Lean manufacturing is a production method aimed primarily at reducing times within the production system as well as response times from suppliers and to 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 which have been ordered and focuses 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 which do not add any value for the customer. Lean manufacturing also involves people who work outside of the manufacturing process, such as in marketing and customer service. Lean manufacturing is particularly related to the operational model implemented in the post-war 1950s and 1960s by the Japanese automobile company Toyota called Toyota Production System (TPS), kown in the USA as "The Toyota Way". 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).
Jérôme Chenal, Baraka Jean-Claude Munyaka