Machining is one of the most important of the basic manufacturing processes. Almost every manufactured product contains components that require machining, often to great precision. Yet material removal operations are among the most expensive; in the U.S. alone, more than $100 billion will be spent this year on machining. These high costs put tremendous economic pressures on production managers and engineers as they struggle to find ways to increase productivity. Compounding their problems is the increasing use of more difficult-to-machine materials, such as nickel-base superalloys and titanium-base alloys in aerospace applications, structural ceramics, high-strength polymers, composites (both metal-matrix and resin-matrix), and electronic materials.
The present Volume of Metals Handbook has been structured to provide answers to the questions and challenges associated with current machining technology. Following a general introduction to machining processes, 9 major sections containing 78 articles cover all aspects of material removal. Much of this material is new. In fact, 30 articles in this Volume were not included in its 8th Edition predecessor. Noteworthy are the articles that have been added to describe the mechanics of the cutting process and advances in new materials, new processes, new methods of machine control, and computer-aided engineering.
The first Section of the Handbook reviews the fundamentals of the machining process. Included are articles describing the mechanics of chip formation, the forces, stresses, and power at the cutting tool, the principles of tool wear and tool life, and the relationship between cutting and grinding parameters and surface finish and surface integrity.
In the following Section, extensive data are provided on the applications, advantages and limitations, properties, tool geometries, and typical operating parameters for seven classes of tool materials: high-speed tool steels (both conventional wrought and powder metallurgy), cast cobalt alloys, cemented carbides, cermets, ceramics, and ultrahard tool materials (polycrystalline diamond and cubic boron nitride). Recent developments in wear-resistant coatings that are applied on high-speed steel, carbides, and ceramics are also discussed.
The third Section focuses on cutting and grinding fluids—their functions, selection criteria, and application. Coverage of proper maintenance procedures (storage, handling, recycling, and disposal) and the toxicology and biology associated with cutting and grinding fluids is included.
The next Section contains 21 articles that summarize the process capabilities, machines, cutting parameters and variables, and applications of traditional chip removal processes, such as turning, drilling, and milling. Advanced tooling used in multiple-operation machining, proper tool fixturing, and tool condition monitoring systems are also discussed, along with computer numerical controlled machining centers, flexible manufacturing systems, and transfer machines.
Although near net shape technology, including a greater use of precision casting, powder metallurgy, and precision forging, has lessened the need for some traditional machining operations, abrasive machining is being employed to a greater extent than in the past. The fifth Section of the Handbook examines the principles, equipment, and applications of grinding, honing, and lapping as well as recent developments in super-abrasives, used for precision grinding of difficult-to-machine and/or brittle materials.
The sixth Section looks at a variety of nontraditional machining methods that do not produce chips or a lay pattern in the surface. Mechanical, electrical, thermal, and chemical nontraditional techniques are described. Applications of these methods are emphasized, with practical examples involving nontraditional machining of metals, ceramics, glasses, plastics, and electronic components.
The next Section describes high-speed and high removal rate processes that have been developed to dramatically increase productivity. The effects of high-speed processing on chip formation and tool wear are discussed, along with materials that are being machined using these processes.
The eighth Section introduces the reader to two of the most rapidly developing and important areas in machining technology: machine controls and computer applications. Although the basic configurations of many machine tools have not changed significantly, the advent of numerical control and adaptive control has substantially improved manufacturing productivity and workpiece quality. Machine controls and the integration of CAD/CAM technology into machine tools are described in articles written with the engineer, not the software expert, in mind.
The last Section of the Handbook covers specific machining practices for 23 different metal systems, including all structural alloy systems, and relates the latest information on such topics as powder metals, metal-matrix composites, and honeycomb structures. Machining parameters (speeds, feeds, depth-of-cut, etc.) and the influence of microstructure on machinability are described in detail. Coverage includes difficult-to-machine aerospace alloys and high-silicon cast aluminum alloys, as well as materials such as beryllium and uranium that require special considerations during machining. Finally, an article on machinability test methods examines various types of tests used to study cutting tool and workpiece machining characteristics.
Much of the credit for the content and organization of this Handbook must be given to the Steering Committee that worked with the ASM staff during the early stages of the project. This group includes Professor George E. Kane, Lehigh University; Dr. William P. Koster, Metcut Research Associates Inc.; Dr. Ranga Komanduri, National Science Foundation; Dr. Richard P. Lindsay, Norton Company; Mr. Gary F. Benedict, Allied-Signal Aerospace Company, Garrett Engine Division; and Mr. Michael E. Finn, Stelco Inc. We are also indebted to the officers of the Society of Carbide and Tool Engineers for their assistance in the planning of the Volume. Finally, we gratefully acknowledge the countless hours of time and expertise loaned to the project by the nearly 200 authors and reviewers. Without the collective efforts of all these individuals, the successful completion of this Handbook would not have been possible.