Section 4. Construction of the Automotive Department Assembly Plant and Koromo Plant
Item 7. Reforming and Improving Vehicle Quality
When a defect occurs in an automobile, it is necessary to quickly correct the problem, modify the design, and replace the original part. In order to minimize losses from disposing of the original parts, it is desirable to maintain small inventories and work in progress. Kiichiro Toyoda's goals in proposing Just-in-Time were to reduce inventories of parts between processes, cut the time needed for raising vehicle quality, and lower expenses.
When improvements were made to vehicles at the Toyoda Automatic Loom Works Kariya Plant, not only were substantial losses incurred from discarding inventories of parts, it took nearly one year for improvement proposals to be implemented. Even so, it was nearly impossible to supply the improved service parts. Kiichiro believed that the cause of these problems was the lack of a developed plant organization (production system). The Toyoda Automatic Loom Works plant carried out both loom and automobile production, but the priority was placed on manufacture of loom parts and automobile parts necessarily took a back seat.
The plant had large parts inventories because automobile parts were manufactured in batches when production was possible. As a result, when part designs were modified to make improvements, the inventories of existing parts had to be discarded, resulting in substantial losses.1 In addition, production of prototypes and commercialization took considerable time, and it took nearly an entire year before improvement proposals for design modifications could be implemented. Moreover, for each vehicle, 5 to 7 service parts with modified designs were necessary, but production could not be conducted in time, and it was nearly impossible to supply the parts.
Number of problems with Toyota vehicles of the time were pointed out: 1) engine overheating, 2) weak front springs, 3) differential gear susceptible to breaking, 4) strange noises produced by the transmission, 5) difficulty steering, and 6) Babbitt metal burning. Kiichiro planned to resolve all of these problems at once and produce new vehicles at the Koromo Plant.3
The new Model GB truck discussed below, however, also had a number of problems that needed to be addressed. Toyota Motor Co., Ltd. made numerous efforts including switching to internal manufacture of parts, modifying designs, and improving materials and manufacturing methods, and slowly the problems were eliminated.