Just in time (business)

Just-in-time (JIT) manufacturing, also known as just-in-time production or the Toyota Production System (TPS), is a methodology aimed primarily at reducing flow times within production system as well as response times from suppliers and to customers. Following its origin and development in Japan, largely in the 1960s and 1970s and particularly at Toyota.

Alternative terms for JIT manufacturing have been used. Motorola's choice was short-cycle manufacturing (SCM). IBM's was continuous-flow manufacturing (CFM), and demand-flow manufacturing (DFM), a term handed down from consultant John Constanza at his Institute of Technology in Colorado. Still another alternative was mentioned by Goddard, who said that "Toyota Production System is often mistakenly referred to as the 'Kanban System,'" and pointed out that kanban is but one element of TPS, as well as JIT production.

But the wide use of the term JIT manufacturing throughout the 1980s faded fast in the 1990s, as the new term lean manufacturing became established as "a more recent name for JIT." As just one testament to the commonality of the two terms, Toyota production system (TPS) has been and is widely used as a synonym for both JIT and lean manufacturing.

The exact reasons for JIT evolution in Japan are unclear. Plenert offers four reasons, paraphrased here. During Japan's post-World War II rebuilding of industry: 1. Japan's lack of cash made it difficult for industry to finance the big-batch, large inventory production methods common elsewhere. 2. Japan lacked space to build big factories loaded with inventory. 3. The Japanese islands were (and are) lacking in natural resources with which to build products. 4. Japan had high unemployment, which meant that labor efficiency methods were not an obvious pathway to industrial success. Thus the Japanese "leaned out" their processes. "They built smaller factories . . . in which the only materials housed in the factory were those on which work was currently being done. In this way, inventory levels were kept low, investment in in-process inventories was at a minimum, and the investment in purchased natural resources was quickly turned around so that additional materials were purchased." Plenart goes on to explain Toyota's key role in developing this lean or JIT production methodology.

News about JIT/TPS reached western shores in 1977 in two English-language articles: One referred to the methodology as the "Ohno system," after Taiichi Ohno, who was instrumental in its development within Toyota. The other article, by Toyota authors in an international journal, provided additional details. Finally, those and other publicity were translated into implementations, beginning in 1980 and then quickly multiplying throughout industry in the United States and other developed countries. A seminal 1980 event was a conference in Detroit at Ford World Headquarters co-sponsored by the Repetitive Manufacturing Group (RMG), which had been founded 1979 within the American Production and Inventory Control Society (APICS) to seek advances in manufacturing. The principle speaker, Fujio Cho (later, president of Toyota Motor Corp.), in explaining the Toyota system, stirred up the audience, and led to the RMG's shifting gears from things like automation to JIT/TPS.

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