Waste, in lean terms, is any activity that does not add value to the product while costing a manufacturer money and resources. From active losses to missed opportunities, these wastes are so common in manufacturing operations that they are often overlooked. The different types of waste can be identified by their symptoms, as defined by the late Taiichi Ohno, the chief engineer at Toyota who was the architect of the Toyota Production System.
The original seven wastes, or muda, are transportation, inventory, motion, waiting, overproduction, overprocessing and defects. These are often referred to by the acronym “TIMWOOD.” An eighth waste of underutilizing the talent or skills of workers was introduced in the 1990s when the Toyota Production System was adopted in the Western world. As a result, the eight wastes are commonly referred to as “TIMWOODS.”