In Japan, an activity is associated with the 5S activity. They call it “O Tei” management. I put it as “O” because there is a number inside the “O.” The number changes depending on who you are talking to. I have seen “3 Tei,” “5 Tei,” and “6 Tei.” Let's review all of them to understand what they are trying to do.
First of all, the word “Tei【定】.” This symbol means to set, define, decide, or fix. This also implies rule or fate. It also means clear. So, this activity aims to determine the rules on these topics and make the problems more visual.
The six topics are:
1️⃣ Tei-i 【定位】; fixed location.
2️⃣ Tei-hin 【定品】; fixed thing.
3️⃣ Tei-ryou 【定量】; fixed volume.
4️⃣ Tei-ji 【定時】; fixed time.
5️⃣ Tei-kou 【定高】; fixed height.
6️⃣ Tei-hou 【定方】; fixed direction.
Let’s look at each of them and their connection with standardized work.
1️⃣ Tei-i 【定位】; fixed location.
The definition of where to place needs to be more precise. We should base the location on standardized work, not create obstacles and standardize detours. The location speaks a lot about how we think about human work. Standardized work will be easy and smooth if the locations are carefully designed. The location of things has to be human-work-centric.
There is another crucial fixed location called “fixed location stopping.” We should not stop the standardized work at random points. When we do this, we risk re-starting from the wrong element. Instead, we always stop at the end of the cycle and in the same position. By doing so, we always restart from the same standardized element.
2️⃣ Tei-hin 【定品】; fixed thing.
The definition of what is placed at the above location.
Since the standardized work determines the above location, the work contents decide what should be placed there. We don’t need every tool or multiple tools, just in case. If a case requires an additional tool, such as repair, that is already out of the standard, the problem should be taken care of by pulling the Andon. The idea here is not to make things look beautiful with many tools. The idea is to highlight a problem that prevents you from the best condition: standardized work.
Another problem is that they prefer flexible location systems with today’s storage technologies. They claim that since IT remembers all the locations, they don’t want fixed locations and items. They claim that they can “visualize” problems. Yet, I have not seen a case where they cared about over-production. As long as an item finds a space, people don’t care. And this creates another problem of under-production. The store might be full, but you may be missing a specific item you need now. A store with a fixed location & thing provides explicit notification of the status of your operations.
3️⃣ Tei-ryou 【定量】; fixed volume.
4️⃣ Tei-ji 【定時】; fixed time.
I included these two as a set since fixing both could become a “push” system rather than a “pull” system. If we deliver a fixed quantity at a fixed time, that is a push system.
Standardized work is designed based on one by one. Takt time is set for one unit. But if there is a problem, we can pull the Andon for support. In a mixed production, we can have designs with different cycle times. In such cases, we have to implement the leveling of production since the cycle time of each design is different.
In logistics, we will have either fixed volume, flexible time, or flexible volume, fixed time. A forklift delivers pallet by pallet, but the timing has to be flexible. A water spider or material train will run with fixed time, but what and quantity will depend on Kanban. We should do the 5S according to the system, depending on which system we choose.
What we should fix and keep as flexible between volume and time depends on the system design.
5️⃣ Tei-kou 【定高】; fixed height.
We should define the maximum and minimum height allowed.
The first reason is safety. Too much vertical movement is not safe from an ergonomic point of view. The second reason is that Japan lives on top of the earthquake. Loading materials too high exposes people to the risk of collapsing.
The other reason is visibility. Highly loaded material is the same as a “wall.” A “wall” could become a psychological barrier between people and departments. “Oobeya” means to locate people without a “physical wall.” We should prevent the creation of such a “wall” in production by limiting how high we allow the material to rise.
6️⃣ Tei-hou 【定方】; fixed direction.
The final one is defining the direction of the material. This might sound like a small thing, but it is still vital. When materials come in various directions, the worker has to orient the direction, which becomes a fluctuation. Sometimes, the worker placed the part in the wrong direction, and after getting confused by multiple directions, the material was supplied. In other cases, undefined directions caused the material to have harmful friction, causing defects. From the point of view of quality and efficiency, we should have a standard direction.
This 6 “Tei” management is not as popular as 5S because it doesn’t have a clear definition. However, it does provide some thoughts on standardization. What should we fix, and what should we keep it flexible?