly suited for optimizing the geometry and topology of products. However, SLM however, seems to restrict the manufacturing precision to mostly horizontal printing which is inefficient when considering the build envelope. Additionally, certain elongated geometries are subject to warpage when printed horizontally. To address these issues, our study investigated the feasibility of vertically oriented porous structures using SLM. It will report on two specific deficiencies, namely slanting and cluttering, that were revealed through X-ray computer tomography. To facilitate the manufacturing of slender, porous structures, the paper will offer and examine heuristics that minimize the defects. The preliminary results indicate that structures such as shell reinforcements and bio-inspired unit cells reduce the occurrence of slanting and cluttering and might serve as interim solutions for the printing of large filigree structures. The general findings suggest that more dedicated research is necessary to understand the relationship between geometrical features and manufacturing precision in SLM.