Mass production is the name given to the method of producing goods in large quantities at low cost per unit. But mass production, although allowing lower prices, does not have to mean low-quality production. Instead, mass-produced goods are standardized by means of precision-manufactured, interchangeable parts. The mass production process itself is characterized by mechanization to achieve high volume, elaborate organization of materials flow through various stages of manufacturing, careful supervision of quality standards, and minute division of labour. To make it worthwhile, mass production requires mass consumption. Until relatively recent times the only large-scale demand for standardized, uniform products came from military organizations. The major experiments that eventually led to mass production were first performed under the aegis of the military.

Machine tools and interchangeable parts The material basis for mass production was laid by the development of the machine-tool industry--that is, the making of machines to make machines. Though some basic devices such as the woodworking lathe had existed for centuries, their translation into industrial machine tools capable of cutting and shaping hard metals to precise tolerances was brought about by a series of 19th-century innovators, first in Britain and later in the United States. With precision equipment, large numbers of identical parts could be produced at low cost and with a small work force.

The system of manufacture involving production of many identical parts and their assembly into finished products came to be called the American System, because it achieved its fullest maturity in the United States. Although Eli Whitney has been given credit for this development, his ideas had appeared earlier in Sweden, France, and Britain and were being practiced in arms factories in the United States. During the years 1802-08, for example, the French émigré engineer Marc Brunel, while working for the British Admiralty in the Portsmouth Dockyard, devised a process for producing wooden pulley blocks by sequential machine operations. Ten men, in place of 110 needed previously, were able to make 160,000 pulley blocks per year. British manufacturers, however, ignored Brunel's ideas, and it was not until London's Crystal Palace exhibition of 1851 that British engineers, viewing exhibits of machines used in the United States to produce interchangeable parts, began to apply the system. By the third quarter of the 19th century, the American System was employed in making small arms, clocks, textile machinery, sewing machines, and a host of other industrial products.

The assembly line. Though prototypes of the assembly line can be traced to antiquity, the true ancestor of this industrial technique was the 19th-century meat-packing industry in Cincinnati, Ohio, and in Chicago, where overhead trolleys were employed to convey carcasses from worker to worker. When these trolleys were connected with chains and power was used to move the carcasses past the workers at a steady pace, they formed a true assembly line (or in effect a "disassembly" line in the case of meat cutters). Stationary workers concentrated on one task, performing it at a pace dictated by the machine, minimizing unnecessary movement, and dramatically increasing productivity.

Drawing upon observations of the meat-packing industry, the American automobile manufacturer Henry Ford designed an assembly line that began operation in 1913. The result was a remarkable reduction of manufacturing time for magneto flywheels from 20 minutes to five minutes. This success stimulated Ford to apply the technique to chassis assembly. Under the old system, by which parts were carried to a stationary assembly point, 12 1/2 man-hours were required for each chassis. Using a rope to pull the chassis past stockpiles of components, Ford cut labour time to six man-hours. With improvements--a chain drive to power assembly-line movement, stationary locations for the workmen, and work stations designed for convenience and comfort--assembly time fell to 93 man-minutes by the end of April 1914. Ford's methods drastically reduced the price of a private automobile, bringing it within the reach of the common man. (see also Index: automotive industry ) Ford's spectacular feats forced both his competitors and his parts suppliers to initiate his technique, and the assembly line spread through a large part of U.S. industry, bringing dramatic gains in productivity and causing skilled workers to be replaced with low-cost unskilled labour. Because the pace of the assembly line was dictated by machines, the temptation arose to accelerate the machines, forcing the workers to keep up. Such speedups became a serious point of contention between labour and management, while the dull, repetitive nature of many assembly-line jobs bored employees, reducing their output.

Effects on the organization of work. The development of mass production transformed the organization of work in three important ways. First, tasks were minutely subdivided and performed by unskilled workers, or at least semiskilled workers, since much of the skill was built into the machine. Second, manufacturing concerns grew to such size that a large hierarchy of supervisors and managers became necessary. Third, the increasing complexity of operations required employment of a large management staff of accountants, engineers, chemists, and, later, social psychologists, in addition to a large distribution and sales force. Mass production also heightened the trend toward an international division of labour. The huge new factories often needed raw materials from abroad, while saturation of national markets led to a search for customers overseas. Thus, some countries became exporters of raw materials and importers of finished goods, while others did the reverse.

In the 1970s and '80s some countries, particularly in Asia and South America, that had hitherto been largely agricultural and that had imported manufactured goods began industrializing. The skills needed by workers on assembly-line tasks were easily acquired, and standards of living in these developing countries were so low that wages could be kept below those of the already industrialized nations. Many large manufacturers in the United States and elsewhere therefore began "outsourcing"--that is, having parts made or whole products assembled in developing nations. Consequently, those countries are rapidly becoming integrated into the world economic community.