Powder metallurgy compacting presses usually are mechanically or hydraulically driven, but they can incorporate a combination of mechanically, hydraulically, and pneumatically driven systems. This article provides a comparison of mechanical and hydraulic presses based on the cost, production rate, and machine overload protection. The article lists the classification of powder metallurgy parts based on complexity of shapes as suggested by the Metal Powder Industries Federation, such as Class I parts, Class II parts, Class III parts, and Class IV parts. It describes rigid tooling compaction and details the powder-fill ratio considerations for these classes. The article elaborates on the types of tooling systems and presses used for these classes. Some important factors and components used in designing a tool are also described. Finally, the article considers tool materials, including punches, core rods, and punch clamp rings.

Power metallurgy (PM) is a process of shaping metal powders into near-net or net shape parts combined with densification or consolidation processes for the development of final material and design properties. This article introduces the general considerations, models, and applications in the modeling of PM processes. It describes the PM process in terms of powder compaction and sintering. The article schematically illustrates powder injection molding for the production of plastic parts and describes PM process models such as discrete-element model (DEM), linear continuum model, and nonlinear continuum model. It concludes with information on the application of press and sinter modeling to practical problems in PM.

This article focuses on the axisymmetric 2.5-dimensional approach used in metal powder injection molding (PIM) simulations. It describes three stages of PIM simulations: filling, packing, and cooling. The article discusses the process features of numerical simulation of PIM, such as filling and packing analysis, cooling analysis, and coupled analysis between filling, packing, and cooling stages. It explains the experimental material properties and verification for filling, packing, and cooling stages in the PIM simulations. The article presents simulation results from some of the 2.5-dimensional examples to demonstrate the usefulness of the computer-aided engineering analysis and optimization capability of the PIM process.

This article focuses on direct extrusion processing where metal powders undergo plastic deformation, usually at an elevated temperature, to produce a densified and elongated form having structural integrity. It provides information on the basic powder extrusion processes and the mechanics of extrusion. The article also examines specific extrusion practices for the production of wrought material from powder stock and provides examples of materials processed by powder extrusion.

This article discusses the process details of metal powder injection molding of microcomponents and the powder particle characteristics of feedstock and property requirements of binders. It reviews important characteristics to be considered in the processing steps: venting, channel diameters, binder segregation, binder degradation, feedstock supply, temperature control, demolding, debinding, and sintering. Finally, the article provides information on powder injection molding mold-filling simulation and two-component powder injection molding, offering a method for high-volume production of microcomponents made of multifunctional materials.

This article describes the methods for determining the flow rate of metal powders. It examines the factors affecting flow rate, apparent density, and angle of repose of metal powders. The article reviews the frictional properties, cohesive strength, frictional properties, tap density, and compressibility of metal powders. It explains the mechanisms of powder segregation. The article provides information on green strength and springback value of rectangular test bar. It concludes with a discussion on the chemical composition of metal powders.

Development of the properties of copper powder metallurgy parts is affected by pressing and sintering processes used in the production of components, such as contacts, carbon brushes, and friction materials. This article briefly describes the powder properties of copper and discusses the roles of lubricant and compaction dies in pressing of copper powders. It explains the structural defects that originate during the compaction process of PM parts. The article also provides information on sintering, re-pressing, and re-sintering of copper PM parts.

Prealloyed (PA) powder metallurgy is a technique where complex near-net shape titanium aircraft components are fabricated with low buy-to-fly ratios. This article describes the physical principle, mechanism, and simulation and modeling of metal can and hot isostatic pressing (HIP) processes involved in the PA powder metallurgy technique. It discusses the technical problems addressed in shape control and their solutions for understanding the advantages of powder metallurgy HIP.

Bronze and brass alloys are two key classes of materials in copper-base powder metallurgy applications. They are often compacted using mechanical or hydraulic pressing machines. This article provides an overview of the powder pressing process, providing information on the powder properties of bronze and brass and the roles of lubricant and compaction dies in the pressing process. It discusses the structural defects that originate during the compaction process. The article also describes the major factors that influence the sintering response in bronze, prealloyed bronze, brass, and nickel-silver.

Mounting of the specimen is often desirable or necessary for handling and metallographic polishing after the specimen is cut into an appropriate size. This article illustrates the different mechanical clamps used in mounting small specimens. It provides useful information on compression molded mounts, which are molded with thermoplastic and thermosetting resins. The article reviews several resins and their key factors, which help in the selection of the most appropriate mounting method and resin. It also discusses the characteristics of plastic mounting materials. The article provides information on the molds and resins used for castable mounts, vacuum treatment of mounts, special mount arrangements, and mount marking and storage.

