Machine tool is a machine for forming or processing metal or other rigid materials, usually by cutting, drilling, grinding, cutting, or other deformation forms. Machine tools use a kind of tool that performs cutting or forming. All machine tools have several means to limit the workpiece and provide guided movement of the engine parts. So the relative motion between workpiece and cutting tool (called toolpath ) is controlled or limited by the machine to at least some level, rather than completely "just" or "free".
The exact definition of machine tools terms varies among users, as discussed below. While all machine tools are "machines that help people to make things", not all factory machines are machine tools.
Currently, machine tools are usually supported in addition to human muscles (eg, electrically, hydraulically, or through the channel shaft), used to make artificial components in various ways that include cutting or certain types of deformations.
With inherent precision, machine tools enable the economical production of interchangeable parts.
Video Machine tool
Many tech historians assume that the correct machine tool was born when the chisel trajectory was first guided by the machine itself in some way, at least to some extent, so direct, direct man's direction from the chisel path (by hand, foot or mouth) was no longer one only guidance used in the process of cutting or forming. In this view the definition, the term, which arises when all instruments up to that point are hand tools, is simply labeled for "tools that are machines not hand tools". The earliest lathes, which were before the late medieval period, and lathe lathe and pottery machines may or may not be included in this definition, depending on how one looks at the headstock itself; but the earliest historical record of a lathe with direct mechanical control of the cutting lane is a cutting-edge machine dating from about 1483. This lathe "produces a threaded screw from wood and uses the correct compound. rest ".
Guide waveguide mechanical tools grow from a variety of basic concepts:
- First is the concept of spindle itself, which restricts movement of workpiece or tool to rotate around the fixed axis. This ancient concept precedes machine tools per se; early lathes and pottery wheels are combined for the workpiece, but the movement of the tool itself on this machine is completely free.
- Slide machine, which has many shapes, such as how to fit, how to box, or how to column cylinders. Slides machines limit the tool or movement of the workpiece in a linear manner. If the stop is added, the length of the line can also be controlled accurately. (Machine slides are basically part of linear bearing, although the languages ​​used to classify the various elements of this machine include connotative limits; some users in some contexts will contradict elements in ways others may not.)
- Tracing, which involves following a model or template contour and transferring the resulting motion to the chisel path.
- Camera operation, which is linked principally to search but can be one or two deleted steps from a traceable element that matches the final shape of the reproduced element. For example, some cams, none of which directly match the desired output form, can move complex path tools by creating component vectors added to the net tool path.
- Van Der Waals Style Between metal as high; the manufacture of free goods as described below in the History of square plates produces only square, flat, accurate machine tools up to a millionth of an inch, but there is almost no variation. The feature replication process allows the flatness and quadraticity of the milling machine or roundness, the lack of taper, and the squares of the two axis lathes to be transferred to the machine workpiece with accuracy and precision better than a thousandth of an inch, not as good as a millionth of an inch. Since the suitability of the shear component of a manufactured product, machine, or machine tool approximates a thousandth of an inch measurement, this lubricity and capillary action combine to prevent Van Der Walls forces from welding like metals together, extending the life of parts welded by a factor thousands to millions; oil depletion disasters in conventional automotive engines are demonstrable needs that can be accessed, and in aerospace design, the design is similar-to-not used along with solid lubricants to prevent Van Der Walls welding from destroying the mating surface.
An abstractly programmed toolpath guide starts with a mechanical solution, such as in a camera box and a Jacquard loom. Convergence of programmable mechanical controls with machine tool tool controls has been delayed for decades, in part because the controlled method of music boxes and looms has no rigidity for machine tools. Then, electromechanical solutions (such as servos) and immediate electronic solutions (including computers) are added, leading to numerical controls and numerical control of computers.
When considering the difference between a hand-free toolpath and a machine-limited toolpath, the concept of accuracy and precision, efficiency, and productivity are important in understanding why the restricted options add value.
Material-Additive, Matter-Preserving, and Matter-Subtractive "Manufacturing" can be continued in 16 ways: Work can be held in hand or clamp; tool can be held by hand (other hand) or clamp; power may come from hands holding appliances and/or work, or from some external source, including stamping by the same worker, or motor without restriction; and control can come from hands that hold the tools and/or work, or from several other sources, including computer numerical controls. With two options for each of the four parameters, they are mentioned in sixteen types of Manufacturing, where Materials-Additives may mean painting on canvas as easy as it may mean 3D printing under computer control, Maintenance-Matter may mean forging in a coal fire as ready as a plate stamping plate, and Matter-Subtracting might mean shrink the pencil point easily as it might mean precision grinding the final shape of a stored laser turbine blade.
