Mechanization

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A water-powered mine hoist used for raising ore. This woodblock is from De re metallica by George Bauer (pen name Georgius Agricola, ca. 1555) an early mining textbook that contains numerous drawings and descriptions of mining equipment. Agricola1.jpg
A water-powered mine hoist used for raising ore. This woodblock is from De re metallica by George Bauer (pen name Georgius Agricola, ca. 1555) an early mining textbook that contains numerous drawings and descriptions of mining equipment.

Mechanization (or mechanisation) is the process of changing from working largely or exclusively by hand or with animals to doing that work with machinery. In an early engineering text, a machine is defined as follows:

Contents

Every machine is constructed for the purpose of performing certain mechanical operations, each of which supposes the existence of two other things besides the machine in question, namely, a moving power, and an object subject to the operation, which may be termed the work to be done. Machines, in fact, are interposed between the power and the work, for the purpose of adapting the one to the other. [1]

In every fields, mechanization includes the use of hand tools. In modern usage, such as in engineering or economics, mechanization implies machinery more complex than hand tools and would not include simple devices such as an ungeared horse or donkey mill. Devices that cause speed changes or changes to or from reciprocating to rotary motion, using means such as gears, pulleys or sheaves and belts, shafts, cams and cranks, usually are considered machines. After electrification, when most small machinery was no longer hand powered, mechanization was synonymous with motorized machines. [2] Extension of mechanization of the production process is termed as automation and it is controlled by a closed loop system in which feedback is provided by the sensors. In an automated machine the work of different mechanisms is performed automatically. [3]

History

The Salisbury Cathedral clock ca. 1386. A clock is a mechanical instrument rather than a true machine. Although this clock had iron gears, many machines of the early Industrial Revolution used wooden parts until around 1800. Salisbury 02.jpg
The Salisbury Cathedral clock ca. 1386. A clock is a mechanical instrument rather than a true machine. Although this clock had iron gears, many machines of the early Industrial Revolution used wooden parts until around 1800.

Ancient times

Water wheels date to the Roman period and were used to grind grain and lift irrigation water. Water-powered bellows were in use on blast furnaces in China in 31 AD. [4] By the 13th century, water wheels powered sawmills [5] and trip hammers, to pull cloth and pound flax and later cotton rags into pulp for making paper. Trip hammers are shown crushing ore in De re Metallica (1555).

Clocks were some of the most complex early mechanical devices. Clock makers were important developers of machine tools including gear and screw cutting machines, and were also involved in the mathematical development of gear designs. Clocks were some of the earliest mass-produced items, beginning around 1830. [6] [7]

Water-powered bellows for blast furnaces, used in China in ancient times, were in use in Europe by the 15th century. De re Metallica contains drawings related to bellows for blast furnaces including a fabrication drawing.

Improved gear designs decreased wear and increased efficiency. Mathematical gear designs were developed in the mid 17th century. French mathematician and engineer Desargues designed and constructed the first mill with epicycloidal teeth ca. 1650. In the 18th century involute gears, another mathematical derived design, came into use. Involute gears are better for meshing gears of different sizes than epicycloidal. [7] Gear cutting machines came into use in the 18th century. [6]

Industrial revolution

The Newcomen steam engine was first used, to pump water from a mine, in 1712. John Smeaton introduced metal gears and axles to water wheels in the mid to last half of the 18th century. The Industrial Revolution started mainly with textile machinery, such as the spinning jenny (1764) and water frame (1768).

Demand for metal parts used in textile machinery led to the invention of many machine tools in the late 1700s until the mid-1800s. After the early decades of the 19th century, iron increasingly replaced wood in gearing and shafts in textile machinery. In the 1840s self acting machine tools were developed. Machinery was developed to make nails ca. 1810. The Fourdrinier paper machine for continuous production of paper was patented in 1801, displacing the centuries-old hand method of making individual sheets of paper.

