Design of Metallic Lattices for Bone Implants by Additive Manufacturing

A broad range of synthetic trabecular-like metallic lattices is 3D printed in Ti-6Al-4V by SLM. The aim is to propose new conceptual types of implant structures for superior biomechanical matching and osseo-integration: synthetic bone. Systematic evaluation is then carried out: (i) their accuracy is characterised using HR X-ray tomography, to assess deviations from the original geometrical design intent and (ii) the mechanical properties-stiffness and strength-are experimentally measured and compared. Finally, this new knowledge is synthesised in a conceptual framework in the form of implant design maps, to define the processing conditions of bone tailored substitutes. The design criteria emphasise (a) the bone stiffness matching, (b) preferred range of pore structure for bone ingrowth, (c) manufacturability, and (d) choice of inherent materials properties for durable implants. The power of this framework is demonstrated in the design of a prototype spine fusion device.