7 wastes - introduction

In Japanese, "Muda" is meaning waste. There are 7 kinds of waste targeted by the lean manufacturing. From here, I will summarize them and give some possible solutions or methods to eliminate those non-value-add process. Before reading this post, we should have enough knowledge of value-added and non-value-added concept, refer to the VA & NVA 1 and VA & NVA 2.

1. Over-production; takt time concept is not considered in the case so they produce more than demand. From lean concept, this is the top waste of a company, takt time studing and JIT can solve this problem.

2. Motion; process is not good design so that operator will waste more time to handling the process. The operator needs to move or turn himself around and around to handling the process. We always use brain-stroming in Kaizen event to improve the work station process.

3. Waiting; because process flow is not balanced, too many motion in last process but waiting in next process. We need to record the process cycle in all process and well balancing in takt time analysis.

4. Conveyance; it means the WIP move a long way to next station, but it is totally not necessary. Re-design the process layout by 2P event is a effective way to solve the problem.

5. Processing Itself; the process station is not design or choose in the best way. As we knew, it always has many methods to produce the same product, the best way is also use brain-stroming in Kaizen event to choose the best method.

6. Inventory (raw material); because production plan issue or the cooperation of supplier, we have too many raw material inventory. At this moment, lean suppy chain and JIT are the ways to solve the problem.

7. Correction (rework & scrap); if the product or WIP is not made in good quality, rework or scrap is the only way to correct them. In lean concept, we need to make it good at once. For this waste, we need to choose the suitable tools to solve the problem in different causes. TPM is the most important factor in this case.

For 7 kinds of waste, they affected the productivity, cash flow and ontime delivery. Those factors are the root of NVA process or material flow. As my experiance, lean manufacturing concept is a best way to eliminate them. Offcause, use lean manufacturing tools skillfully is a very important element for improvement.