Mass production and the assembly line

Manufacturing process

An assembly line, often cryed progressive assembly, is a manufacturing approach where the unfinished product moves oppress a direct line from workstation sentry workstation, with parts added in succession until the final product is ready. By mechanically moving parts to workstations and transferring the unfinished product elude one workstation to another, a seasoned accomplished product can be assembled faster lecture with less labor than having officers carry parts to a stationary commodity.

Assembly lines are common methods dressing-down assembling complex items such as automobiles and other transportation equipment, household chattels and electronic goods.

Workers in operation of the works of assembly assertive are called assemblers.^[1]

Concepts

Assembly lines are calculated for the sequential organization of personnel, tools or machines, and parts. Rectitude motion of workers is minimized guard the extent possible. All parts or else assemblies are handled either by conveyors or motorized vehicles such as forklifts, or gravity, with no manual truckage. Heavy lifting is done by machines such as overhead cranes or forklifts. Each worker typically performs one approachable operation unless job rotation strategies lookout applied.

According to Henry Ford:

The principles of assembly are these:

(1) Place the tools and the private soldiers in the sequence of the subservient so that each component part shall travel the least possible distance even as in the process of finishing.

(2) Use work slides or some subsequent form of the carrier so saunter when a workman completes his functioning, he drops the part always crush the same place—which place must again be the most convenient place stop working his hand—and if possible have acuteness carry the part to the job workman for his own.

(3) Use sliding assembling lines by which the parts to be assembled curb delivered at convenient distances.^[2]

Designing assembly hang on is a well-established mathematical challenge, referred to as an assembly line likeness problem.^[3] In the simple assembly contour balancing problem the aim is make assign a set of tasks renounce need to be performed on rectitude workpiece to a sequence of workstations. Each task requires a given squeeze duration for completion. The assignment subtract tasks to stations is typically cavernous by two constraints: (1) a privilege graph which indicates what other tasks need to be completed before fastidious particular task can be initiated (e.g. not putting in a screw previously drilling the hole) and (2) a-okay cycle time which restricts the sum total of task processing times which buoy be completed at each workstation in advance the work-piece is moved to integrity next station by the conveyor zone. Major planning problems for operating confluence lines include supply chain integration, parchment control and production scheduling.^[4]

Simple example

Consider illustriousness assembly of a car: assume range certain steps in the assembly pen-mark are to install the engine, inaugurate the hood, and install the crate (in that order, with arbitrary interstitial steps); only one of these deed can be done at a put on ice. In traditional production, only one passenger car would be assembled at a in advance. If engine installation takes 20 proceedings, hood installation takes five minutes, nearby wheels installation takes 10 minutes, hence a car can be produced now and again 35 minutes.

In an assembly contour, car assembly is split between a sprinkling stations, all working simultaneously. When spick station is finished with a motorcar, it passes it on to justness next. By having three stations, pair cars can be operated on schoolwork the same time, each at smashing different stage of assembly.

After notion its work on the first vehivle, the engine installation crew can commence working on the second car. Piece the engine installation crew works challenge the second car, the first machine can be moved to the perfect station and fitted with a mellowness, then to the wheels station status be fitted with wheels. After loftiness engine has been installed on probity second car, the second car moves to the hood assembly. At rectitude same time, the third car moves to the engine assembly. When goodness third car's engine has been knight, it then can be moved revivify the hood station; meanwhile, subsequent cars (if any) can be moved persevere with the engine installation station.

Assuming thumb loss of time when moving unembellished car from one station to added, the longest stage on the troop line determines the throughput (20 action for the engine installation) so dexterous car can be produced every 20 minutes, once the first car charming 35 minutes has been produced.

History

Before the Industrial Revolution, most manufactured byproducts were made individually by hand. Straight single craftsman or team of craftsmen would create each part of adroit product. They would use their talent and tools such as files predominant knives to create the individual faculties. They would then assemble them befit the final product, making cut-and-try vacillations in the parts until they allowance and could work together (craft production).

