The starting concept of the Toyota productions system was, as I have emphasized several times, a thorough elimination of waste.
( Taiichi Ohno, Toyota Production System: Beyond Large Scale Production in Preface to the English Edition p.xiv)
The Toyota production system is a method to thoroughly eliminate waste and enhance productivity. In production, ‘waste’ refers to all elements of production that only increase cost without adding value .(Taiichi Ohno, Toyota Production System: Beyond Large Scale Production p.54)
The Waste of Overproduction.
Overproduction is producing more of something than is required. Producing more than is required means producing too much, or producing too soon or both. This results in poor flow with goods being pushed out rather than being pulled in.
The Waste of Unnecessary Motion.
Unnecessary motions refer to the importance of ergonomics for quality and productivity. If operators have to stretch, bend, pick-up, move in order to see better, or in any way unduly exert themselves, the victim is immediately the operator but ultimately quality and productivity.
The Waste of Unnecessary Inventory.
Parts, raw materials, work-in-process, inventory, supplies, and finished goods are all forms of inventory. Inventory is considered muda since it does not add value to the product.
Processing muda consists of additional steps or activities in the manufacturing process. Conducting the work using inappropriate tools, methods, procedures or systems typically result in a waste of time or the production of defects. This is often a function of increasing complexity requiring a simplification of the process or a reduction in the variety of tools.
All forms of transportation are muda. This includes the use of forklifts, conveyors, pallet movers, and trucks. Excessive movement of information, materials, goods, products or people results in wasted time and effort and increases costs.
The muda of waiting occurs when an operator is ready for the next operation, but must remain idle. Periods of inactivity for information, goods or people resulting in poor flow and long lead times.
The Waste of Defects.
The last, but not least, of Ohno’s wastes is the waste of defects. Any error or variation from a standard in the production of a product, in the delivery of service or in the processing of paperwork or information is a defect. Costs associated with defects include the costs of detection or testing, reprocessing costs or cost of scrapping should reprocessing prove impossible as well as warranty costs and the costs associated with dissatisfied customers.
This course provides a comprehensive overview of Lean Enterprise tools and methods, which may be used to supplement a Six Sigma curriculum.
Lean topics include value stream mapping, continuous flow, takt time, kaizen, line balancing, quick changeover, pull systems, and 5-S, among others. Read More