Humans are generally quite gifted in their free-hand movements; drawings, paintings, and sculptures of artists such as Michelangelo or Leonardo da Vinci, and countless other talented people, indicate that the free hand-held tool path has great potential. The value of machine tools added to the human talent is in the area of ​​rigidity (inhibiting the chisel path though there are thousands of newtons (pounds) of power struggling against the constraints), accuracy and precision, efficiency, and productivity. With machine tools, the chisel trajectories that can not be restricted by human muscles can be restricted; and toolpaths that are technically possible with hands-free methods, but will require tremendous time and skill to execute, whereas it can be executed quickly and easily, even by people with little free-handed talent (because of the machine that takes care of it). The final aspect of machine tools is often referred to by technology historians as "building skills into the tool", in contrast to the toolpath-constraining skill residing in the person using the tool. For example, it is physically possible to make interchangeable screws, bolts and nuts completely with hand-free tool paths. But economical is practical to make it only with machine tools.
In the 1930s, the US National Economic Research Bureau (NBER) refers to the definition of machine tools as "any machine operating apart from the power of a hand using tools to work on metal".
The narrowest meaning of the language of the reserve term is only for machines that cut metal - in other words, many types of machining and grinding [conventional]. These processes are a type of deformation that produces swarf. However, economists use a slightly broader understanding that also includes the deformation of other metals that suppress metals to form without cutting swarves, such as rolling, stamping with dies, shearing, swaging, riveting, and others. So pressure is usually included in the machine tool's economic definition. For example, this is the breadth of the definition used by Max Holland in the history of Burgmaster and Houdaille, which is also the history of the general machine-tool industry from the 1940s to the 1980s; he reflects the meaning of the terms used by Houdaille himself and other companies in the industry. Many reports on the export and import of machine tools and similar economic topics use this broader definition.
The everyday sense that implies conventional metal cutting is also increasingly obsolete due to technological changes for decades. Many recently developed processes that are labeled "machining", such as electric displacement machining, electrochemical machining, electron beam filming, photochemical machining, and ultrasonic machining, or even plasma cutting and water jet cutting are often performed by machines that can be logical to be called a machine tool. In addition, some newly developed additive manufacturing processes, which are not about cutting materials but more about adding them, are done by machines that tend to end up labeled, in some cases, as machine tools. In fact, machine tool makers have developed machines that include making subtractive and additives in one work envelope, and retrofits of existing machines are being done.
The use of natural language of the term varies, with smooth connotative borders. Many speakers refuse to use the term "machine tool" to refer to woodworking machines (joiners, table saws, routing stations, etc.), but it is difficult to maintain the correct logical barrier line, and therefore many speakers accept a broad definition. It is common to hear engineers refer to their machine tools as simply "machines". Usually the mass noun "machine" covers them, but is sometimes used to imply only machines that are excluded from the definition of "machine tool". This is why machines in food processing plants, such as conveyors, mixers, boats, splitters, and so on, can be labeled "machines", while machines in tool plants and die departments are called "machine tools" in contradiction. As for the NBER definition of the 1930s quoted above, one can argue that its specificity to metal is obsolete, as it is quite common today for special lathe, milling machines, and machining centers (exact machine tools) to work exclusively on work cutting plastic throughout their entire lifetime of work. Thus the above NBER definition can be extended to say "using tools to work on metals or other materials of high violence ". And the specificity to "operate with other than hand strength" is also problematic, because machine tools can be supported by people if properly arranged, such as with pedals (for lathes) or hand levers (for shapers). The hand-powered formers are clearly "the same thing" as molders with electric motors except the smaller ones ", and it's trivial for the power of a micro lathe with a hand-turning pulley pulley instead of an electric motor. Thus one can question whether resources are really the main distinguishing concept; but for economic purposes, the NBER definition makes sense, since most commercial values ​​of the existence of machine tools come through that of electric power, hydraulics, and so on. Such are the twists and turns of the natural language and controlled vocabulary, both of which have a place in the business world.
