Section 4. Plant Construction and Expansion

Item 4. Development and Deployment of the Toyota Production System

The Toyota Production System (TPS) is based on two core concepts. The first is the Just-in-Time system, and the second is jidoka, which can be loosely translated as "automation with a human touch." These two concepts were discussed above in Part 1.

In order to establish mass production systems, it was necessary not only to steadily increase production facilities, but also to streamline production control as well.

In order to establish mass production systems, it was necessary not only to steadily increase production facilities, but also to streamline production control as well.

TPS was steadily established and took root through the introduction of kanban to the existing supermarket style of production in order to reinforce the efficient Just-in-Time production system.1

The kanban, a tool that describes which and how many parts are used where and when, made just-in-time production possible. The new kanban management system was adopted at all plants in 1963. By producing parts in accordance with the instructions on the kanban, parts are delivered among the different plants only in the volumes needed, and inventories within each process can be eliminated. As kanban came into widespread use, problems such as standardization of work and transport management were resolved one after another and production lines operated smoothly.

Through 1965 kanban were also adopted for retrieving parts from suppliers. Toyota explained to suppliers that if they adopted the same techniques as Toyota, they could improve their operations, and companies that wished to do so steadily introduced TPS. This cooperation resulted in improvements, and TPS became established as an effective means of producing mutual benefit for both Toyota and suppliers.

To prevent individual processes from being burdened by excess personnel or equipment, production items and production volumes were equalized, that is, production leveling was also implemented. As a result of achieving level production from assembly lines to the retrieval of materials, the Just-in-Time system could be implemented on an even higher level.

If automatic shutdown devices are attached to machines to automatically stop the machines from operating when abnormalities are detected, the waste of unknowingly producing defective parts can be eliminated. This is jidoka of machinery. A further advancement is "management that can be seen with the eyes." Problem notification devices known as andon boards and andon lights are installed on each line in positions that are highly visible to supervisors, and when a problem occurs, andon are lit up-either manually or automatically so a supervisor can immediately come to the source of the problem and address it. Andon were installed in the Kamigo Plant in 1966, completing line automation with a human touch.

In 1966, an online control system was installed at the Takaoka Plant, making it possible to obtain production instruction information from terminals installed along the line and perform assembly work. The same system was also installed at the Motomachi Plant in 1969 and the new Tsutsumi Plant in 1970 in response to the rapid increase in production volumes and the expansion of vehicle specifications. However, because production instruction information could be retrieved from individual terminals, which allowed down-stream processes to be conducted before they were necessary, the system led to problems, including the occurrence of numerous assembly errors.

To address these problems, issuing production instructions from the terminals was terminated and a method of giving production instructions using sheets attached to the vehicle bodies was adopted. Production instruction information was obtained from the target of the work itself, and as a result, advance work assembly errors were eliminated and it was possible to respond flexibly to changes.

Responding precisely to changes in production volumes required an increase in availability rates (the percentage of time that facilities can be operated when operation is desired), and this meant raising equipment reliability. Accordingly, measures to raise the availability rates of equipment used in key processes were implemented. For example, at the Kamigo Plant, personnel from the plant and Production Engineering Division I formed a countermeasures team to rapidly detect problems and reinforce daily and periodic inspections on the machining and assembly lines for the T series engine. The team implemented measures from a variety of perspectives, including processes and equipment, and achieved a substantial improvement in availability rates.

As a result of the advancing of jidoka and other approaches that came along with the shift to mass production, a problem surfaced in which a fixed number of workers were needed to operate the equipment, even if production demand decreased substantially. Having experienced significant decreases in production demand, Toyota eliminated fixed staff systems to create production lines that could operate with a small number of workers, in case production demand dropped, and, through optimal placement of workers, sought to increase the added value of each worker. Former Vice President Taiichi Ono, who strived to revive Japan's automotive industry after World War II and who implemented streamlining of production and established TPS centered on the principles of Just-in-Time and jidoka, made the following the comments:

Calls for 'labor-saving measures' started from around 1960 and 1961, but I had always believed that it was necessary to implement 'people-saving' measures that reduced the number of workers needed.

Around the time of the oil crisis, I happened to give a lecture on labor saving, and later, looking at a summary of the lecture, the term 'personnel reduction' had been used instead of 'labor saving'. I realized that someone had hit the point, and I came to believe that personnel reduction was what would be needed from here on out.

Since production volume was going to decrease, it was necessary to perform production that had been conducted by seven workers with just six or even five workers. In other words, it was necessary to create and innovate facilities and equipment that could be operated by a small number of workers and manufacture products when production volumes decrease.

To top of page