This article discusses the functions of lubricants to prevent premature failure of rolling element bearings and the advantages of fluid lubrication. It describes the composition of refined mineral oil for rolling bearing applications. The article reviews the types and properties of nonpetroleum oils, such as polyglycols, phosphate esters, silicone fluids, dibasic acid esters, and fluorinated polyethers. It discusses the properties of greases, including grease speed limits, grease composition, relubrication intervals, corrosion prevention behavior, and grease compatibility. The article concludes with a discussion on polymeric lubricants and solid lubricants.

This article tabulates materials that are known to have been used in orthopaedic and/or cardiovascular medical devices. The materials are grouped as metals, ceramics and glasses, and synthetic polymers in order. These tables were compiled from the Medical Materials Database which is a product of ASM International and Granta Design available by license online and as an in-house version. The material usage was gleaned from over 24,000 U.S. Food and Drug Administration (USFDA), Center for Devices and Radiological Health, Premarket notifications (510k), and USFDA Premarket Approvals, and other device records that are a part of this database. The database includes other material categories as well. The usage of materials in predicate devices is an efficient tool in the material selection process aiming for regulatory approval.

The function of lubricants is to control friction and wear in a lubricating system containing machine elements such as gears and bearings. This article discusses the basic properties of lubricants to help scientists and engineers understand the principles behind lubricant selection. It reviews the functions of additives, such as friction modifiers, antiwear additives, viscosity modifiers, corrosion inhibitors, oxidation inhibitors, dispersants, and detergents. The article discusses the physical properties of liquid lubricants and the performance characteristics of lubricants. It describes the most common lubricant categories and provides information on the health and safety aspects of using liquid lubricants. The article concludes with a discussion on the lubricant-application method that plays a vital role in how the lubricant functions.

This article provides an overview of the interfacial interactions with a lubricant film between a die and a metal, lubricant mechanisms, chemistry, qualification testing, application methods, and property test methods. It focuses on sheet metal-forming operations, although the discussions are relevant to metal-forming operations in general. The article also deals with lubricant selection as influenced by the metal to be formed and particular sheet-metal forming operations. The article also discusses some aspects of microbiology and toxicity in lubricants.

This article lists functions of lubricants common to the majority of applications and processes. It discusses the lubricant candidates widely used in forging: conversion coatings with soaps (stearate compounds) and molybdenum disulfide for cold forging; oil-based thick, film oil or polymerbased lubricants and molybdenum disulfide for warm application; graphite suspensions in oil or water for hot forging steels; and glass films for titanium and superalloys hot forgings. The article describes the applications of lubricants in warm extrusion and forging, hot forging of steel, hot forging of aluminum, isothermal and hot die forging, and the extrusion of steel.

Due to its layer-by-layer process, 3D printing enables the formation of complex geometries using multiple materials. Three-dimensional printing for bone tissue engineering is called bioprinting and refers to the use of material-transfer processes for patterning and assembling biologically relevant materials, molecules, cells, tissues, and biodegradable biomaterials with a prescribed organization to accomplish one or more biological functions. Currently, 3D bioprinting constructs can be classified into two categories: acellular and cellular. This article introduces and discusses these two approaches based on the suitable materials for these constructs and the fabrication processes used to manufacture them. The materials are grouped into polymers, metals, and hydrogels. The article also summarizes the commonly used 3D printing techniques for these materials, as well as cell types used for various applications. Lastly, current challenges in tissue engineering are discussed.

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.

Soldering involves heating a joint to a suitable temperature and using a filler metal (solder) that melts below 450 deg C (840 deg F). Beginning with an overview of the specification and standards and applications, this article discusses the principal levels and effects of the most common impurity elements in tin-lead solders. It describes the various processes involved in the successful soldering of joints, including shaping the parts to fit closely together; cleaning and preparing the surfaces to be joined; applying a flux; assembling the parts; and applying the heat and solder.

Additives for plastics and elastomers are used to increase the ease of processing and to improve the properties of the final product. Additives improve processing characteristics by increasing lubricity and by stabilizing the polymer. Additives that improve properties include those that decrease static charge development and microbial activity and those that improve flame retardation characteristics, color, light stability, impact resistance, density and mechanical properties. This article focuses on the additives for polymers and elastomers that are used for improving processing--blowing agents, mold-release agents, lubricants, plasticizers, and heat stabilizers--and for improving properties antimicrobials, antioxidants, antistatic agents, colorants, fillers and fiber reinforcements, flame retardants, impact modifiers, light stabilizers, plasticizers, and heat stabilizers. Furthermore, it discusses the method for addition of these additives and the problems faced during compounding.