Maps Machine tool
History
The pioneer of machine tools including arch exercises and pottery wheels, which had existed in ancient Egypt before 2500 BC, and lathe, are known to have existed in some parts of Europe from at least 1000 to 500 BC. But it was only in the Middle Ages and the Age of Enlightenment that the modern concept of machine tool - the machine class used as a tool in the manufacture of metal parts, and incorporating machine - guided tools - began to flourish. Medieval clockmakers and renaissance men like Leonardo da Vinci help extend the environment of human technology to the preconditions for industrial machinery equipment. During the 18th and 19th centuries, and even in many cases in the 20th century, machine tool builders tend to be the same people who would then use them to produce the final product (manufactured goods). However, from these roots is also evolving machine tool making industry as we defined today, which means people who specialize in building machine tools to sell to others.
Historians of machine tools often focus on some of the major industries that most encourage the development of machine tools. In the order of historical occurrences, they are firearms (small arms and artillery); hour; textile machinery; steam engines (stationary, marine, railways, and others) (stories of how Watt's need for accurate cylinders spur the boring machine of Boulton discussed by Roe); sewing machine; bike; car; and airplanes. Other people can be included in this list as well, but they tend to connect with the root cause already registered. For example, rolling element bearings are the industry itself, but the industry's key drivers are already registered vehicles - trains, bicycles, cars and airplanes; and other industries, such as tractors, farm equipment, and tanks, borrowing many from the same parent industry.
Machine tools meet the needs made by textile machinery during the Industrial Revolution in England in the mid to late 1700s. Until then machines were made mostly of wood, often including gearing and shaft. Increased mechanization requires more metal parts, which are usually made of cast iron or wrought iron. Cast iron can be cast in a mold for larger parts, such as engine cylinders and gears, but difficult to work with files and can not be hammered. Hot red wrought iron can be hammered into shape. Wrought iron room temperature is done with files and chisels and can be made into gears and other complex parts; However, working hands are less precise and are a slow and expensive process.
James Watt could not have an accurate cylinder for his first steam engine, attempting for several years until John Wilkinson invented a suitable boring machine in 1774, Boulton & amp; Watt's first commercial engine in 1776.
Progress in machine tool accuracy can be traced to Henry Maudslay and perfected by Joseph Whitworth. Maudslay has established the making and use of master plane gages in his shop (Maudslay & Field) located on Westminster Road south of the Thames River in London around 1809, evidenced by James Nasmyth employed by Maudslay in 1829 and Nasmyth documenting his use in his autobiography.
The process by which the aircraft gages are manufactured back in time but is refined to an unprecedented level in the Maudslay store. The process starts with three square plates each given identification (for example, 1,2 and 3). The first step is to scrub the plates 1 and 2 together with the marking medium (called bluing today) which reveals the high points to be removed by scratching the hand with the steel scraper until no deviation is seen. This will not produce the correct plane surface but concave and concave, since this mechanical fit, like two perfect planes, can shift to one another and show no high points. Rubbing and marking is repeated after turning 2 relative to 1 by 90 degrees to remove the curvature of the concave "potato-chip". Furthermore, the large number 3 plates (the process is still used) are compared and dredged to fit the number 1 plate in the same two experiments. In this way plate number 2 and 3 will be the same. The next plates of numbers 2 and 3 will be checked for each other to determine what conditions exist, whether the plates are "spheres" or "sockets" or "chips" or combinations. This will then be scraped until there are no high spots and then compared with plate number 1. Repeating the process of comparing and scratching these three plates can produce an accurate field surface of up to a million inches (the thickness of the marking medium).
Traditional methods produce surface gages using coarse powder rubbed between plates to remove high spots, but it is Whitworth that contributes to the repair replacing grinding with hand friction. Sometime after 1825 Whitworth went to work for Maudslay and that was where Whitworth perfected the aircraft carrier's friction. In his paper presented to the British Association for the Advancement of Science in Glasgow in 1840, Whitworth demonstrated the inherent inherent in grinding because there is no uneven control and distribution of abrasive materials between the plates which would result in the removal of uneven material from the plate.
With the creation of master plane gages with high accuracy, all important components of machine tools (ie, guiding surfaces like machine way) can then be compared with them and scraped into desired accuracy. The first machine tools offered for sale (ie, commercially available) were built by Matthew Murray in the UK around 1800. Others, such as Henry Maudslay, James Nasmyth, and Joseph Whitworth, soon followed the path of expanding their entrepreneurship from the final product produced and millwright work in the field of building machine equipment for sale.
