Lean manufacturing

Lean manufacturing is a method of manufacturing goods aimed primarily at reducing times within the production system as well as response times from suppliers and customers. It is closely related to another concept called just-in-time manufacturing (JIT manufacturing in short). Just-in-time manufacturing tries to match production to demand by only supplying goods that have been ordered and focus on efficiency, productivity (with a commitment to continuous improvement), and reduction of "wastes" for the producer and supplier of goods. Lean manufacturing adopts the just-in-time approach and additionally focuses on reducing cycle, flow, and throughput times by further eliminating activities that do not add any value for the customer.^[1] Lean manufacturing also involves people who work outside of the manufacturing process, such as in marketing and customer service.

Lean manufacturing (also known as agile manufacturing) is particularly related to the operational model implemented in the post-war 1950s and 1960s by the Japanese automobile company Toyota called the Toyota Production System (TPS), known in the United States as "The Toyota Way".^[2]^[3] Toyota's system was erected on the two pillars of just-in-time inventory management and automated quality control.

The seven "wastes" (muda in Japanese), first formulated by Toyota engineer Shigeo Shingo, are:

the waste of superfluous inventory of raw material and finished goods
the waste of overproduction (producing more than what is needed now)
the waste of over-processing (processing or making parts beyond the standard expected by customer),
the waste of transportation (unnecessary movement of people and goods inside the system)
the waste of excess motion (mechanizing or automating before improving the method)
the waste of waiting (inactive working periods due to job queues)
and the waste of making defective products (reworking to fix avoidable defects in products and processes).^[4]

The term Lean was coined in 1988 by American businessman John Krafcik in his article "Triumph of the Lean Production System," and defined in 1996 by American researchers Jim Womack and Dan Jones to consist of five key principles: "Precisely specify value by specific product, identify the value stream for each product, make value flow without interruptions, let customer pull value from the producer, and pursue perfection."^[5]

Companies employ the strategy to increase efficiency. By receiving goods only as they need them for the production process, it reduces inventory costs and wastage, and increases productivity and profit. The downside is that it requires producers to forecast demand accurately as the benefits can be nullified by minor delays in the supply chain. It may also impact negatively on workers due to added stress and inflexible conditions. A successful operation depends on a company having regular outputs, high-quality processes, and reliable suppliers.

^ According to Kamarudin Abu Bakar; Mohd Fazli Mohd. Sam; M.I. Qureshi (2022), "Lean Manufacturing Design of a Two-Sided Assembly Line Balancing Problem Work Cell", in Mohd Najib Ali Mokhtar; Zamberi Jamaludin; Mohd Sanusi Abdul Aziz; Mohd Nazmin Maslan; Jeeferie Abd Razak (eds.), Intelligent Manufacturing and Mechatronics: Proceedings of SympoSIMM 2021, Springer Nature, p. 250: "While Just-In-Time manufacturing focuses on efficiency of inventory strategy to eliminate waste and enhance productivity, Lean manufacturing uses efficiency in its system setups to reduce cycle, flow, and throughput times being the added values to customers."
^ Ohno, Taiichi (1988). Toyota Production System: Beyond Large-Scale Production. CRC Press. ISBN 978-0-915299-14-0.
^ Shingo, Shigeo. 1985. A Revolution in Manufacturing: The SMED System. Stamford, Ct.: Productivity Press
^ Jonathan Law, ed. (2009), A Dictionary of Business and Management, Oxford University Press
^ Womack, James P.; Jones, Daniel T. (2003), Lean Thinking: Banish Waste And Create Wealth In Your Corporation, Simon and Schuster, p. 10, ISBN 9781471111006, archived from the original on October 22, 2021, retrieved October 2, 2020

[1] According to Kamarudin Abu Bakar; Mohd Fazli Mohd. Sam; M.I. Qureshi (2022), "Lean Manufacturing Design of a Two-Sided Assembly Line Balancing Problem Work Cell", in Mohd Najib Ali Mokhtar; Zamberi Jamaludin; Mohd Sanusi Abdul Aziz; Mohd Nazmin Maslan; Jeeferie Abd Razak (eds.), Intelligent Manufacturing and Mechatronics: Proceedings of SympoSIMM 2021, Springer Nature, p. 250: "While Just-In-Time manufacturing focuses on efficiency of inventory strategy to eliminate waste and enhance productivity, Lean manufacturing uses efficiency in its system setups to reduce cycle, flow, and throughput times being the added values to customers."

[2] Ohno, Taiichi (1988). Toyota Production System: Beyond Large-Scale Production. CRC Press. ISBN 978-0-915299-14-0.

[Shingo-3] Shingo, Shigeo. 1985. A Revolution in Manufacturing: The SMED System. Stamford, Ct.: Productivity Press

[4] Jonathan Law, ed. (2009), A Dictionary of Business and Management, Oxford University Press

[5] Womack, James P.; Jones, Daniel T. (2003), Lean Thinking: Banish Waste And Create Wealth In Your Corporation, Simon and Schuster, p. 10, ISBN 9781471111006, archived from the original on October 22, 2021, retrieved October 2, 2020

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