In this article, we explain the Toyota Seven Wastes Examples – but focus on how each is related to the other.
It is astonishing how the principles in Taiichi Ohno’s seminal book “Toyota Production System: Beyond Large Scale Production” are so relevant today, probably even more so when the book was first published. Specifically, I want to highlight a key insight from Taiichi Ohno on the waste of Overproduction and Waiting.
All Wastes Are Not Equal
As a reminder, a key concept in Lean Manufacturing and The Toyota Production System is the notion of waste. Waste has a very formal definition and there are 7 types of wastes:
- Transportation
- Inventory
- Motion
- Waiting
- Overproduction
- Overprocessing
- Defects
From experience, each of the 7 wastes above have a symbiotic relationship to each other. Let me explain.
On page 59 of “Toyota Production System: Beyond Large Scale Production”, Taiichi Ohno says:
[W]e frequently see people working ahead. Instead of waiting, the worker works on the next job, so the waiting is hidden. If this situation is repeated, inventory begins to accumulate at the end of the production line or between lines. – page 59
Here, we see at least two types of waste at play: Waiting and Overproduction. Even more, how the desire to not stay idle, leads to motion, overproduction, and ultimately leading to more inventory than was needed. At the end of this chain, we find that there were 5 types of waste at play – each feeding the other.
But, what we also see is somewhat of a hierarchy in the 7 Wastes: waiting is less terrible than overproduction and overinventory. In other words, when we “hide the waiting”, then we create more waste – waste that can be even more costly to the organization.
Taiichi Ohno explains that the tendency to not wait, leads to the situation above:
We regard only work that is needed as real work, and define the rest as waste. . . . we must make only the amount needed. – page 19
But, we know from experience, that some people (I include myself in this indictment) move for the sake of movement; or work for the sake of working. But, as Ohno explains, unless there is a need for the effort, then it is waste and could potentially lead to making stuff people don’t want.
Taiicho Ohno continues,
I used to tell production workers one of my favorite stories about a boat rowed by eight men. One rower might feel he is stronger than the next and row twice as hard. This extra effort upsets the boat’s process and moves it off course. – page 24
If I could finish Taiichi Ohno’s line of thinking: And, getting the boat back on course would require even more work and effort than if all effort by the rowers were equal. In other words, overeffort in this context created more costly waste.
Conclusion
Taiichi Ohno’s teachings are more relevant than ever. His insight into the 7 Wastes and the relationship of each wastes to each other can guide us on how we manage our business.
It’s Your Turn
What have you observed? Do you find there to be a hierarchy in the Toyota 7 Wastes?
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AieaDragon says
Producing defective products appears to be the most significant “WASTE.” If there are no In-Process inspections and the defect is caught at the end of the process, all the WIP is questionable. When you find a defective product, the production line usually stops and put in a safe condition, the root cause needs to be troubleshooted and found, and the defect corrected and/or repaired or replaced due to normal/abnormal wear and tear, something broke, someone didn’t follow the established process, dirty environment, etc. Also, replacement parts may need to be procured (in Hawaii, we often fly in urgently needed parts). The Worst case senario would be if the defective products were REJECTED by the CUSTOMER!
Alberto Salvia Novella says
Quality assurance is usually waste itself, cause it’s just hiding that the process isn’t reliable by itself.