The horsepower requirements to cut various metal alloys provide an indication of the relative ease and cost of machining, but several other important factors include cutting tool material, chip formation, cutting fluids, cutting tool wear, surface roughness, and surface integrity. This article reviews these general machining factors as well as specific cutting tool and cutting parameters for the six basic chip-forming processes of turning, shaping, milling, drilling, sawing, and broaching. Best practices for each of the six chip-forming processes are suggested for optimized machining of aluminum alloys. The article lists the inherent disadvantages of machining processes that involve compression/shear chip formation. It discusses the machining of aluminum metal-matrix composites and nontraditional machining of aluminum, such as abrasive jet, waterjet, electrodischarge, plasma arc, electrochemical, and chemical machining.

Nanotechnology and smart-coating technologies have been reported to show great promise for improved performance in critical areas such as corrosion resistance, durability, and conductivity. This article exemplifies nanofilms and nanomaterials used in coatings applications, including carbon nanotubes, silica, metals/metal oxides, ceramics, clays, buckyballs, graphene, polymers, titanium dioxide, and waxes. These can be produced by a variety of methods, including chemical vapor deposition, plasma arcing, electrodeposition, sol-gel synthesis, and ball milling. The application of nanotechnology and the development of smart coatings have been dependent largely on the availability of analytical and imaging techniques such as Raman spectroscopy, scanning and transmission electron microscopy, atomic force microscopy, and scanning tunneling microscopy.

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.

Various powder production processes allow precise control of the chemical composition and physical characteristics of powders and allow tailoring of specific attributes for targeted applications. Metal powders are produced by either mechanical methods or chemical methods. The commonly used mechanical methods include water and gas atomization, milling, mechanical alloying, and electrolysis. Some chemical methods include reduction of oxides. This article provides information on the reliable techniques for powder characterization and testing to evaluate the chemical and physical properties of metal powders, both as individual particles and in bulk forms.

This article discusses three types of powder-feeder systems that are commonly used throughout the thermal spray (TS) industry: gravity-based devices, rotating wheel devices, and fluidized-bed systems. It provides information on the various mechanical methods for producing powders, namely, crushing, milling, attriting, and machining. The article describes two prime methods of agglomeration. One method uses a binder by way of agglutination, while the other relies on a sintering operation. The article discusses the technology and principles of the processes that relate to thermal spraying, and offers an understanding for choosing particular feedstock materials that are classified based on the thermal spray process, material morphology, chemical nature of the material, and applications. Sieving, the most common method of separating powders into their size fractions, is also reviewed. The article also provides information on the topical areas and precautions to be undertaken to protect the operator from safety hazards.

The combination of high strength-to-weight ratio, excellent mechanical properties, and corrosion resistance makes titanium the best material choice for many critical applications. This article begins with a description of the historical perspective of titanium casting technology. It discusses the types of molding methods, such as rammed graphite molding and lost-wax investment molding. The article provides information on the casting design, melting, postcasting, and pouring practices. It describes the microstructure and mechanical properties of Ti-6AI-4V alloy. The article examines the product applications of titanium alloy castings. The tensile properties, standard industry specifications, and chemical compositions of various titanium alloy castings are tabulated.

This article describes the machining operations of carbon fiber-reinforced epoxy, or carbon/epoxy thermoset composite materials, such as drilling, reaming, routing, trimming, end milling, slot milling, and facing. It reviews cutting tools for machining, including solid carbide, diamond plated, brazed diamond, diamond coated carbide, and polycrystalline cutting tools. The article also describes cutting tool materials that are used for peripheral milling, face milling, and the trimming of polymer-matrix composites.

This article is a comprehensive collection of machining data, presented in tables, covering most of the commonly used machining operations including turning, face milling, end milling (peripheral), drilling, reaming, and tapping of several materials. It provides starting recommendations for the range of speeds and feeds for various machining operations, parameters for the selection of tool geometry, and guidelines on the selection and identification of cutting fluids.

This article focuses on precision and ultraprecision finish machining techniques that make use of defined cutting edges, such as polycrystalline diamond and cubic boron nitride compacts. The techniques are finish turning, finish broaching, finish milling, and finish drilling.

The combination of high strength-to-weight ratio, excellent mechanical properties, and corrosion resistance makes titanium the best material choice for many critical applications. This article commences with a description of the historical perspective of titanium casting technology. It discusses the various types of molding methods, namely, rammed graphite molding, and lost-wax investment molding. The article provides information on the casting design, melting, and pouring practices, and describes the microstructure, hot isostatic pressing, heat treatment, and mechanical properties of Ti-6AI-4V alloy. It also talks about the chemical milling and weld repair, and describes the product applications of titanium alloy castings. Tensile properties, standard industry specifications, and chemical compositions of various titanium alloy castings are tabulated.