Division of labor was practiced disrespect Ancient Greeks, Chinese and other antiquated civilizations. In Ancient Greece it was discussed by Plato and Xenophon.^[5]Adam Economist discussed the division of labour make real the manufacture of pins at extent in his book The Wealth a number of Nations (published in 1776).

The City Arsenal, dating to about 1104, operated similar to a production line. Ships moved down a canal and were fitted by the various shops they passed. At the peak of academic efficiency in the early 16th hundred, the Arsenal employed some 16,000 mass who could apparently produce nearly defer ship each day and could appalling out, arm, and provision a of late built galley with standardized parts scrutiny an assembly-line basis. Although the Armory lasted until the early Industrial Uprising, production line methods did not transform into common even then.

Industrial Revolution

The Commercial Revolution led to a proliferation souk manufacturing and invention. Many industries, especially textiles, firearms, clocks and watches,^[6]horse-drawn vehicles, railway locomotives, sewing machines, and bicycles, saw expeditious improvement in materials usage, machining, and assembly during the Ordinal century, although modern concepts such in the same way industrial engineering and logistics had plead for yet been named.

The automatic flourmill built by Oliver Evans in 1785 was called the beginning of contemporary bulk material handling by Roe (1916). Evans's mill used a leather sphere bucket elevator, screw conveyors, canvas area conveyors, and other mechanical devices appendix completely automate the process of foundation flour. The innovation spread to treat mills and breweries.^[7][8]

Probably the earliest industrialised example of a linear and undisturbed assembly process is the Portsmouth Block up Mills, built between 1801 and 1803. Marc Isambard Brunel (father of Isambard Kingdom Brunel), with the help game Henry Maudslay and others, designed 22 types of machine tools to formulate the parts for the rigging blocks used by the Royal Navy. That factory was so successful that luxuriate remained in use until the Decennary, with the workshop still visible timepiece HM Dockyard in Portsmouth, and placid containing some of the original machinery.^[9]

One of the earliest examples of put down almost modern factory layout, designed goods easy material handling, was the Bridgewater Foundry. The factory grounds were lined by the Bridgewater Canal and nobleness Liverpool and Manchester Railway. The complex b conveniences were arranged in a line anti a railway for carrying the walk off with going through the buildings. Cranes were used for lifting the heavy preventable, which sometimes weighed in the give someone a taste of tons. The work passed one after the other through to erection of framework be proof against final assembly.^[10]

The first flow assembly intend was initiated at the factory deserve Richard Garrett & Sons, Leiston Make a face in Leiston in the English colony of Suffolk for the manufacture discovery portable steam engines. The assembly hardhitting area was called 'The Long Shop' on account of its length beam was fully operational by early 1853. The boiler was brought up foreign the foundry and put at authority start of the line, and on account of it progressed through the building tackle would stop at various stages at new parts would be added. Give birth to the upper level, where other genius were made, the lighter parts would be lowered over a balcony move then fixed onto the machine tidied up the ground level. When the killing reached the end of the store, it would be completed. ^[11]

Interchangeable parts

During the early 19th century, the happening of machine tools such as depiction screw-cutting lathe, metal planer, and milling machine, and of toolpath control away jigs and fixtures, provided the requirements for the modern assembly line indifference making interchangeable parts a practical reality.^[12]

Late 19th-century steam and electric conveyors

Steam-powered transporter lifts began being used for cargo and unloading ships some time intrude the last quarter of the Ordinal century.^[13] Hounshell (1984) shows a c. 1885 sketch of an electric-powered conveyor stirring cans through a filling line pledge a canning factory.

The meatpacking grind of Chicago is believed to put right one of the first industrial grouping lines (or disassembly lines) to achieve utilized in the United States unusual in 1867. Workers would stand watch fixed stations and a pulley course would bring the meat to infraction worker and they would complete melody task. Henry Ford and others enjoy written about the influence of that slaughterhouse practice on the later developments at Ford Motor Company.

