Notes from Toyota Production System
The starting concept of the Toyota production system was … a thorough elimination of waste. In fact, the closer we came to this goal, the clearer became the picture of individual human beings with distinct personalities. There is no real substance to that abstract mass we call “the public.” We discovered that industry has to accept orders from each customer and make products that differ according to individual requirements.
All kinds of wastes occur when we try to produce the same product in large, homogeneous quantities. In the end, costs rise. It is much more economical to make each item one at a time. The former method is the Ford production system and the latter is the Toyota production system.
In the Japanese system, operators acquire a broad spectrum of production skills that I call manufacturing skills and participate in building up a total system in the production plant. In this way, the individual can find value in working.
Industrial society must develop the courage, or rather the common sense, to procure only what is needed when it is needed and in the amount needed. This requires what I call a revolution in consciousness, a change of attitude and viewpoint by business people.
|Functions of kanban||Rules of use|
|Provides pick-up or transport information||Later process picks up the number of items indicated by the kanban at the earlier process|
|Provides production information||Earlier process produces items in the quantity and sequence indicated by the kanban|
|Prevents overproduction and excessive transport||No items are made or transported without a kanban|
|Serves as a work order attached to goods||Always attach a kanban to the goods|
|Prevents defective products by identifying the process making the defectives||Defective products are not sent on to the subsequent process. The result is 100% defect-free goods|
|Reveals existing problems and maintains inventory control||Reducing the number of kanban increases their sensitivity|
In 1963, we started handling the delivery of the parts ordered from outside. It took nearly 20 years.
The Toyota production system is the production method and the kanban system is the way it is managed … Unless one completely grasps this method of doing work so that things will flow, it is impossible to go right into the kanban system when the time comes … Kanban is a tool for realizing just-in-time. For this tool to work fairly well, the production processes must be managed to flow as much as possible. Other important conditions are leveling production as much as possible and always working in accordance with standard work methods.
To ensure that we have 100 percent defect-free products, we must set up a system that automatically informs us if any process generates defective products; that is, a system in which the process generating defective products feels the pinch. …
If the meaning of “Defective” goes beyond defective parts to include defective work, then the meaning of “100 percent defect-free products” becomes clearer. In other words, insufficient standardization and rationalization creates waste (muda), inconsistency (mura), and unreasonableness (muri) in work procedures and work hours that eventually lead to the production of defective products.
Unless such defective work is reduced, it is difficult to assure an adequate supply for the later process to withdraw or to achieve the objective of producing as cheaply as possible. Efforts to thoroughly stabilize and rationalize the processes are the key to successful implementation of automation. Only with this foundation can production leveling be effective.
A business organization is like the human body. The human body contains autonomic nerves that work without regard to human wishes and motor nerves that react to human command to control muscles … e salivate when we see tasty food. It accelerates our heart rate during exercise …
At Toyota, we began to think about how to install an autonomic nervous system in our own rapidly growing business organization. In our production plant, an autonomic nerve means making judgments autonomously at the lowest possible level; for example, when to stop production, what sequence to follow in making parts, or when overtime is necessary to produce the required amount.
I believe I can safely recommend: “Correct a mistake immediately - to rush and not take time to correct a problem causes work loss later.” I also say, “Wait for the right opportunity.”
I like to point out that the slower but consistent tortoise causes less waste and is much more desirable than the speedy hare who races ahead and then stops occasionally to doze. The Toyota production system can be realized only when all the workers become tortoises.
To me, IE is not a partial production technology but rather a total manufacturing technology reaching the whole business organization. In other works, IE is a system and the Toyota production system may be regarded as Toyota-style IE.
We can talk about work improvement, but unless we know production thoroughly we can accomplish nothing. Stand on the production floor all day and watch - you will eventually discover what has to be done. I can emphasize this too much.
Opening our eyes and standing in the manufacturing plant, we really understand what waste is. We also discover ways to turn “moving” into “working”, activities that always concern us.
The Toyota system takes the reverse course. Our production slogan is “small lot sizes and quick setups.” Why are we so different from - in fact, the opposite of - the Ford system? … Complete elimination of waste is the basis of the Toyota production system.
“If we waste that bit of coal - which is another way of saying if we do not put it to its full value - then we waste the time and energy of men. A man cannot be paid much for producing something which is to be wasted. … We have a large salvage department, which apparently earns for us twenty or more million dollars a year … Why should we have so much to salvage? Are we not giving more attention to reclaiming than to not wasting?” – Henry Ford, Today and Tomorrow, “Learning from Waste”
“Industry exists to serve the public of which the working man is a part. The true end of industry is to liberate mind and body from the drudgery of existence by filling the world with well-made, low-priced products.”
We see that automation and the work-flow system invented and developed by Ford and his collaborators were never intended to cause workers to work harder and harder, to feel driven by their machines and alienated from their work.
The production management technique we call industrial engineering (IE) came from America. Traditional definitions aside, in the Toyota production system, IE is regarded as the production technology that attempts to reduce costs by harmonizing quality, quantity, and timing throughout the production area.