Additive manufacturing (AM), or three-dimensional (3D) printing, has been widely used for biomedical devices due to its higher freedom of design and its capability for mass customization. Additive manufacturing can be broadly classified into seven categories: binder jetting, directed energy deposition (DED), material extrusion, material jetting, powder-bed fusion (PBF), sheet lamination, and vat photopolymerization. Due to their capability for manufacturing high-quality parts that are fully dense, PBF and DED are the most widely used groups of AM techniques in processing metals directly. In this article, the processing of titanium and its alloys by PBF and DED is described, with a specific focus on their use in biomedical devices. The article then covers the density and mechanical properties of both commercially pure titanium and titanium-aluminum-vanadium alloy. Lastly, the challenges and potential of using new titanium-base materials are discussed.

This article focuses on the directed-energy deposition (DED) additive manufacturing (AM) technique of biomedical alloys. First, it provides an overview of the DED process. This is followed by a section describing the design and development of the multiphysics computational modeling of the layer-by-layer fusion-based DED process. A brief overview of the primary governing equations, boundary conditions, and numerical methods prescribed for modeling laser-based metal AM is then presented. Next, the article discusses fundamental concepts related to laser surface melting and laser-assisted bioceramic coatings/composites on implant surfaces, with particular examples related to biomedical magnesium and titanium alloys. It then provides a review of the processes involved in DED of biomedical stainless steels, Co-Cr-Mo alloys, and biomedical titanium alloys. Further, the article covers novel applications of DED for titanium-base biomedical implants. It concludes with a section on the forecast of DED in biomedical applications.

Metallic alloys that are typically used for medical purposes include stainless steels, Ti-6Al-4V, and Co-Cr-Mo. This article discusses the relative merits of each of these alloys. The utilization of stainless steels in the biomedical industry, especially in relation to the additive manufacturing (AM) process, is the main focus of this article. The characteristics of various stainless steels are described subsequently, and the categories that are of relevance to the biomedical industry are identified. The types of stainless steels covered are austenitic, ferritic, martensitic, duplex, and precipitation-hardened stainless steels. The article discusses the potential benefits of AM for biomedical devices. It describes the types of AM processes for stainless steels, namely binder jet, directed-energy deposition, and laser powder-bed fusion. The article reviews the AM of austenitic, martensitic, and PH stainless steels for biomedical applications. In addition, the challenges and obstacles to the clinical use of AM parts are covered.

This article discusses some of the additive manufacturing (AM) based fabrication of alloys and their respective mechanical, electrochemical, and in vivo performance. Firstly, it briefly discusses the three AM techniques that are most commonly used in the fabrication of metallic biomedical-based devices: binder jetting, powder-bed fusion, and directed-energy deposition. The article then characterizes the electrochemical properties of additive-manufactured/processed cobalt-chromium alloys. This is followed by sections providing an evaluation of the biological response to CoCr alloys in terms of the material and 3D printing fabrication. Discussion on the biological response as a function of direct cellular activity on the surface of CoCr alloys in static conditions (in vitro), in dynamic physiological conditions (in vivo), and in computer-simulated conditions (in silico) are further discussed in detail. Finally, the article provides information on the qualification and certification of AM-processed medical devices.

The article presents an in-depth discussion on the various additive manufacturing techniques such as binder jetting, directed-energy deposition, material extrusion, material jetting, powder-bed fusion, sheet lamination, and vat polymerization processes. This article then discusses the different critical material aspects of additively manufactured medical devices, beginning with the preprinting phase (material consistency and recycling), the printing phase (build orientation), and the postprinting phase (part evaluation, biocompatibility, and sterilization) with supporting materials.

Additive manufacturing (AM) techniques include powder-bed fusion (PBF), directed-energy deposition, binder jetting (BJ), extrusion-based desktop, vat photopolymerization, material jetting, and sheet lamination. The development of suitable powders for AM is a challenging task because of critical design parameters including chemical composition, flowability of powders, and melt surface tension. This article explains the fabrication methods of metal and novel alloy powders for medical applications. The development of zirconium alloy powder for laser-PBF is introduced as a case study.

This article provides an overview of metal additive manufacturing (AM) processes and describes sources of failures in metal AM parts. It focuses on metal AM product failures and potential solutions related to design considerations, metallurgical characteristics, production considerations, and quality assurance. The emphasis is on the design and metallurgical aspects for the two main types of metal AM processes: powder-bed fusion (PBF) and directed-energy deposition (DED). The article also describes the processes involved in binder jet sintering, provides information on the design and fabrication sources of failure, addresses the key factors in production and quality control, and explains failure analysis of AM parts.

Additive manufacturing is a collection of manufacturing processes, each of which builds a part additively based on a digital solid model. The solid model-to-additive manufacturing interface and material deposition are entirely computer-controlled. The traditional additive manufacturing applications have been used for low production runs of parts with complex shapes and geometric features. Additive manufacturing is also used for topology optimization and it impacts the process and supply chain. This article discusses processes, including vat photopolymerization, material jetting, powder bed fusion, directed energy deposition, material extrusion, binder jetting, and sheet lamination.

