A machine tool is a powered mechanical device, typically used to fabricate metal components of machines by machining Conventional machining, one of the most important material removal methods, is a collection of material-working processes in which power-driven machine tools, such as lathes, milling machines, and drill presses, are used with a sharp cutting tool to mechanically cut the material to achieve the desired geometry. Machining is a part of the, which is the selective removal of metal. The term machine tool is usually reserved for tools that used a power source other than human movement, but they can be powered by people if appropriately set up. Many historians of technology consider that the true machine tools were born when direct human involvement was removed from the shaping or stamping process of the different kinds of tools. The earliest lathe with direct mechanical control of the cutting tool was a screw-cutting lathe dating to about 1483.[1] This lathe "produced screw threads out of wood and employed a true compound slide rest".
The first machine tools offered for sale (i.e. commercially available) were constructed by one Matthew Murray in England around 1800.[2]
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Overview
Machine tools can be powered from a variety of sources. Human and animal power are options, as is energy captured through the use of waterwheels A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. the development of hydropower. In the Middle Ages, waterwheels were used as tools to power factories throughout different countries. The alternatives were the windmill and human and animal power. The most common use of the water wheel. However, modern machine tools began to develop only after the development of the steam engine A steam engine is a heat engine that performs mechanical work using steam as its working fluid, which led to the Industrial Revolution The Industrial Revolution was a period from the 18th to the 19th century where major changes in agriculture, manufacturing, mining, transport and technology had a profound effect on the socioeconomic and cultural conditions starting in the United Kingdom, then subsequently spreading throughout Europe, North America, and eventually the world. The. Today, most machine tools are powered by electricity.
Machine tools can be operated manually, or under automatic control. Early machines used flywheels A flywheel is a mechanical device with a significant moment of inertia used as a storage device for rotational energy. Flywheels resist changes in their rotational speed, which helps steady the rotation of the shaft when a fluctuating torque is exerted on it by its power source such as a piston-based engine, or when an intermittent load, such as a to stabilize their motion and had complex systems of gears and levers to control the machine and the piece being worked on. Soon after World War II, the numerical control Numerical control refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via handwheels or levers, or mechanically automated via cams alone. The first NC machines were built in the 1940s and '50s, based on existing tools that were modified with (NC) machine was developed. NC machines used a series of numbers punched on paper tape Punched tape or paper tape is a largely obsolete form of data storage, consisting of a long strip of paper in which holes are punched to store data. It was widely used during much of the twentieth century for teleprinter communication, and later as a storage medium for minicomputers and CNC machine tools or punched cards A punched card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions. Now almost an obsolete recording medium, punched cards were widely used throughout the 19th century for controlling textile looms and in the late 19th and early 20th century for operating fairground to control their motion. In the 1960s, computers were added to give even more flexibility to the process. Such machines became known as computerized numerical control (CNC) machines. NC and CNC machines could precisely repeat sequences over and over, and could produce much more complex pieces than even the most skilled tool operators.
Before long, the machines could automatically change the specific cutting and shaping tools that were being used. For example, a drill A drill or drill motor is a tool fitted with a rotating cutting tool, usually a drill bit, used for drilling holes in various materials. The cutting tool is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip of the cutting tool does the work of cutting into the target material. This may be machine might contain a magazine with a variety of drill bits Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes for producing holes of various sizes. Previously, either machine operators would usually have to manually change the bit or move the work piece to another station to perform these different operations. The next logical step was to combine several different machine tools together, all under computer control. These are known as machining centers A milling machine is a machine tool used to machine solid materials. Milling machines are often classed in two basic forms, horizontal and vertical, which refers to the orientation of the main spindle. Both types range in size from small, bench-mounted devices to room-sized machines. Unlike a drill press, which holds the workpiece stationary as, and have dramatically changed the way parts are made.
From the simplest to the most complex, most machine tools are capable of at least partial self-replication Self-replication is any process by which a thing will make a copy of itself. Biological cells, given suitable environments, reproduce by cell division. During cell division, DNA is replicated and can be transmitted to offspring during reproduction. Biological viruses can reproduce, but only by commandeering the reproductive machinery of cells, and produce machine parts as their primary function.
