Three-dimensional printing technology has fundamentally revolutionized the product development processes in several industries. Three-dimensional printing enables the creation of tailored prostheses and other medical equipment, anatomical models for surgical planning and training, and even innovative means of directly giving drugs to patients. Polymers and their composites have found broad usage in the healthcare business due to their many beneficial properties. As a result, the application of 3D printing technology in the medical area has transformed the design and manufacturing of medical devices and prosthetics. Polymers and their composites have become attractive materials in this industry because of their unique mechanical, thermal, electrical, and optical qualities. This review article presents a comprehensive analysis of the current state-of-the-art applications of polymer and its composites in the medical field using 3D printing technology. It covers the latest research developments in the design and manufacturing of patient-specific medical devices, prostheses, and anatomical models for surgical planning and training. The article also discusses the use of 3D printing technology for drug delivery systems (DDS) and tissue engineering. Various 3D printing techniques, such as stereolithography, fused deposition modeling (FDM), and selective laser sintering (SLS), are reviewed, along with their benefits and drawbacks. Legal and regulatory issues related to the use of 3D printing technology in the medical field are also addressed. The article concludes with an outlook on the future potential of polymer and its composites in 3D printing technology for the medical field. The research findings indicate that 3D printing technology has enormous potential to revolutionize the development and manufacture of medical devices, leading to improved patient outcomes and better healthcare services.

Titanium (Ti) alloys are widely used in industrial manufacturing, medical treatment, vehicles, and other fields. When welded with other alloys, due to great differences in physical and chemical properties of these materials, cracks easily appear in the joint, and obtaining stable welded joints is difficult. Results show that brittle intermetallic compounds (IMCs) formed in the welding process could reduce the plasticity of the joint. This review aimed to provide a comprehensive overview of the recent progress in welding and joining of Ti alloy and light alloys and to introduce current research and application. The methods available for welding Ti alloy and light alloys included fusion welding, brazing, diffusion bonding, friction welding and reactive joining. In this study, control methods of brittle IMCs in the welding process of Ti and other alloys and various improvement measures studied at home and abroad are described.