02 Nitinol Additive Manufacturing Review

Additive manufacturing (AM) has significantly expanded the design and application of NiTi (Nitinol) alloys in medical devices by enabling the fabrication of complex geometries, fine features, and patient-specific structures that are difficult or impossible to achieve through conventional methods. This review provides a focused and comparative overview of AM technologies applied to NiTi in biomedical devices. This review presents the AM technologies relevant to NiTi, including powder bed fusion (PBF), directed energy deposition (DED), Sheet Lamination (SHL), Material Extrusion (MEX), outlining their operational principles, typical application domains, and suitability for biomedical use. Among these, selective laser melting (SLM), also known as laser powder bed fusion (PBF-LB), is identified as the most widely adopted approach for NiTi medical device manufacturing due to its high geometric resolution and ability to produce near-net-shape components. In addition, emerging and non-traditional AM techniques such as binder jetting (BJT), material jetting (MJT), and vat photopolymerization (VPP) are discussed in the context of hybrid and multi-material medical device systems. The effects of each AM process on the microstructural behavior of NiTi are examined. Future perspectives are discussed, focusing on optimized material design, advanced process control, improved manufacturing equipment, and data-driven approaches to accelerate the translation of additively manufactured NiTi into reliable, high-performance biomedical devices.