Progress in Additive Manufacturing

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, presenting the operational principles, typical application domains, and suitability for biomedical use of several AM technologies, including powder bed fusion (PBF), directed energy deposition (DED), sheet lamination (SHL), and material extrusion (MEX). Selective laser melting (SLM), recognized for its high geometric resolution, emerges as the most widely adopted method for NiTi medical device manufacturing. Additionally, emerging techniques like binder jetting (BJT), material jetting (MJT), and vat photopolymerization (VPP) are explored in the context of hybrid and multi-material medical systems. The effects of each AM process on the microstructural behavior of NiTi are examined, and future perspectives on optimized material design, process control, and data-driven approaches are discussed to accelerate the transition of additively manufactured NiTi into reliable biomedical devices. Overall, this review serves as a comprehensive guide for future research and process selection in the field.