Lean manufacturing is systematic elimination of wastes and removal of non-value added activities from the company's process. Wastes are considered to be loss of resources. There are eight types of waste targeted by lean methods which are defects, waiting, unnecessary processing, overproduction, movement, inventory, unused employee creativity and complexity. Companies choose to implement lean manufacturing to improve the product quality and to exceed customer expectation by reducing time required, resources used and capital to achieve them.

Companies involved in lean manufacturing undergo a paradigm shift from old 'batch and queue' mass production to product aligned 'one piece flow' pull production. In batch and queue mass production large quantity of goods are produced in advance depending upon customer requirements while in one piece flow the production activities are arranged in such a way that processing activities take place immediately adjacent to each other so that the flow is continuous. Common methods used in lean manufacturing are Kaizen; 5S; Total Productive Maintenance (TPM); Cellular Manufacturing; Just-in-Time Production; Six Sigma; which are also some of the manufacturing operations required by the firms to be world class and would be discussed later on. About one fourth of plants in US tried to implement the whole lean system. When companies implement several or all of these lean methods to gain world class status several outcomes consistently result like reduced inventory, decreased material usage, optimized equipment, increased production velocity, reduced complexity and enhanced production flexibility enabling the implementation of a pull production and just-in-time oriented system which lowers inventory and capital requirements.JIT delivery and low inventory are considered the primary element of lean system

This helps in creating continual improvement culture which is major priority for manufacturing company to achieve world class status so that they can increase profit, employee involvement, supply chain investment and competitiveness.