Lean Manufacturing - A manufacturing process model that seeks to avoid wasteful actions to optimize profitability of products and services while adding value from a customer's perspective.
Lean production is aimed at the elimination of waste in every area of production including customer relations, product design, supplier networks and factory management. Its goal is to incorporate less human effort, less inventory, less time to develop products, and less space to become highly responsive to customer demand while producing top quality products in the most efficient and economical manner possible.
Principles of Lean Manufacturing:
- Zero waiting time
- Zero Inventory
- Scheduling -- internal customer pull instead of push system
- Batch to Flow -- cut batch sizes
- Line Balancing
- Cut actual process times.
The characteristics of lean processes are:
- Single-piece production
- Repetitive order characteristics
- Just-In-Time materials/pull scheduling
- Short cycle times
- Quick changeover
- Continuous flow work cells
- Collocated machines, equipment,tools and people
- Compressed space
- Multi-skilled employees
- Empowered employees
- High first-pass yields with major reductions in defects
Lean Manufacturing incorporates the use of Heijunka, level sequential flow, Takt time, the heartbeat or pace of the production system, continuous flow manufacturing, cellular manufacturing, a
Lean is derived from the Toyota Production System and its key thrust is to increase the value-added work by eliminating waste and reducing incidental work. The technique often decreases the time between a customer order and shipment, and it is designed to radically improve profitability, customer satisfaction, throughput time, and employee morale.
See this example: The University of Kentucky Lean program From the site: The University of Kentucky lean program is the only program consisting of an academic and an industrial extension mission developed in partnership with the Toyota Motor Corporation.
Through this partnership, The Lean Systems team has been studying and learning the detailed workings of the Toyota Production System from the experts themselves.
The relationship requires the University to share what we have learned with others through education programs, academic research and industry service.
Many North American manufacturers, eager for instant results, try to steal the "quick fix" parts of lean and awkwardly force them into their existing plants to attack the enemy of lean: waste. Here's what the enemy, muda to the Japanese, looks like. (as described by the Massachusetts Institute of Technology.) The Toyota Production System defines seven types of waste:
- Overproduction: to produce more than demanded or produce it before it is needed. It is visible as storage of material. It is the result of producing to speculative demand;
- Inventory or Work In Process (WIP): is material between operations due to large lot production or processes with long cycle times;
- Transportation: does not add any value to the product. Instead of improving the transportation, it should be minimized or eliminated (e.g. forming cells);
- Processing waste: should be minimized by asking why a specific processing step is needed and why a specific product is produced. All unnecessary processing steps should be eliminated;
- Motion: of the workers, machines, and transport (e.g. due to the inappropriate location of tools and parts) is waste. Instead of automating wasted motion, the operation itself should be improved;
- Waiting: for a machine to process should be eliminated. The principle is to maximize the utilization/efficiency of the worker instead of maximizing the utilization of the machines;
- Making defective products: is pure waste. Prevent the occurrence of defects instead of finding and repairing defects.