This article introduces the design and manufacturing implications of additive manufacturing (AM) on part characteristics as well as on design opportunities and on manufacturing practices, supply chains, and even business models. In addition, it describes how they relate to the fundamental nature of AM processes and discusses the characteristics and purposes of AM processes and the parts they fabricate.

Powder bed fusion (PBF) of polymers is a collection of additive manufacturing processes that melt and fuse polymer in a powder bed. This article provides a complete suite of materials and processes involved in PBF of polymers. The discussion includes details of thermal and manufacturing issues, and safety, postprocessing, and finishing considerations, as well as of principal defects in PBF polymer parts and the mechanical properties of the parts produced by PBF. The article provides case studies on the applications of polymer PBF.

During metal powder production, powder and/or dust handling, compaction, and part finishing operations, many safety and environmental risks exist. This article is a detailed account of the types of safety hazards that can exist and the issues that occur during metal powder handling, as well as recommendations and strategies that can be employed to both prevent and protect against damaging effects from powder exposure, fire and/or explosions, or environmental impact events.

Fusion-based additive manufacturing (AM) processes rely on the formation of a metallurgical bond between a substrate and a feedstock material. Energy sources employed in the fusion AM process include conventional arcs, lasers, and electron beams. Each of these sources is discussed, with an emphasis on their principles of operation, key processing variables, and the influence of each source on the transfer of heat and material. Common energy sources used for metals AM processes, particularly powder-bed fusion and directed-energy deposition, are also discussed. Brief sections at the end of the article discuss the factors dictating the choice of each of these energy sources and provide information on alternative sources of AM.

Aerosol jet printing (AJP) can digitally fabricate intricate patterns on conformal surfaces with applications that include flexible electronics and antennas on complex geometries. Given the potential performance and economic benefits, aerosol jetting was studied and compared with the well-known and competing inkjet printing (IJP). More than 35 of the most relevant, highly cited articles were reviewed, focusing on applications requiring fine features on complex surfaces. The following performance indicators were considered for the comparison of AJP and IJP, because these aspects were the most commonly mentioned within the included articles and were identified as being the most relevant for a comprehensive performance assessment: printing process, line width, overspray, complex surface compatibility, diversity of printable materials, and deposition rate. This article is an account of the results of this comparison study in terms of printing capabilities, ink requirements, and economic aspects.

This article discusses the advantages, limitations, and applications of material jetting of ceramics, focusing on two primary methods of droplet formation: continuous stream and drop on demand (thermal and piezoelectric) ink jetting processes.

Hot isostatic pressing (HIP) is widely used within the additive manufacturing (AM) industry to improve material performance and ensure quality. This article is a detailed account of the HIP process, providing information on its equipment set up and discussing the applications, economics, and advantages of the process. The discussion also covers the use of HIP for additively manufactured material to eliminate internal defects, the HIP parameters required to eliminate internal defects, and the influence of HIP on the microstructure and properties of HIP additively manufactured material.

Vat polymerization (VP) is an additive manufacturing (AM), or three-dimensional (3-D) printing process in which 3-D objects are produced by hardening a liquid polymer into the desired shape. With the introduction of new materials and improvements in material properties, VP offers a good alternative for AM for low-volume production. This overview of the VP process begins with an introduction to two main processes of VP, namely stereolithography apparatus and digital light processing, and then moves on to discuss the characteristics of the feedstocks used as well as their selection criteria. The article then covers safety issues associated with feedstock handling and the manufacturing constraints related to part orientation and design, providing some key tips for VP support structures. This is followed by a discussion on postprocessing/finishing of VP parts. A brief concluding section considers some special topics related to AM process.

This article is a detailed account of the advantages, disadvantages, and applications of microdispensing processes used in electronics manufacturing industries. The discussion covers various approaches to control material flow, namely time pressure, auger, positive displacement, and progressive cavity pump dispensing. The concept of valving to control starting and stopping is also discussed. The applications include printing solders in microelectronic packaging, printing to pads, printing conductive patterns for antennas, printing active circuits, printing on flexible surfaces, and structural printing.

The additive manufacturing technologies in the casting of precious metals are divided into two groups: indirect metal methods and direct metal methods. Besides providing a process overview of both of these methods, the focus of this article is on the characteristics, process steps, applications, and advantages of direct metal methods, namely laser melting, material extrusion, binder jetting, material jetting, and vat photopolymerization methods.

This article provides an overview of the implementation of wire embedding with ultrasonic energy and thermal embedding for polymer additive manufacturing, discussing the applications and advantages of the technique. The mechanical and electrical performance of the embedded wires is compared with that of other conductive ink processes in terms of electrical conductivity and mechanical strength.

Directed-energy deposition (DED) is a kind of additive manufacturing (AM) technology based on synchronous powder feeding or wire feeding. This article provides a comprehensive coverage of DED for ceramic AM, beginning with an overview of DED equipment setup, followed by a discussion on DED materials and the DED deposition process. The bulk of the article is devoted to the discussion on the microstructure and properties of oxide ceramics, namely alumina and zirconia ceramics.