This article provides an overview of common quenching media, the factors involved in the mechanism of quenching, and process variables, namely, surface condition, mass and section size of the workpiece, and flow rate of the quenching liquid. It describes the methods of quenchant characterization using hardening-power and cooling-power tests. The article discusses the fundamentals involved in heat-transfer coefficient and heat flux of quenching processes. This discussion is followed by various actual examples of applications of these methods using simplified equations. Quenchant evaluation, classification, selection, and maintenance are reviewed in detail. The article addresses the various reasons for quench oil variability and complications due to aging and contamination.

This article outlines the selection criteria for choosing an implant material for biomedical devices in orthopedic, dental, soft-tissue, and cardiovascular applications. It details the development of various implants, such as metallic, ceramic, and polymeric implants. The article discusses specific problems associated with implant manufacturing processes and the consequent compromises in the properties of functionally graded implants. It describes the manufacturing of the functionally-graded hip implant by using the LENS process. The article reviews four different types of tissue responses to the biomaterial. It discusses the testing methods of implant failure, such as in vitro and in vivo assessment of tissue compatibility.

This article begins with a description of extrusion-based bioprinting for tissue scaffold fabrication. It also examines various extrusion-based bioprinting processes and related tissue scaffolding strategies, presents the selection criteria of various bioinks with various polymers and their printed scaffolds for applications in tissue engineering and regenerative medicines, and provides future research recommendations to address the shortcomings and issues found in current extrusion-based bioprinting processes.

Powder-bed fusion (PBF) is a group of additive manufacturing (AM) processes that includes selective laser sintering, selective laser melting, and electron beam melting. This article explains the processes and parameters of PBF systems that are used for biomedical applications. It also presents the desirable properties of biomedical devices and the advantages of using PBF systems for biomedical applications.

Cutting fluids play a major role in increasing productivity and reducing costs by making possible the use of higher cutting speeds, higher feed rates, and greater depths of cut. After listing the functions of cutting fluids, this article then covers the major types, characteristics, advantages and limitations of cutting and grinding fluids, such as cutting oils, water-miscible fluids, gaseous fluids, pastes, and solid lubricants along with their subtypes. It discusses the factors considered during the selection of cutting fluid, focusing on machinability (or grindability) of the material, compatibility (metallurgical, chemical, and human), and acceptability (fluid properties, reliability, and stability). The article also describes various application methods of cutting fluids and precautions that should be observed by the operator.

This article discusses the functions and chemistry of metal cutting or grinding fluids. It reviews the choice of cutting or grinding fluids that is influenced by the workpiece material, fluid characteristics, and machining operation. The article describes two application methods of cutting or grinding fluids: flooding and misting. It discusses and lists the American Society for Testing and Materials standard test procedures used in establishing control of cutting and grinding fluids. The article provides information on the storage, distribution, cleaning, and disposal of cutting and grinding fluids. It concludes with information on the health implications and biology of cutting fluids.

This article provides highlights of the general process and workflow of creating a 3D-printed model from a medical image and discusses the applications of additively manufactured materials. It provides a brief background on Food and Drug Administration (FDA) classification and regulation of medical devices, with an emphasis on 3D-printed devices. Then, the article discusses two broad applications of 3D printing in craniofacial surgery: surgery and education. Next, it discusses, with respect to surgical applications, preoperative planning, use in the operating room, surgical guides, and implants. The article includes sections on education that focus on the use of 3D-printed surgical simulators and other tools to teach medical students and residents. It briefly touches on the FDA regulations associated with the respective application of 3D printing in medicine. Lastly, the article briefly discusses the state of medical billing and reimbursement for this service.

This article discusses the family characteristics, commercial forms, applications, resin grades, and mechanical and physical properties of traditional engineering thermoplastics in their neat (unmodified) form and as compounds and composites, namely, acrylonitrile-butadiene-styrenes, acrylics, high-density polyethylenes, reinforced polypropylenes, high-impact polystyrenes, polyvinyl chloride, styrene-acrylonitriles, and styrene-maleic anhydrides.

Induction heating for hardening of steels has advantages from the standpoint of quenching because parts are individually processed in a controlled manner. This article provides information on the effect of agitation, temperature, hardening, residual stresses, and quenching media, on quenching. It also describes various quenching methods for steel induction heat treating, namely, spray quenching, immersion quenching, self or mass quenching, and forced air quenching. The article also reviews quench system design and quenchants and their maintenance.

This article provides a brief introduction to lubrication as a method to reduce friction between two surfaces. It discusses the surface characteristics of parts and explores how lubrication helps separate two contacting surfaces and thereby decreases the coefficient of friction. The article details the classifications of lubrication regimes, namely, boundary, mixed, hydrodynamic, and elastohydrodynamic lubrications. It discusses the various types of lubricant materials and additives, including liquid lubricants, solid lubricants, gaseous lubricants, greases, green lubricants, and nanomaterials. The article also reviews the properties of lubricants. It describes the tribological evaluation of lubricants, including stribeck test, four-ball test, block-on-ring test, pin-in-vee test, and reciprocating motion test.