Important machine tools include sliding lathes, cutting machines, turret lathe, milling machines, pattern lathes, molders and planer metals, all of which were used before 1840. With these machine tools the purpose of aging decades to produce replaceable parts was finally realized. An important initial example of something that is now considered normal is the standardization of screw fasteners such as nuts and bolts. Before about the beginning of the 19th century, these were used in pairs, and even screws of the same machine were generally not interchangeable. The method was developed to cut the screw thread to a higher precision than the feed screws in the lathe used. This led to a long bar standard from the late 19th and early 20th century.
The production of American machine tools was an important factor in Allied victories in World War II. Machine tool production tripled in the United States in the war. There is no more advanced war than World War II, and it has been written that wars were won by machine shops like by machine guns.
Machine tool production is concentrated in around 10 countries around the world: China, Japan, Germany, Italy, South Korea, Taiwan, Switzerland, USA, Austria, Spain, and others. Machine tool innovation continues in several public and private research centers around the world.
Drive resources
"All the iron turns for a cotton machine built by Mr. Slater are done with a chisel of hand or tool in a crank-driven lathes with hand strength." David Wilkinson
Machine tools can be empowered from multiple sources. Humans and animals (through cranks, treadles, treadmills, or treadwheels) were used in the past, such as the strength of water (through the water wheel); However, following the development of high-pressure steam engines in the mid-19th century, more and more plants use steam power. The plant also uses hydraulic and pneumatic power. Many small workshops continue to use water, human and animal power until electrification after 1900.
Currently most of the machine equipment is powered by electricity; However, hydraulic and pneumatic power is sometimes used, but this is not common.
Automatic control
Machine tools can be operated manually, or under automatic control. Initial engines use flywheels to stabilize their movements and have an elaborate gear and lever system to control the machines and pieces that are being worked on. Immediately after World War II, numerical control machines (NC) were developed. The NC machine uses a series of numbers perforated on paper tape or perforated cards to control their movements. In the 1960s, computers were added to provide more flexibility for the process. Such machines are known as computerized numerical control machines (CNCs). NC and CNC machines can precisely repeat the sequence over and over again, and can produce much more complicated pieces than even the most expert tool operators.
Shortly, the machine can automatically change the cutting tool and establish the specific being used. For example, a drill machine may contain a magazine with various drill bit to produce holes of various sizes. Previously, machine operators typically had to manually change little or move the workpiece to another station to perform this different operation. The next logical step is to combine several different machine tools together, all under the control of the computer. It's known as a machining center, and has dramatically changed the way parts are made.
Example
Examples of machine tools are:
- Processing machine
- Drill press
- Toothbrush
- The hobbing machine
- Hone
- Lathe
- Screw machine
- Milling machine
- Slide (sheet metal)
- Shaper
- Chainsaw
- Planer
- Stewart's platform milling
- Grinding machine
- Multitasking machines (MTMs) - a multilevel CNC machine tool that combines turning, milling, grinding, and material handling into a highly automated machine tool
When creating or forming parts, several techniques are used to remove unwanted metals. Among others are:
- Electrical discharge machining
- Milling (rough cut)
- Double edge cutting tool
- Single edge cutting tool
Another technique is used to add the desired material. Devices that make components with selected enhancement materials are called fast prototyping machines.
Machine tool manufacturing industry
. Biogas machine tool makers that also contain some general industrial histories.
- Rolt, L.T.C. (1965), Short History Machine Tool , Cambridge, Massachusetts, USA: MIT Press, OCLCÃ, 250074 Ã, . Co-edition published as Rolt, L.T.C. (1965), Tools for Work: Short History Machine Tool , London: BT Batsford, LCCNÃ, 65080822 Ã, . (edit)
- Ryder, Thomas and Son, Machine Engraving 1865 to 1968 , a centenary book, (Derby: Bemrose & Sons, 1968) Woodbury, Robert S. (1972), Machine Tool History , Cambridge, Massachusetts, USA, and London, England: MIT Press, ISBNÃ, 978-0-262-73033-4, LCCNÃ, 72006354 title Ã, . The previously published monograph collection is tied up as a single volume. The classic collection of seminal from the history of machine tools.
External links
Source of the article : Wikipedia
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