Lean Manufacturing


Lean Manufacturing, or Lean Production, refers to a business concept wherein the goal is to minimize the amount of time and resources used in the manufacturing processes and other activities of an enterprise, with emphasis on eliminating all forms of wastage.  It is basically the fusion of various management philosophies  designed to make operations as efficient as possible. Business philosophies invoked by lean manufacturing include Just-in-Time (JIT) Manufacturing, Kaizen, Total Quality Management (TQM), Total Productive Maintenance (TPM), Cellular Manufacturing, and the like. The roots of lean manufacturing can be traced to Japan, or more specifically, Toyota.


Lean manufacturing operates on three principles: 1) that 'muda', or waste, is bad; 2) that the manufacturing processes must be closely tied to the market's requirements; and 3) that a company should be seen as a continuous and uniform whole that includes its customers and suppliers, a concept known as 'value stream'.   Lean manufacturing is not merely a tool - it is a way of life that all members of an organization must appreciate, and practice.


The basic elements of lean manufacturing are: 1) just-in-time, higher efficiency manufacturing through the principle of 'continuous product flow' (also known as 'single piece workflow' ); 2) continuous improvement of processes along the entire value chain, primarily in terms of quality and cost; and 3) setting up of multi-functional and multi-skilled teams at all levels to achieve its goals.  Lean manufacturing is, in essence, the 21st century's upgraded version of the 20th century's 'mass-production' philosophy.


Among these elements, the most eye-catching is perhaps the 'continuous product flow', which entails the redesign of the production floor such that a product is manufactured progressively from one workstation to another with minimal waiting time and handling operations between stations.  This may mean the dedication of an entire process line to a group of similar products, or a group of products that undergo similar processing. The equipment and worktables are arranged in a 'streamlined' lay-out that keeps production continuous and efficient. Such a manufacturing set-up is also known as 'cellular manufacturing'. Attention to machine maintenance, up-time, and utilization is also a 'must.' 


According to lean manufacturing, the following are forms of 'waste' and should be eliminated: 1) waiting; 2) staging of inventories; 3) transport of inventories; 4) overproduction; 5) overprocessing; 6) unnecessary motion; and 7) defective units.


By adopting a production floor that conforms to continuous product flow, these wastes can be reduced. Another technique is through the practice of 'customer pull', which means that only products that are immediately needed by the customer (or the next station) must be produced. Thus, a station needing inventories to process should be the one to 'pull in' these inventories from the previous station. 


Kaizen, or the Japanese concept of 'continuous improvement', is a major influence on lean manufacturing. This is why lean manufacturing promotes teamwork among multi-skilled, multifunctional individuals at all levels to effect the continuous achievement of process improvements toward zero non-moving inventories, zero downtimes, zero paper, zero defects, and zero delays all throughout the organization.  


Benefits realized by companies that implemented lean manufacturing include: 1) waste reduction, and therefore, production cost reduction; 2) shorter manufacturing cycle times; 3) lower manpower requirements; 4) minimal inventories; 5) higher equipment utilization and manufacturing capacity; 6) improved cash flow; 7) higher product quality and reliability; and 8) better customer service.  The profits of the company are, as expected, also increased because of these benefits.


See Also:   Cell Manufacturing Just-In-Time (JIT)TPMTQMKaizen6-Sigma5S Process




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