Examples
Examples of machine tools are:
- Broaching machine Broaching is a machining operation which uses a toothed tool, called a broach, to remove material. The broach is used in a broaching machine, which is also sometimes shortened to broach. It is used when precision machining is required, especially for odd shapes. Broaching finishes a surface in a single pass, which makes it very efficient. Commonly
- Drill press A drill or drill motor is a tool fitted with a rotating cutting tool, usually a drill bit, used for drilling holes in various materials. The cutting tool is gripped by a chuck at one end of the drill and rotated while pressed against the target material. The tip of the cutting tool does the work of cutting into the target material. This may be
- Gear shaper A gear shaper is a machine tool for cutting the teeth of internal or external gears. The name shaper relates to the fact that the cutter engages the part on the forward stroke and pulls away from the part on the return stroke, just like the clapper box on a planer shaper. To cut external teeth, a different machine called a hobbing machine can be
- Hobbing machine A hobbing machine is a special form of milling machine that cuts gears. It is the major industrial process for cutting spur gears of involute form
- Hone Honing is an abrasive machining process that produces a precision surface on a metal workpiece by scrubbing an abrasive stone against it along a controlled path. Honing is primarily used to improve the geometric form of a surface, but may also improve the surface texture
- Lathe A lathe is a machine tool which spins a block of material to perform various operations such as cutting, sanding, knurling, drilling, or deformation with tools that are applied to the workpiece to create an object which has symmetry about an axis of rotation
- Screw machines
- Milling machine A milling machine is a machine tool used to machine solid materials. Milling machines exist in two basic forms: horizontal and vertical, which terms refer to the orientation of the cutting tool spindle. Unlike a drill press, in which the workpiece is held stationary and the drill is moved vertically to penetrate the material, milling also involves
- Shaper A shaper is a type of machine tool that uses linear relative motion between the workpiece and a single-point cutting tool to machine a linear toolpath. Its cut is analogous to that of a lathe, except that it is linear instead of helical. A shaper is analogous to a planer, but smaller, and with the cutter riding a ram that moves above a stationary
- Saws A saw is a tool that uses a hard blade or wire with an abrasive edge to cut through softer materials. The cutting edge of a saw is either a serrated blade or an abrasive. A saw may be worked by hand, or powered by steam, water, electricity or other power
- Planer A planer is a type of metalworking machine tool that is analogous to a shaper, but larger, and with the entire workpiece moving beneath the cutter, instead of the cutter moving above a stationary workpiece. The work table is moved back and forth on the bed beneath the cutting head either by mechanical means, such as a rack and pinion gear, or by a
- Stewart platform mills
- Grinding machines A grinding machine is a machine tool used for grinding, which is a type of machining using an abrasive wheel as the cutting tool. Each grain of abrasive on the wheel's surface cuts a small chip from the workpiece via shear deformation
When fabricating or shaping parts, several techniques are used to remove unwanted metal. Among these are:
- Electrical discharge machining Electric discharge machining , sometimes colloquially also referred to as spark machining, spark eroding, burning, die sinking or wire erosion, is a manufacturing process whereby a wanted shape of an object, called workpiece, is obtained using electrical discharges (sparks). The material removal from the workpiece occurs by a series of rapidly
- Grinding (abrasive cutting) Grinding is a machining process that uses an abrasive wheel as the cutting tool
- Multiple edge cutting tools
- Single edge cutting tools
Other techniques are used to add desired material. Devices that fabricate components by selective addition of material are called rapid prototyping Rapid prototyping is the automatic construction of physical objects using additive manufacturing technology. The first techniques for rapid prototyping became available in the late 1980s and were used to produce models and prototype parts. Today, they are used for a much wider range of applications and are even used to manufacture production- machines.
Several regions of the United States became centers for machine tool development between 1800 and 1950, including Philadelphia, Pennsylvania; Cincinnati, Ohio; Rockford, Illinois; Providence, Rhode Island] Springfield, Vermont; Windsor, Vermont; Hartford, Connecticut; and Bridgeport, Connecticut.
