Metal Additive Manufacturing for Load‑Bearing Implants

Abstract

Additive manufacturing (AM) has seen a remarkable evolu‑
tion during the last three decades. AM gained attention due to its ability
to manufacture complex structures in a single operation without partspecifc tooling. Initially used for rapid prototyping, researchers realized
the potential of AM to create functional parts. Technological advances
in additive manufacturing techniques and machines have been a con‑
tinuous process since attempting to use AM in almost every manufac‑
turing sector with a wide range of materials. One of the primary sectors
embracing AM technologies is the biomedical industry for processing
metallic load-bearing implants. Conventionally manufactured implants
are available in a fxed range of sizes, resulting in potentially improper
bone remodeling since each patient’s anatomy is different. AM offers
the freedom to manufacture patient-specifc implants by mimicking the
patient bone to replace an implant. At the same time, designed porosity
can be introduced in the generic metal implants, which enhance tissue
integration and reduce the elastic modulus of the implant, preventing
stress shielding. Selective laser melting, electron beam melting, and
directed energy deposition-based AM techniques are commonly used
for fabricating metal implants. Metals such as titanium (Ti) alloys, cobaltchromium (Co–Cr) alloys, and stainless steel (SS) are popular choices for load-bearing implant applications due to their excellent mechani‑
cal strength, no cytotoxicity, and good corrosion resistance. Research‑
ers have been developing Ti, Co–Cr, and SS-based metallic alloys using
additive manufacturing techniques for the past two decades. This article
is focused on AM processed load-bearing metallic implants.