One of the first mechanical devices used in agriculture was the seed drill invented by Jethro Tull around 1700. The seed drill allowed more uniform spacing of seed and planting depth than hand methods, increasing yields and saving valuable seed. In 1817, the first bicycle was invented and used in Germany. Mechanized agriculture greatly increased in the late eighteenth and early nineteenth centuries with horse drawn reapers and horse powered threshing machines. [8] By the late nineteenth century steam power was applied to threshing and steam tractors appeared. Internal combustion began being used for tractors in the early twentieth century. Threshing and harvesting was originally done with attachments for tractors, but in the 1930s independently powered combine harvesters were in use.

In the mid to late 19th century, hydraulic and pneumatic devices were able to power various mechanical actions, such as positioning tools or work pieces. [9] Pile drivers and steam hammers are examples for heavy work. In food processing, pneumatic or hydraulic devices could start and stop filling of cans or bottles on a conveyor. Power steering for automobiles uses hydraulic mechanisms, as does practically all earth moving equipment and other construction equipment and many attachments to tractors. Pneumatic (usually compressed air) power is widely used to operate industrial valves.

Twentieth century

By the early 20th century machines developed the ability to perform more complex operations that had previously been done by skilled craftsmen. [10] An example is the glass bottle making machine developed 1905. It replaced highly paid glass blowers and child labor helpers and led to the mass production of glass bottles. [11]

After 1900 factories were electrified, and electric motors and controls were used to perform more complicated mechanical operations. This resulted in mechanized processes to manufacture almost all goods.

Categories

Two involute gears, the left driving the right: Blue arrows show the contact forces between them. The force line (or Line of Action) runs along a tangent common to both base circles. (In this situation, there is no force, and no contact needed, along the opposite common tangent not shown.) The involutes here are traced out in converse fashion: points (of contact) move along the stationary force-vector "string" as if it was being unwound from the left rotating base circle, and wound onto the right rotating base circle. Involute wheel.gif
Two involute gears, the left driving the right: Blue arrows show the contact forces between them. The force line (or Line of Action) runs along a tangent common to both base circles. (In this situation, there is no force, and no contact needed, along the opposite common tangent not shown.) The involutes here are traced out in converse fashion: points (of contact) move along the stationary force-vector "string" as if it was being unwound from the left rotating base circle, and wound onto the right rotating base circle.

In manufacturing, mechanization replaced hand methods of making goods. Prime movers are devices that convert thermal, potential or kinetic energy into mechanical work. Prime movers include internal combustion engines, combustion turbines (jet engines), water wheels and turbines, windmills and wind turbines and steam engines and turbines. Powered transportation equipment such as locomotives, automobiles and trucks and airplanes, is a classification of machinery which includes sub classes by engine type, such as internal combustion, combustion turbine and steam. Inside factories, warehouses, lumber yards and other manufacturing and distribution operations, material handling equipment replaced manual carrying or hand trucks and carts. [10]

In mining and excavation, power shovels replaced picks and shovels. [10] Rock and ore crushing had been done for centuries by water-powered trip hammers, but trip hammers have been replaced by modern ore crushers and ball mills.

Bulk material handling systems and equipment are used for a variety of materials including coal, ores, grains, sand, gravel and wood products. [10]

Construction equipment includes cranes, concrete mixers, concrete pumps, cherry pickers and an assortment of power tools.

Powered machinery

Powered machinery today usually means either by electric motor or internal combustion engine. Before the first decade of the 20th century powered usually meant by steam engine, water or wind.

Many of the early machines and machine tools were hand powered, but most changed over to water or steam power by the early 19th century.

Before electrification, mill and factory power was usually transmitted using a line shaft. Electrification allowed individual machines to each be powered by a separate motor in what is called unit drive. Unit drive allowed factories to be better arranged and allowed different machines to run at different speeds. Unit drive also allowed much higher speeds, which was especially important for machine tools. [12]

A step beyond mechanization is automation. Early production machinery, such as the glass bottle blowing machine (ca. 1890s), required a lot of operator involvement. By the 1920s fully automatic machines, which required much less operator attention, were being used. [10]

Military usage

The term is also used in the military to refer to the use of tracked armoured vehicles, particularly armoured personnel carriers, to move troops ( mechanized infantry) that would otherwise have marched or ridden trucks into combat. In military terminology, mechanized refers to ground units that can fight from vehicles, while motorized refers to units (motorized infantry) that are transported and go to battle in unarmoured vehicles such as trucks. Thus, a towed artillery unit is considered motorized while a self-propelled one is mechanized.

