<P> Mass production benefited from the development of materials such as inexpensive steel, high strength steel and plastics . Machining of metals was greatly enhanced with high speed steel and later very hard materials such as tungsten carbide for cutting edges . Fabrication using steel components was aided by the development of electric welding and stamped steel parts, both which appeared in industry in about 1890 . Plastics such as polyethylene, polystyrene and polyvinyl chloride (PVC) can be easily formed into shapes by extrusion, blow molding or injection molding, resulting in very low cost manufacture of consumer products, plastic piping, containers and parts . </P> <P> An influential article that helped to frame and popularize the 20th century's definition of mass production appeared in a 1926 Encyclopædia Britannica supplement . The article was written based on correspondence with Ford Motor Company and is sometimes credited as the first use of the term . </P> <P> Electrification of factories began very gradually in the 1890s after the introduction of a practical DC motor by Frank J. Sprague and accelerated after the AC motor was developed by Galileo Ferraris, Nikola Tesla and Westinghouse, Mikhail Dolivo - Dobrovolsky and others . Electrification of factories was fastest between 1900 and 1930, aided by the establishment of electric utilities with central stations and the lowering of electricity prices from 1914 to 1917 . </P> <P> Electric motors were several times more efficient than small steam engines because central station generation were more efficient than small steam engines and because line shafts and belts had high friction losses . Electric motors allowed also more flexibility in manufacturing and required less maintenance than line shafts and belts . Many factories saw a 30% increase in output just from changing over to electric motors . </P>

Assembly lines improved productivity by using interchangeable parts and craft production