Mura, Muri and Muda: Key Waste Management Concepts of Toyota Production Systems

Student name: Nemr MAROUNI IPM – 2011 1- Muda (無駄) is a traditional Japanese term for an activity that is wasteful and doesn't add value or is unproductive, etymologically none (無)+ trivia or un-useful (駄) in practice or others. It is also a key concept in the Toyota Production System (TPS) and is one of the three types of waste (Muda, Mura, Muri) that it identifies. Waste reduction is an effective way to increase profitability. Toyota merely picked up these three words beginning with the prefix mu-, which in Japan are widely recognized as a reference to a product improvement program or campaign. A process adds value by producing goods or providing a service that a customer will pay for. A process consumes resources and waste occurs when more resources are consumed than are necessary to produce the goods or provide the service that the customer actually wants. The attitudes and tools of the TPS heighten awareness and give whole new perspectives on identifying waste and therefore the unexploited opportunities associated with reducing waste. Muda has been given much greater attention as waste than the other two which means that whilst many Lean practitioners have learned to see muda they fail to see in the same prominence the wastes of mura (unevenness) and muri (overburden). Thus whilst they are focused on getting their process under control they do not give enough time to process improvement by redesign 2- Mura is avoided through Just In Time systems which are based on little or no inventory, by supplying the production process with the right part, at the right time, in the right amount, and first-in, first out component flow. Just in Time systems create a “pull system” in which each sub-process withdraws its needs from the preceding sub-processes, and ultimately from an outside supplier. When a preceding process does not receive a request or withdrawal it does not make more parts. This type of system is designed to maximize productivity by minimizing storage