Factory

A factory (previously manufactory) or manufacturing plant is an industrial site, usually consisting of buildings and machinery, or more commonly a complex having several buildings, where workers manufacture goods or operate machines processing one product into another.

Factories arose with the introduction of machinery during the Industrial Revolution when the capital and space requirements became too great for cottage industry or workshops. Early factories that contained small amounts of machinery, such as one or two spinning mules, and fewer than a dozen workers have been called "glorified workshops.

Most modern factories have large warehouses or warehouse-like facilities that contain heavy equipment used for assembly line production. Large factories tend to be located with access to multiple modes of transportation, with some having rail, highway and water loading and unloading facilities.

Factories may either make discrete products or some type of material continuously produced such as chemicals, pulp and paper or refined oil products. Factories manufacturing chemicals are often called plants and may have most of their equipment, consisting of tanks, pressure vessels, chemical reactors and pumps and piping located outdoors and are operated by personnel in control rooms. Oil refineries are similar to chemical plants in that most equipment is outdoors.

Discrete products may range from parts to components and assemblies which are made into final products elsewhere or they may make final products. Factories may start from parts supplied from elsewhere or may make parts from raw materials. Industries making continuous materials, sometimes called process industries, typically use energy, usually heat, electricity or both, to transform raw materials into finished product.

The term mill properly refers to milling of grain, which which was usually done by water power from ancient times until displaced by steam power in the 19th century. Because many processes like spinning and weaving, iron rolling, and paper manufacturing were originally powered by water, the term survives such as steel mill, paper mill, etc.