Microvalve jetting, with its advantages of low cost, ease of operation, high printing speed, and ability to process living cells with high viability, has been primarily used for fabricating high-throughput drug-screening models, in vitro cellular structures for fundamental cell biology research, and cell-laden structures for regenerating tissues or organs in the human body after disease or trauma. This article provides an overview of microvalve jetting of biomaterials, including operational parameters. The jetting technologies covered are inkjet printing, microvalve jetting, and laser-assisted jetting. The parameters covered include nozzle size (nozzle inner diameter), pneumatic pressure, valve-opening time, and printing speed of microvalve jetting. Subsequently, the article discusses biomaterials for microvalve jetting in terms of biomaterial definition, required properties for a suitable biomaterial, currently used biomaterials, and cells and cellular structures. Additionally, applications of microvalve jetting in biomedical engineering are presented, which include cellular and RNA analysis, high-throughput drug screening, and tissue engineering.

The use of 3D bioprinting techniques has contributed to the development of novel cellular patterns and constructs in vitro, ex vivo, and even in vivo. There are three main bioprinting techniques: inkjet printing, extrusion printing (also known as bioextrusion), laser-induced forward transfer (LIFT) printing, which is also known as modified LIFT printing, matrix-assisted pulsed-laser evaporation direct write, and laser-based printing (laser-assisted bioprinting, or biological laser printing). This article provides an overview of the LIFT process, including the LIFT process introduction, different implementations, jetting dynamics, printability phase diagrams, and printing process simulations. Additionally, materials involved during LIFT are introduced in terms of bioink materials and energy-absorbing layer materials. Also, the printing of single cells and 2D and 3D constructs is introduced, showcasing the current state of the art with the ultimate goal for tissue- and organ-printing applications.

The application of three-dimensional printers can be revolutionary as a tool for the customization and personalization of pharmaceutical dosage forms. The areas of 3D printing applicable to pharmaceutical manufacturing can be segregated into three categories: extrusion technologies, powder-bed fusion, and stereolithography. Common extrusion-based technologies are fused deposition modeling and pressure-assisted microsyringe; powder-bed fusion is separated by binder jet and selective laser sintering. The synergies between pharmaceutical, or active pharmaceutical ingredient (API), and polymer printing are discussed in this article, with particular attention to how the incorporation of small-molecule APIs changes the material selection, design considerations, processing parameters, and challenges associated with each technology.

This article focuses on a variety of laser beam machining (LBM) operations of aluminum and its alloys, namely, laser cutting, laser drilling, laser milling, laser turning, laser grooving, laser scribing, laser marking, and laser micromachining. It presents different approaches for carrying out machining operations, laser processing parameters, efficiency and accuracy of the process, and the effect of laser processing parameters on the quality of the machined surface. The article provides an overview of the various conventional (chip forming) and nonconventional machining techniques employed for aluminum-based materials. A comparison of the various aspects of LBM with other non-conventional techniques is also presented. The article also describes the features of LBM techniques employed for aluminum and its alloys for different types of machining.

This article describes the use of conventional machining techniques, laser cutting and water-jet cutting for producing finished composite parts. It explains two representative polymer-matrix composites--graphite and aramid composites--and discusses the machining and drilling problems such as delamination and fiber or resin pullout. The article describes machining and drilling techniques and the necessary tools and cutting parameters. It presents a description of laser cutting. The article also provides information on the advantages, disadvantages, cutting characteristics, and applications of water-jet cutting and abrasive water-jet cutting.

Cutting with lasers is accomplished with carbon dioxide (CO 2 ) and neodymium: yttrium-aluminum-garnet (Nd:YAG) lasers. This article provides a description of the process variables and principles of laser cutting. It discusses the three basic types of CO 2 gas lasers, namely, slow axial flow, transverse flow, and fast axial flow and reviews the applications of Nd:YAG laser. The article describes the basic parameters in the laser-cutting process: beam quality, power, travel speed, nozzles design, and focal-point position. Several material conditions that affect the quality of the laser cut are also discussed. The article provides information on the basic laser-cutting system and its optional equipment. A general description of how well each metal group can be cut is also provided.

