Lean manufacturing (lean production, or simply ‘lean’) is a management philosophy that employs the just-in-time manufacturing approach and focuses on waste elimination (or prevention) and reduced inventory, empowered workers and enhanced productivity. In other words, the products are made-to-order, which helps better efficiency and eliminate wastes. The management principle believes every aspect of production must offer value to the buyer – everything else remaining is waste. This helps differentiate lean manufacturing from just-in-time. Lean encompasses the entire organization; JIT only focuses on manufacturing.
Lean manufacturing ensures:
- Goods aren’t overproduced or are more than consumer demand
- Minimal to zero lag between different production stages
- Limited inventory
- Efficient transportation of materials
- Little to no rework
- Reduction in time spent on locating and addressing production errors
- Efficient use of workers and equipment
Identifying wastes, waste analysis and finding the root cause, and solving the base-level cause are the three primary stages of the lean manufacturing process. For waste reduction, management philosophies or tools such as JIT, kanban, zero defects, Single Minute Exchange of Die, error & mistake-proofing, two-bin inventory control, heijunka (level-loading), continuous improvement and the 5S philosophy. In reality, there are innumerable methods or ways to incorporate and implement lean manufacturing.
First developed by Taiichi Ohno, Toyota executive, during the reconstruction phase in Japan after the Second World War, the term was later popularized by Daniel T. Jones and James P. Womack in Lean Thinking – a book published in 1996. Mr. Ohno was so instrumental in developing the concept, he was later referred to as the ‘father of lean manufacturing’.
Though primarily designed to serve the manufacturing sector, lean thinking is also applicable to service-based firms or office environments. Moreover, lean is an ongoing journey or an evolving concept and never fully accomplished. Customer values change with time, and since the focus is on the buyer, lean principles will naturally evolve which manufacturers must adhere to or adopt. This is also the reason why there’s no universally accepted lean definition.
Lean production is strict adherence to customer requirements. But buyer needs can be ambiguous at times. Also, determining who exactly the customer is not always easy, since every stakeholder (including investors, society, etc.) expect something from the firm.
Involvement and co-operation of every employee, right from the CEO to the janitor, is crucial for lean production success. Besides voicing out opinions and giving suggestions, the entire workforce should agree with the management’s lean principles. As cost-cutting is pivotal to lean management, workers shouldn’t feel they’re being exploited or offered lower wages. Companies that don’t manage to solicit workforce involvement are likely to falter in implementing lean.