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.

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.

Nickel-base alloys can be machined by techniques that are used for iron-base alloys. This article discusses the effects of distortion and microstructure on the machinability of nickel alloys. It tabulates the classification of nickel alloys based on machining characteristics. The article describes the machining operations performed on nickel alloys, such as turning, planing and shaping, broaching, reaming, drilling, tapping and threading, milling, sawing, and grinding. It provides information on the cutting fluids used in the machining of nickel alloys. The article also analyzes nontraditional machining methods that are suitable for shaping high-temperature, high-strength nickel alloys. These include electrochemical machining, electron beam machining, and laser beam machining.

In-process tool monitoring systems can electronically detect excessive tool wear or warn of impending tool failure to lessen machine downtime and prevent the production of out-of-tolerance parts. This article discusses the sensing technology available for manufacturing applications, as wells as the advantages and disadvantages of this technology. It describes the roles of the three basic elements to any modern sensing system: sensing source, signal amplifier, and microprocessor or translator. The article reviews two case studies from two different ends of the metal removal spectrum, broaching and drilling, to emphasize the cost effectiveness of using a tool condition monitoring system.

The machinability of stainless steels varies from low to very high, depending on the final choice of the alloy. This article discusses general material and machining characteristics of stainless steel. It briefly describes the classes of stainless steel, such as ferritic, martensitic, austenitic, duplex, and precipitation-hardenable alloys. The article examines the role of additives, such as sulfur, selenium, tellurium, lead, bismuth, and certain oxides, in improving machining performance. It provides ways to minimize difficulties involved in the traditional machining of stainless steels. The article describes turning, drilling, tapping, milling, broaching, reaming, and grinding operations on stainless steel. It concludes with information on some of the nontraditional machining techniques, including abrasive jet machining, abrasive waterjet machining electrochemical machining, electron beam machining, and plasma arc machining.

This article discusses the fundamentals of broaching, including broach tooth terminology, broach cutting action, and broach size. It describes two types of broaching machines: horizontal and vertical. The article illustrates three general categories of broaches: solid, shell, and insert-type. It tabulates feeds and speeds for broaching various steels with high-speed tool steels and carbide tools. The article also describes the advantages and limitations of broaching and provides a brief discussion on burnishing. The causes and prevention of broach breakage are also discussed. The article concludes with information on broach repair.

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.

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 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 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.

Magnesium is machined in low-volume production on small, manually operated machine tools and on large, specially built, completely automated transfer machines operating at high production rates. This article focuses on the factors that affect the machining of magnesium. It discusses chip formation and distortion due to thermal expansion, cold work, and clamping and provides information on magnesium-matrix composites. The article describes materials, design, and sharpness as factors for selection of tool for machining magnesium. It illustrates turning and boring, planing and shaping, broaching, drilling, reaming, counterboring, milling, sawing, and grinding operations performed on magnesium. Safety measures related to machining, handling of chips and fines, and fire extinguishing are also discussed.