Muda means waste and refers to a wide range of non-value-adding activities; eliminating waste is the key to efficiency. When you look at the Toyota Production System (TPS), eliminating Muda waste is one of the main principles of the Just-in-Time system. Some things that are considered waste are unnecessary financing costs, storage costs and worthless stock of old items. Toyota divides Muda into seven categories:
- Transportation – increases risk of product being damaged, lost or delayed.
- Inventory – Outlay of capital that doesn’t immediately produce income.
- Motion – Damage inflicted through the production process.
- Waiting – Product sitting idle.
- Over-processing – Doing more work than is necessary.
- Over-production – Making more product than is required by the customer.
- Defects – Replacing faulty parts or products.
Processes consumes resources and naturally, waste can occur. The more resources that are used, the more opportunity exists for waste. The tools of Lean manufacturing and the TPS help focus on the elimination of Muda waste and create a heightened awareness. Understanding exactly what waste exists and where it is exists is crucial to any Lean manufacturing process. Even though products differ between manufacturing organizations, lean practitioners understand that the types of wastes are very similar.
Before you can stop waste in any operation, you should able to see it, recognize it as waste, identify who is responsible, and finally appreciate its size and magnitude. Waste that is not seen cannot be eliminated. When something is denied as waste, it also cannot be stopped. When you refuse to accept responsibility for the waste, then you will not eliminate it. Of course, when the waste is not measured, you will not be motivated to stop it. What is not measured, is not improved.
According to Taiichi Ohno, the creator of the Toyota Production System, there is one, straightforward goal of the system, which is the absolute elimination of waste. If clearly understood, this simple sentence carries all information required to grasp the essence of the lean philosophy.