This article describes the unique aspects of cold isostatic pressing (CIP) in comparison with die compaction, for powder metallurgy parts. It details the components of CIP equipment, including pressure vessels, pressure generators, and tooling material. The article reviews the part shapes and their influence in determining tap density of the filled mold. It provides a discussion on process parameters, such as dwell time, depressurization rate, evaluation of green strength and density, and thermal processing, and illustrates a process flowchart for the production of CIP parts.

This article discusses metal powder processing via hot isostatic pressing (HIP) and HIP cladding when metal powders are being employed in the cladding process. It traces the history of the process and details the equipment, pressing cycle, and densification mechanisms for HIP. The article describes the available process routes for fabricating products using HIP and the steps involved in the production of a part via direct HIP of encapsulated gas-atomized spherical powder. It concludes with information on the microstructures of 316L stainless steel HIP powder metallurgy valve body and a list of the mechanical properties of several powder metallurgy alloys.

This article describes part selection, feedstock (powders and binders) characteristics and properties, tool design, and material and tooling for fabrication of metal powder injection molding (MIM) machines. It discusses the process parameters, operation sequence, molding machines, debinding techniques, consolidation (sintering) techniques, advantages, and limitations of MIM.

This article describes two rapid tooling technologies, namely, direct rapid tooling and indirect rapid tooling, for forging-die applications. Commonly used direct rapid tooling technologies include selective laser sintering, three-dimensional printing, and laser-engineered net shape process. The indirect rapid tooling technologies include 3D Keltool process, hot isostatic pressing, rapid solidification process tooling, precision spray forming, and radially constricted consolidation process.

The two most important classes of materials that are manufactured via infiltration methods are copper- and silver-infiltrated refractory metals and refractory carbides, and copper-infiltrated steels. This article focuses on copper-infiltrated steels and discusses the basic requirements for infiltration, which is a technique that is only applicable to material systems that meet certain requirements. It addresses these requirements and describes the conventional (partial) infiltration process of powder metallurgy (PM) steel. The materials used in the process, such as matrix and infiltrant, are discussed. The article also details several criteria used to evaluate the performance of an infiltration process. It concludes with information on alloy steels and fully infiltrated steels.

According to International Organization for Standardization (ISO)/ASTM International 52900, additive manufacturing (AM) can be classified into material extrusion, material jetting, vat photo polymerization, binder jetting, sheet lamination, powder-bed fusion (PBF), and directed-energy deposition. This article discusses the processes involved in polymer powder 3D printing using laser fusion/ sintering and fusing agents and energy, as well as the thermally fused PBF. It provides information on polymer powder parameters and modeling, the powder-handling system, powder characterization, the flowability of powder feedstock, and polymer part characteristics. The article describes the types of polymers in PBF, the processes involved in powder recycling, and the prospects of PBF in AM. In addition, the biomedical application of polyether ether ketone (PEEK) is also covered.

Milling of materials, whether hard and brittle or soft and ductile, is of prime interest and of economic importance to the powder metallurgy (PM) industry. This article discusses the principles of milling, milling parameters, and the powder characteristics required for the process. It discusses the changes in powder particle morphology that occur during milling of metal powders produced by various processes such as microforging, fracturing, agglomeration, and deagglomeration. The article also provides useful information on milling equipment such as tumbler ball mills, vibratory ball mills, attrition mills, and hammer and rod mills.

Ceramic-forming processes usually start with a powder which is then compacted into a porous shape, achieving maximum particle packing density with a high degree of uniformity. This article compares and contrasts several forming processes, including mechanical consolidation, dry pressing, cold isostatic pressing, slip casting, tape casting, roll compaction, extrusion, and injection molding. It describes the advantages, equipment and tooling, and material requirements of green machining, the machining of ceramics in an unfired state with the intent of producing parts as close to as possible to their final shape. The article also provides useful information on drying methods, shrinkage, and defects as well as the removal of organic processing aids such as dispersants, binders, plasticizers, and lubricants.

Hydroxyapatite (HA) is one of the most popular materials in tissue scaffold engineering due to its similarity to the nature of human bone; it accounts for more than half of the total weight of the latter. Selective laser sintering (SLS) is an additive manufacturing method that is used in producing tissue engineering parts from HA feedstocks. This article provides a brief overview of the process itself, along with a detailed review of HA-based tissue engineering applications using SLS. Discussion on the various polymer composites is presented. A detailed overview of selected publications on HA-based SLS studies is listed, which provides insight regarding technical aspects of processing HA powder feedstocks.

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.