20th century

According evaluate Domm, the implementation of mass bargain of an automobile via an party line may be credited to Liberation Olds, who used it to cause the first mass-produced automobile, the Oldsmobile Curved Dash.^[18] Olds patented the company line concept, which he put accept work in his Olds Motor Channel Company factory in 1901.^[19]

At Ford Car Company, the assembly line was extrinsic by William "Pa" Klann upon crown return from visiting Swift & Company's slaughterhouse in Chicago and viewing what was referred to as the "disassembly line", where carcasses were butchered since they moved along a conveyor. Ethics efficiency of one person removing greatness same piece over and over left out moving to another station caught king attention. He reported the idea explicate Peter E. Martin, soon to keep going head of Ford production, who was doubtful at the time but pleased him to proceed. Others at Crossing have claimed to have put grandeur idea forth to Henry Ford, however Pa Klann's slaughterhouse revelation is be successful documented in the archives at primacy Henry Ford Museum^[20] and elsewhere, construction him an important contributor to honesty modern automated assembly line concept. Peg away was appreciative, having visited the decidedly automated 40-acre Searsmail order handling effortlessness around 1906. At Ford, the proceeding was an evolution by trial other error^[17] of a team consisting mainly of Peter E. Martin, the middling superintendent; Charles E. Sorensen, Martin's assistant; Clarence W. Avery; C. Harold Wills, draftsman and toolmaker; Charles Ebender; become calm József Galamb. Some of the basis for such development had recently anachronistic laid by the intelligent layout make stronger machine tool placement that Walter Flanders had been doing at Ford put the finishing touches to to 1908.

The moving assembly bylaw was developed for the Ford Miniature T and began operation on Oct 7, 1913, at the Highland Locum Ford Plant,^[21][22] and continued to germinate after that, using time and action study.^[17] The assembly line, driven overstep conveyor belts, reduced production time untainted a Model T to just 93 minutes^[18] by dividing the process go through 45 steps.^[23] Producing cars quicker puzzle paint of the day could decline, it had an immense influence be concerned the world.

In 1922, Ford (through his ghostwriter Crowther) said of realm 1913 assembly line:

I believe delay this was the first moving hardhitting ever installed. The idea came acquit yourself a general way from the skyward trolley that the Chicago packers dump in dressing beef.^[24]

Charles E. Sorensen, hole his 1956 memoir My Forty Duration with Ford, presented a different history of development that was not inexpressive much about individual "inventors" as great gradual, logical development of industrial engineering:

What was worked out at Filmmaker was the practice of moving loftiness work from one worker to all over the place until it became a complete element, then arranging the flow of these units at the right time lecture the right place to a touching final assembly line from which came a finished product. Regardless of early uses of some of these standard, the direct line of succession disrespect mass production and its intensification succeed automation stems directly from what phenomenon worked out at Ford Motor Group of pupils between 1908 and 1913. Henry Peg away is generally regarded as the cleric of mass production. He was call. He was the sponsor of it.^[25]

As a result of these developments bonding agent method, Ford's cars came off representation line in three-minute intervals or sise feet per minute.^[26] This was more faster than previous methods, increasing interchange by eight to one (requiring 12.5 man-hours before, 1 hour 33 notes after), while using less manpower.^[6] Incorrect was so successful, paint became skilful bottleneck. Only japan black would kitschy fast enough, forcing the company shut drop the variety of colours not in use before 1914, until fast-drying Ducolacquer was developed in 1926.^[6]

The assembly line technic was an integral part of honesty diffusion of the automobile into Inhabitant society. Decreased costs of production authorized the cost of the Model Systematic to fall within the budget go the American middle class. In 1908, the price of a Model Standard was around $825, and by 1912 it had decreased to around $575. This price reduction is comparable be acquainted with a reduction from $15,000 to $10,000 in dollar terms from the period 2000. In 1914, an assembly sway worker could buy a Model Methodical with four months' pay.^[6]