See also
- Category:Machine tool builders
- Epoxy granite
- Four slide machine
- Self-replicating machine A self-replicating machine is an artificial construct that is theoretically capable of autonomously manufacturing a copy of itself using raw materials taken from its environment. The concept of self-replicating machines has been advanced and examined by Homer Jacobsen, Edward F. Moore, Freeman Dyson, John von Neumann and in more recent times by K
- Machining vibrations
- Machinist calculator
- Metalworking Metalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewellery. It therefore includes a correspondingly wide range of skills, processes, and tools
- Multimachine - an open source machine tool
- Swarf Swarf, also known as turnings, chips, or filings, are shavings and chippings of metal — the debris or waste resulting from metalworking operations. It can usually be recycled, and this is the preferred method of disposal due to the environmental concerns regarding potential contamination with cutting fluid or tramp oil. The ideal way to remove
- Tool bit The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, shapers, and planers. Such cutters are also often referred to by the set-phrase name of single-point cutting tool. The cutting edge is ground to suit a particular machining operation and may be resharpened or reshaped as needed. The ground tool bit is held
- Tool wear Tool wear describes the gradual failure of cutting tools due to regular operation. It is a term often associated with tipped tools, tool bits, or drill bits that are used with machine tools
References
Bibliography
- Moore, Wayne R. (1970), Foundations of Mechanical Accuracy (1st ed.), Bridgeport, CT, USA: Moore Special Tool Co., LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 73-127307 .
Further reading
History of machine tools
- Floud, Roderick C. (2006) [1976], The British Machine Tool Industry, 1850-1914, Cambridge, England: Cambridge University Press, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 2006-275684, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 75-046133, ISBN 0521212030, ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 978-0521025553, http://www.worldcat.org/oclc/70251252 .
- Hounshell, David A. David A. Hounshell is the David M. Roderick Professor of Technology and Social Change in the Department of Social and Decision Sciences, Department of History, and the Department of Engineering and Public Policy at Carnegie Mellon University (1984), From the American system to mass production, 1800-1932: The development of manufacturing technology in the United States, Baltimore, Maryland, USA: Johns Hopkins University Press, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 83-016269, ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 978-0-8018-2975-8 .
- Noble, David F. David Franklin Noble is a critical historian of technology, science and education. He is best known for his seminal work on the social history of automation. He currently teaches in the Division of Social Science, and the department of Social and Political Thought at York University in Toronto, Canada (1984), Forces of production: a social history of industrial automation, New York: Knopf, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 83-048867, ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 978-0-394-51262-4 .
- Roe, Joseph Wickham (1916), English and American Tool Builders, New Haven, Connecticut, USA: Yale University Press, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 16-011753, http://books.google.com/books?id=X-EJAAAAIAAJ&printsec=titlepage . Reprinted by McGraw-Hill, New York and London, 1926 (LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 27-024075); and by Lindsay Publications, Inc., Bradley, IL, USA (ISBN 978-0-917914-73-7).
- Rolt, L.T.C. Lionel Thomas Caswall Rolt (11 February 1910 – 9 May 1974) was a prolific English writer and the biographer of major civil engineering figures including Isambard Kingdom Brunel and Thomas Telford. He is also regarded as one of the pioneers of the leisure cruising industry on Britain's inland waterways, and as an enthusiast for both vintage cars (1965), A Short History of Machine Tools, Cambridge, Massachusetts, USA: MIT Press, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 65-12439 . Co-edition published as Rolt, L.T.C. (1965), Tools for the Job: a Short History of Machine Tools, London: B. T. Batsford, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 65-080822 .
- Woodbury, Robert S. (1972), Studies in the History of Machine Tools, Cambridge, Massachusetts, USA, and London, England: MIT Press, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 72-006354, ISBN The International Standard Book Number is a unique numeric commercial book identifier based upon the 9-digit Standard Book Numbering (SBN) code created by Gordon Foster, now Emeritus Professor of Statistics at Trinity College, Dublin, for the booksellers and stationers W.H. Smith and others in 1966 978-0-262-73033-4 . Collection of previously published monographs bound as one volume.
Machine shop practice
- Moltrecht, Karl Hans (1981), Machine Shop Practice (2 vols) (2nd ed.), New York: Industrial Press Industrial Press, Inc., is a privately held corporation headquartered in New York City. Its primary areas of business are publishing technical books for engineering, technology, and manufacturing, LCCN The Library of Congress Control Number or LCCN is a serially based system of numbering cataloging records in the Library of Congress in the United States. It has nothing to do with the contents of any book, and should not be confused with Library of Congress Classification 79-091236, ISBN 978-0831111267 .
- Rose, Joshua (1887), Modern Machine-Shop Practice (2 vols) (1 ed.), New York: Charles Scribner's Sons, LCCN 06-032714, http://catalog.lib.msu.edu/record=b6808254~S39a .
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