Laser has found its applications in cutting, drilling, and shock-peening operations of manufacturing industry because of its accurate, safe, and rapid cutting property. This article provides an account on the fundamental principles of laser cutting (thermal), drilling, and shock-peening processes of which emphasis is placed on thermal laser cutting. It details the principal set-up parameters, such as the laser beam output, nozzle design, focusing optic position and characteristics, assist gases, surface conditions, and cutting speed. A discussion on the types of gas, supply system, purity level, and flow rates of lasing and assist gases is also provided. The article also describes the metallurgies and other key material considerations that impact laser-cutting performances and includes examples of laser cutting of nonmetal materials.

This article discusses the basic operating principles, industrial applications, and advantages as well as the parameters influencing the process of laser-induced forward transfer (LIFT) of solid materials, liquid materials, laser-absorbing layers, intact structures, and metallic 3D microstructures in additive manufacturing.

Laser beam machining removes, melts, or thermally modifies a material by focusing a coherent beam of monochromatic light on the workpiece. This article describes the principal lasers used in metal processing: neodymium-glass, carbon dioxide, and neodymium-doped yttrium aluminum garnet lasers. It discusses the operating parameters of concern in percussion drilling and trepanning. The process variables in surface treatment and laser cutting, as well as the operating parameters of concern in laser welding are reviewed. The article also explains the various categories of surface treatment: heat treating, cladding, surfacing, glazing, and marking.

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 begins with a discussion on the energy sources used for thermal forming. These include electric induction coil, gas flame, plasma torch, and laser beam. The article discusses the mechanisms of forming and different modes of deformation. It describes the effect of process and material parameters on forming and the effect of metallurgical changes on mechanical property and microstructure of stainless steel. The article concludes with information on the applications of thermal forming.

Of the seven additive manufacturing (AM) processes, this article focuses on the vat photopolymerization, or simply vat polymerization, process, while briefly discussing the other six AM processes. Vat polymerization and its characteristics, AM applications in medical fields, and the regulatory challenges of vat polymerization-based bioprinting are presented.

This article discusses the operating principles, types, and applications of shearing and slitting of different forms of steel, including plates, flat sheets, bars, coiled sheet and strips. In addition, it provides a detailed account of the cutting methods such as oxyfuel gas cutting, plasma arc cutting, oxygen arc cutting, laser beam cutting, and air carbon arc cutting and gouging, describing their process capabilities, equipment used, operating principles and parameters, and factors affecting their efficiency.

This article presents a general understanding of causes and possible solutions for defects in the most common metal additive manufacturing (AM) processes: laser powder-bed fusion (L-PBF), laser directed-energy deposition (DED-L), and binder jetting (BJ).

Lasers evolved as a versatile materials processing tool due to their advantages such as rapid, reproducible processing, chemical cleanliness, ability to handle variety of materials, and suitability for automation. This article focuses on state-of-the-art laser applications to improve tribological performance of structural materials in lubricated and nonlubricated environments. It discusses the fundamentals of various laser materials interactions and reviews laser-based surface-modification strategies, including laser surface heating and melting, laser-synthesized coatings, and laser-based design approaches such as laser patterning and dimpling. Laser-surface modification of novel materials, such as high-entropy alloys and metallic glasses, is explored. The article provides an overview of hybrid techniques involving laser as a secondary tool, as well as a discussion on the improved capabilities of laser surface engineering for tribological applications by means of integrated computational process modeling.

This article is a comprehensive collection of summary charts that provide data and information that are helpful in considering and selecting applicable processes alternative to the conventional material-removal processes. Process summary charts are provided for electrochemical machining, electrical discharge machining, chemical machining, abrasive jet machining, laser beam machining, electron beam machining, ultrasonic impact grinding, hydrodynamic machining, thermochemical machining, abrasive flow machining, and electrical discharge wire cutting.

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.