In Part 2, I introduced the 1977 paper “Toyota Production System and Kanban System Materialization of Just-in-time and Respect-for-human System” written by the Production Control Group of the Toyota Motor Company. I also began a discussion as to why Toyota put as much emphasis on “Respect-for-human-system” as they did on the breakthrough concepts of “Kanban” and “Just-in-time”. My conclusion is that without this “respect for human” sub-system (and, yes, this is a system, not just some “feel-good” plugin), “Kanban” and “Just-in-time” will not work as designed within the Toyota Production “System”.
Here are some further excerpts from the 1977 paper that I think illustrate Toyota’s thinking on this point:
“The thing that corresponds to the second recognition of Japanese diligence, high degree of ability, and favoured labour environment is ” to make full use of the workers’ capabilities “. In short, treat the workers as human beings and with consideration. Build up a system that will allow the workers to display their full capabilities by themselves.” [quotes around ” to make full use of the workers’ capabilities ” are in original paper]
The first sentence is talking to the Japanese industry at large. The last sentence emphasizes that the “system” must be designed in such a way as to give workers the ability to act on their own. Flow and flow interruptions must be visible to them.
“…by checking the degree of inventory quantity and production lead time as policy variables, this production method discloses existence of surplus equipment and workers. This is the starting point to the second characteristic of Toyota Production System, that is, to make full use of the workers’ capability.”
This excerpt demonstrates how the system must work to give the workers the visibility to act on their own — by reducing inventory and lead times as much as possible.
“The reason why we consider inventory resulting from over-producing is the worst waste is that it hides the causes of waste that should be remedied such as unbalance between the workers and between the processes, troubles in various processes, workers’ idle time, surplus workers, excessive equipment capacity and insufficient preventive maintenance. Such latency of waste makes it difficult for workers to display their capability…”
Over-producing is the worst waste because it hides all the other wastes. Visibility is impaired.
“The reasons for’ Jidoka ‘ being so important: …Control of abnormality becomes easy. It will only be necessary to make improvements by directing attention to the stopped equipment and the worker who did the stopping. This is an important requirement when making up the system of ‘full utilization of workers’ capabilities’.” [internal quotes in original]
‘Jidoka’ creates the visibility of flow interruptions which then requires action to take place, by the workers themselves, in real time. Jidoka is one of the two pillars of TPS and is also ”an important requirement when making up the system of ‘full utilization of workers’ capabilities’.”
“Full utilization of workers’ capabilities: This is Toyota’s second basic concept of making the best use of Japan’s favoured labour environment and excellent workers. It has built up a system of respect for human, putting emphasis on the points as follows: (1) elimination of waste movements by workers; (2) consideration for workers’ safety; and (3) self-display of workers’ capabilities by entrusting them with greater responsibility and authority.”
“Toyota firmly believes that making up a system where the capable Japanese workers can actively participate in running and improving their workshops and be able to fully display their capabilities would be foundation of human respect environment of the highest order.”
Once again, the system must be designed to provide the worker the responsibility and authority to actively participate in running and improving their production areas.
“Any employee at Toyota has a right to make an improvement on the waste he has found.
In the just-in-time production, all processes and all shops are kept in the state where they have no surplus so that if trouble is left, unattended, the line will immediately stop running and will affect the entire plant. The necessity for improvement can be easily understood by anyone.”
With ”no surplus”, flow and flow interruptions can be seen, worked on and improved by everyone – immediately.
“Therefore, Toyota is endeavouring to make up a working place where not only the managers and foremen but also all workers can detect trouble. This is called ‘visible control’. Through visible control, all workers are taking positive steps to improve a lot of waste they have found. And the authority and responsibility for running and improving the workshop have been delegated to the workers themselves, which is the most distinctive feature of Toyota’s respect for human system.”
This says it all! Through creating maximum visibility (by removing inventory and reducing lead times), the “system” allows the workers (actually it depends on the workers) to run and improve the workplace on their own. “The authority and responsibility for running and improving the workshop have been delegated to the workers themselves”.
The “Factory Physics” group correctly states that there are only three buffers that can be used to balance a production system: Time, Inventory and Capacity. With a Time buffer – the customer waits. With an Inventory buffer – parts wait (actually it is cash that waits). With a Capacity buffer – machines and workers wait. “Factory Physics” advocates balancing buffers between the three types depending on each unique situation.
But in the Toyota Production System, time and inventory buffers must be reduced to the bare minimum. Both buffer types interrupt flow. Therefore, both are waste. While the concept of inventory as waste is familiar to all Lean practitioners, time as waste is tragically little known or understood. But remember, time is a non-renewable resource. Time is one of the three original factors of production.
“Time waste differs from material waste because there can be no salvage.”
“The easiest of all wastes, and the hardest to correct, is the waste of time.”
– Henry Ford
But by removing time and inventory waste you can increase effective capacity. Remember Ohno’s equation?
Present capacity = Waste + Work
Eliminate waste and that leaves additional capacity in place to do useful work. The beauty of the Toyota Production System is that it converts time and inventory buffers into a capacity buffer. Elimination of time waste and inventory waste leaves us with excess capacity. And capacity buffers do not interrupt flow. But if an interruption of flow does occur, there is adequate capacity available to correct the problem. At that critical time, useful work is done to the system rather than by the system.
The “respect for humanity system” is self-corrective in real-time. Ingenious!
(Note: Toyota’s version of a capacity buffer does not rely on having extra equipment or headcount. Toyota uses overtime if problems arise that need fixing. They build this into their shift structures in various ways).
Thus there is no “them” in real Lean/TPS – only “us”. And the “us” includes (1) those whose job it is to create and manage the system. And that system allows (2) those, who can now see the system flow, to do the value adding work – by both creating the value and eliminating the waste (kaizen). And the better the system is designed and managed, the more overlap there will be between (1) and (2).
“Many people believe that when implementing a new system, only know-how is required, however, if you want to succeed, you must understand know-why as well” – Shingo
And there is a lot of “know-why” in this 1977 Toyota paper!
And thus the sub-title of this blog.