Mechanical vs human labour

When we compare the efficiency of a labourer, we see that he has an efficiency of about 1%–5.5% (depending on whether he uses arms, or a combination of arms and legs). [13] Internal combustion engines mostly have an efficiency of about 20%, [14] although large diesel engines, such as those used to power ships, may have efficiencies of nearly 50%. Industrial electric motors have efficiencies up to the low 90% range, before correcting for the conversion efficiency of fuel to electricity of about 35%. [15]

When we compare the costs of using an internal combustion engine to a worker to perform work, we notice that an engine can perform more work at a comparative cost. 1 liter of fossil fuel burnt with an IC engine equals about 50 hands of workers operating for 24 hours or 275 arms and legs for 24 hours. [16] [17]

In addition, the combined work capability of a human is also much lower than that of a machine. An average human worker can provide work good for around 0,9 hp (2.3 MJ per hour) [18] while a machine (depending on the type and size) can provide for far greater amounts of work. For example, it takes more than one and a half hour of hard labour to deliver only one kWh – which a small engine could deliver in less than one hour while burning less than one litre of petroleum fuel. This implies that a gang of 20 to 40 men will require a financial compensation for their work at least equal to the required expended food calories (which is at least 4 to 20 times higher). In most situations, the worker will also want compensation for the lost time, which is easily 96 times greater per day. Even if we assume the real wage cost for the human labour to be at US $1.00/day, an energy cost is generated of about $4.00/kWh. Despite this being a low wage for hard labour, even in some of the countries with the lowest wages, it represents an energy cost that is significantly more expensive than even exotic power sources such as solar photovoltaic panels (and thus even more expensive when compared to wind energy harvesters or luminescent solar concentrators). [19]

Levels of mechanization

For simplification, one can study mechanization as a series of steps. [20] Many[ quantify ] students refer to this series as indicating basic-to-advanced forms of mechanical society. [21]

  1. hand/muscle power
  2. hand-tools
  3. powered hand-tools, e.g. electric-controlled
  4. powered tools, single functioned, fixed cycle
  5. powered tools, multi-functioned, program controlled
  6. powered tools, remote-controlled
  7. powered tools, activated by work-piece (e.g.: coin phone)
  8. measurement
  9. selected signaling control, e.g. hydro power control
  10. performance recording
  11. automated machine action altered through measurement
  12. segregation/rejection according to measurement
  13. selection of appropriate action cycle
  14. correcting performance after operation
  15. correcting performance during operation

See also

Related Research Articles

<span class="mw-page-title-main">Engine</span> Machine that converts one or more forms of energy into mechanical energy (of motion)

An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.

<span class="mw-page-title-main">Steam engine</span> Engine that uses steam to perform mechanical work

A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be transformed by a connecting rod and crank into rotational force for work. The term "steam engine" is most commonly applied to reciprocating engines as just described, although some authorities have also referred to the steam turbine and devices such as Hero's aeolipile as "steam engines". The essential feature of steam engines is that they are external combustion engines, where the working fluid is separated from the combustion products. The ideal thermodynamic cycle used to analyze this process is called the Rankine cycle. In general usage, the term steam engine can refer to either complete steam plants, such as railway steam locomotives and portable engines, or may refer to the piston or turbine machinery alone, as in the beam engine and stationary steam engine.

<span class="mw-page-title-main">Machine</span> Powered mechanical device

A machine is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolecules, such as molecular machines. Machines can be driven by animals and people, by natural forces such as wind and water, and by chemical, thermal, or electrical power, and include a system of mechanisms that shape the actuator input to achieve a specific application of output forces and movement. They can also include computers and sensors that monitor performance and plan movement, often called mechanical systems.

<span class="mw-page-title-main">Boiler</span> Closed vessel in which fluid is heated

A boiler is a closed vessel in which fluid is heated. The fluid does not necessarily boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.