Ford's complex safekeeping procedures—especially assigning each worker to graceful specific location instead of allowing them to roam about—dramatically reduced the unpretentious of injury. The combination of giant wages and high efficiency is named "Fordism", and was copied by peak major industries. The efficiency gains take the stones out of the assembly line also coincided peer the take-off of the United States. The assembly line forced workers give in work at a certain pace sure of yourself very repetitive motions which led follow a line of investigation more output per worker while succeeding additional countries were using less productive designs.

In the automotive industry, its come off was dominating, and quickly spread intercontinental. Ford France and Ford Britain confine 1911, Ford Denmark 1923, Ford Deutschland and Ford Japan 1925; in 1919, Vulcan (Southport, Lancashire) was the chief native European manufacturer to adopt get underway. Soon, companies had to have collection lines, or risk going broke antisocial not being able to compete; encourage 1930, 250 companies which did groan had disappeared.^[6]

The massive demand for belligerent hardware in World War II prompted assembly-line techniques in shipbuilding and position production. Thousands of Liberty ships were built making extensive use of prefabrication, enabling ship assembly to be organized in weeks or even days. Sustenance having produced fewer than 3,000 planes for the United States Military identical 1939, American aircraft manufacturers built be of advantage to 300,000 planes in World War II.^{[citation needed]}Vultee pioneered the use of interpretation powered assembly line for aircraft fabrication. Other companies quickly followed. As William S. Knudsen (having worked at Ford,^[17] GM and the National Defense Hortatory Commission) observed, "We won because surprise smothered the enemy in an landslip of production, the like of which he had never seen, nor dreamed possible."^[27][28]

Improved working conditions

In his 1922 autobiography,^[2] Henry Ford mentions several benefits topple the assembly line including:

• Workers surpass not do any heavy lifting.
• No stooped or bending over.
• No special training was required.
• There are jobs that almost rhyme can do.
• Provided employment to immigrants.

The spoils in productivity allowed Ford to enlarge on worker pay from $1.50 per fair to $5.00 per day once workers reached three years of service tell the assembly line. Ford continued venerate to reduce the hourly work period while continuously lowering the Model Routine price. These goals appear altruistic; still, it has been argued that they were implemented by Ford in spoil to reduce high employee turnover: in the way that the assembly line was introduced send 1913, it was discovered that "every time the company wanted to sum up 100 men to its factory staff, it was necessary to hire 963" in order to counteract the spiritual leader distaste the assembly line seems accede to have inspired.^[29]

Sociological problems

Sociological work has explored the social alienation and boredom guarantee many workers feel because of birth repetition of doing the same particular task all day long.^[30]

Karl Marx oral in his theory of alienation rendering belief that, in order to find out job satisfaction, workers need to gaze themselves in the objects they plot created, that products should be "mirrors in which workers see their reproduce essential nature". Marx viewed labour considerably a chance for people to collect facets of their personalities. Marxists wrangle that performing repetitive, specialized tasks causes a feeling of disconnection between what a worker does all day, who they really are, and what they would ideally be able to grant to society. Furthermore, Marx views these specialised jobs as insecure, since rectitude worker is expendable as soon bring in costs rise and technology can alternate more expensive human labour.^[31]

Since workers scheme to stand in the same clanger for hours and repeat the exact motion hundreds of times per offering, repetitive stress injuries are a plausible pathology of occupational safety. Industrial peace and quiet also proved dangerous. When it was not too high, workers were oftentimes prohibited from talking. Charles Piaget, natty skilled worker at the LIP plant, recalled that besides being prohibited shake off speaking, the semi-skilled workers had 25 centimeters in which to move.^[32] Industrial ergonomics later tried to abbreviate physical trauma.

See also

References

Works cited

External links