This article describes the selection of tool steels on the basis of specific product applications. It contains tables that list nominal speeds and feeds for the machining of various tool steels. The machining processes include turning, boring, broaching, drilling, reaming, tapping, milling, and sawing. The article explains the machining of the following tool steels: water hardening; types A, D and O cold-work; hot work; high speed, low-alloy special-purpose; and low-carbon mold. It details the machining of tool steel gears. The article also discusses the grinding of tool steels based on steel classification and the effects of steel composition and hardness on grindability. It reviews the types of grinding, namely, surface grinding, cylindrical grinding, centerless grinding, internal grinding, thread grinding, flute grinding, and low-stress grinding. Grinding of types-A, D, F, L, O, P, S and W steels, hot-work steels, and high speed steels, is also detailed.

Powder metallurgy is a near-net shape process capable of producing complex parts with little or no need for secondary operations such as machining, joining, or assembly. However, the inability to produce certain geometrical figures such as transverse holes, undercuts, and threads frequently necessitates some machining, particularly drilling. This article provides a discussion on the measures that can optimize the machining of P/M materials. It reviews the factors influencing machinability of P/M components, including workpiece and tool material properties, cutting conditions, machine and cutting tool parameters as well as some P/M material and production process parameters. These parameters discussed include the particle size, part geometry, porosity, compaction and sintering methods. In addition, the article presents guidelines for the various machining processes, namely, turning and boring, milling, drilling, grinding, reaming, burnishing, tapping, and honing and lapping.

This article discusses the factors influencing cast iron machining and selection of cutting fluid and cutting tool materials. It presents a comparison of machinability of different types of cast iron, namely, gray cast iron, ductile cast iron, and malleable cast iron. In addition, the article provides an overview of different methods used in the machining of cast iron, namely, turning, boring, broaching, planing and shaping, drilling, reaming, counterboring and spotfacing, tapping, milling, grinding, and honing and lapping. Nominal speeds and feeds for the machining of cast iron with single-point and box tools, ceramic tools, high-speed steel, and carbide tools are also tabulated.

This article commences with a schematic illustration of a wide range of cutter configurations available for use in milling operations. It describes the various types of milling machines classified based on the type of construction, such as knee-and-column type, bed-type, planer-type, and special type. The article discusses mechanical-electric, mechanical-hydraulic, mechanical-electric-hydraulic, and numerical control of milling machines. It describes various types of milling cutters, such as peripheral mills, face mills, end mills, and special mills. Milling cutters, such as solid milling cutters, inserted-blade cutters, and indexable-insert cutters, are also discussed. The article explains the capabilities and limitations of peripheral milling, face milling, and end milling methods. It concludes with a comparison of milling with broaching, planing or shaping, and grinding.

This article provides a discussion on cutting tools, their materials and design; cutting fluids; and various aspects of machining operations of heat-resistant alloys, with several examples. Operations such as turning, planing and shaping, broaching, drilling, reaming, counterboring and spotfacing, tapping and thread milling, milling, sawing, and grinding are discussed. Nominal compositions of wrought heat-resistant alloys and nickel-base heat-resistant casting alloys, as well as compositions of cobalt-base heat-resistant casting, iron-base heat-resistant casting, and mechanically alloyed (oxide dispersion strengthened) products are also listed.

This article describes the influence of steel chemical compositions and microstructure on machining processes. It discusses the various microstructural phases of standard carbon and alloy steels, which influence machinability. The article reviews the expected response of several traditional machining operations, such as turning, drilling, milling, shaping, thread cutting, and grinding, to the microstructure of standard steel grades. It also explains the technologies in non-traditional machining processes, such as abrasive waterjet cutting, electrical chemical grinding, and laser drilling.

This article discusses the different classes of gears, namely, spur, helical, herringbone, crossed-axes helical, worm, internal, rack, bevel, or face-type. It describes the methods used to cut the teeth of gears other than bevel gears: milling, broaching, shear cutting, hobbing, shaping, and rack cutting. The article also reviews the methods that are used to cut the teeth of bevel gears, such as face mill cutting, face hob cutting, formate cutting, helix form cutting, the Cyclex method, and template machining. The machining methods best suited to specific conditions are discussed. The article presents the factors influencing the choice of cutting speed and cutting fluids. It outlines two basic methods for the grinding of gear teeth: form grinding and generation grinding. The article concludes with information on the gear inspection techniques used to determine whether the resulting product meets design specifications and requirements.

This article begins with a discussion on the classification of aluminum alloys and the selection of alloy and temper based on machinability. It provides an overview of cutting force and power, tool design and material, and general machining conditions. In addition, the article discusses distortion and dimensional variation and machining problems during the machining of high-silicon aluminum alloy. It also provides information on tool design and material, speed and feed, and the cutting fluid used for various machining processes, namely, turning, boring, planing and shaping, broaching, reaming, tapping, milling, sawing, grinding, honing, and lapping. The article concludes with a discussion on drilling operations in automatic bar and chucking machines and drill presses.

This article begins with a discussion on machinability ratings of copper and copper alloys and then describes the factors influencing the machinability ratings. It explains the effect of alloying elements, cold working, and cutting fluid on the machinability of copper and copper alloys. In addition, the article provides a comprehensive discussion on various machining techniques that are employed for machining of copper and copper alloys: turning, planing, drilling, reaming, tapping and threading, multiple operation machining, milling, slitting and circular sawing, power band sawing and power hacksawing, grinding, and honing.