<span class="mw-page-title-main">Machine tool</span> Machine for handling or machining metal or other rigid materials

A machine tool is a machine for handling or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of deformations. Machine tools employ some sort of tool that does the cutting or shaping. All machine tools have some means of constraining the workpiece and provide a guided movement of the parts of the machine. Thus, the relative movement between the workpiece and the cutting tool is controlled or constrained by the machine to at least some extent, rather than being entirely "offhand" or "freehand". It is a power-driven metal cutting machine which assists in managing the needed relative motion between cutting tool and the job that changes the size and shape of the job material.

<span class="mw-page-title-main">Stationary engine</span>

A stationary engine is an engine whose framework does not move. They are used to drive immobile equipment, such as pumps, generators, mills or factory machinery, or cable cars. The term usually refers to large immobile reciprocating engines, principally stationary steam engines and, to some extent, stationary internal combustion engines. Other large immobile power sources, such as steam turbines, gas turbines, and large electric motors, are categorized separately.

<span class="mw-page-title-main">Transmission (mechanical device)</span> Drivetrain transmitting propulsion power

A transmission is a mechanical device which uses a gear set—two or more gears working together—to change the speed, direction of rotation, or torque multiplication/reduction in a machine.

A millwright is a craftsman or skilled tradesman who installs, dismantles, maintains, repairs, reassembles, and moves machinery in factories, power plants, and construction sites.

Steam power developed slowly over a period of several hundred years, progressing through expensive and fairly limited devices in the early 17th century, to useful pumps for mining in 1700, and then to Watt's improved steam engine designs in the late 18th century. It is these later designs, introduced just when the need for practical power was growing due to the Industrial Revolution, that truly made steam power commonplace.

<span class="mw-page-title-main">Turbomachinery</span> Machine for exchanging energy with a fluid

Turbomachinery, in mechanical engineering, describes machines that transfer energy between a rotor and a fluid, including both turbines and compressors. While a turbine transfers energy from a fluid to a rotor, a compressor transfers energy from a rotor to a fluid. It is an important application of fluid mechanics.

<span class="mw-page-title-main">Mechanised agriculture</span> Agriculture using powered machinery

Mechanised agriculture or agricultural mechanization is the use of machinery and equipment, ranging from simple and basic hand tools to more sophisticated, motorized equipment and machinery, to perform agricultural operations. In modern times, powered machinery has replaced many farm task formerly carried out by manual labour or by working animals such as oxen, horses and mules.

<span class="mw-page-title-main">Line shaft</span> Rotating shaft historically used for power transmission

A line shaft is a power-driven rotating shaft for power transmission that was used extensively from the Industrial Revolution until the early 20th century. Prior to the widespread use of electric motors small enough to be connected directly to each piece of machinery, line shafting was used to distribute power from a large central power source to machinery throughout a workshop or an industrial complex. The central power source could be a water wheel, turbine, windmill, animal power or a steam engine. Power was distributed from the shaft to the machinery by a system of belts, pulleys and gears known as millwork.

<span class="mw-page-title-main">Thermal power station</span> Power plant that generates electricity from heat energy

A thermal power station, also known as a thermal power plant, is a type of power station in which the heat energy generated from various fuel sources is converted to electrical energy. The heat from the source is converted into mechanical energy using a thermodynamic power cycle. The most common cycle involves a working fluid heated and boiled under high pressure in a pressure vessel to produce high-pressure steam. This high pressure-steam is then directed to a turbine, where it rotates the turbine's blades. The rotating turbine is mechanically connected to an electric generator which converts rotary motion into electricity. Fuels such as natural gas or oil can also be burnt directly in gas turbines, skipping the steam generation step. These plants can be of the open cycle or the more efficient combined cycle type.

Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-

  1. Internal combustion and
  2. External combustion engines.

The following outline is provided as an overview of and topical guide to machines:

<span class="mw-page-title-main">Mechanical Engineering Heritage (Japan)</span> Certified items of significance

The Mechanical Engineering Heritage (Japan) (機械遺産, kikaiisan) is a list of sites, landmarks, machines, and documents that made significant contributions to the development of mechanical engineering in Japan. Items in the list are certified by the Japan Society of Mechanical Engineers (JSME) (日本機械学会, Nihon Kikai Gakkai).

<span class="mw-page-title-main">History of the steam engine</span> Heat engine that performs mechanical work using steam as its working fluid

The first recorded rudimentary steam engine was the aeolipile mentioned by Vitruvius between 30 and 15 BC and, described by Heron of Alexandria in 1st-century Roman Egypt. Several steam-powered devices were later experimented with or proposed, such as Taqi al-Din's steam jack, a steam turbine in 16th-century Ottoman Egypt, Denis Papin's working model of the steam digester in 1679 and Thomas Savery's steam pump in 17th-century England. In 1712, Thomas Newcomen's atmospheric engine became the first commercially successful engine using the principle of the piston and cylinder, which was the fundamental type of steam engine used until the early 20th century. The steam engine was used to pump water out of coal mines.

<span class="mw-page-title-main">Agricultural machinery</span> Machinery used in farming or other agriculture

Agricultural machinery relates to the mechanical structures and devices used in farming or other agriculture. There are many types of such equipment, from hand tools and power tools to tractors and the farm implements that they tow or operate. Machinery is used in both organic and nonorganic farming. Especially since the advent of mechanised agriculture, agricultural machinery is an indispensable part of how the world is fed.

<span class="mw-page-title-main">Productivity-improving technologies</span> Technological innovations that have historically increased productivity

The productivity-improving technologies are the technological innovations that have historically increased productivity.

<span class="mw-page-title-main">Machine industry</span> Subsector of the industry

The machine industry or machinery industry is a subsector of the industry, that produces and maintains machines for consumers, the industry, and most other companies in the economy.

References

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  2. Jerome (1934) gives the industry classification of machine tools as being "other than hand power". Beginning with the 1900 U.S. census, power use was part of the definition of a FACTORY , distinguishing it from a workshop.
  3. Mechanization & Automation [usurped] , Mechanical Engineering Community, retrieved 2018-04-17.
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  7. 1 2 Musson; Robinson (1969). Science and Technology in the Industrial Revolution . University of Toronto Press. p.  69. ISBN   9780802016379.
  8. Rumeley, Edward A. (August 1910). "The Passing Of The Man With The Hoe". The World's Work: A History of Our Time . XX: 13246–13258. Retrieved 2009-07-10.
  9. Hunter, Louis C.; Bryant, Lynwood (1991). A History of Industrial Power in the United States, 1730–1930, Vol. 3: The Transmission of Power . Cambridge, Massachusetts, London: MIT Press. ISBN   0-262-08198-9.
  10. 1 2 3 4 5 Jerome, Harry (1934). Mechanization in Industry, National Bureau of Economic Research (PDF).
  11. "The American Society of Mechanical Engineers Designates the Owens "AR" Bottle Machine as an International Historic Engineering Landmark" (PDF). 1983. Archived from the original (PDF) on 2013-04-05.
  12. Bartelt, Terry. Industrial Automated Systems: Instrumentation and Motion Control. Cengage Learning, 2010.
  13. Ayres, R. U.; Ayres, L. W.; Warr, B. (2002). Exergy, Power and Work in the U. S. Economy 1900–1998, Insead's Center For the Management of Environmental Resources, 2002/52/EPS/CMER (PDF) (Report).
  14. IC Engine 20% efficient
  15. "Electrical engines with combined power converter / motor at 86% efficiency". Archived from the original on 2016-03-05. Retrieved 2011-03-22.
  16. 1 liter of fuel yielding 100 arms for 24 hours, when efficiency is 40% which is never
  17. Home documentary by Yann Arthus Bertrand too stating that 1 liter of fuel yields 100 arms for 24 hours; probably from same calculation
  18. Ozkan, Burhan (2004). "Energy input–output analysis in Turkish agriculture" (PDF). Renewable Energy. 29 (1): 39. Bibcode:2004REne...29...39O. doi:10.1016/s0960-1481(03)00135-6. Archived from the original (PDF) on 2022-05-25. Retrieved 2018-04-20.
  19. Combined work capability of human vs machines
  20. "Mechanization and its level". Archived from the original on 2011-08-15. Retrieved 2010-05-13.
  21. basic-to-advanced Archived 2011-08-15 at the Wayback Machine

Further reading