Article ID: 0191002a
Tolerance is defined as “the difference between the maximum and minimum dimensions that can be allowed in terms of product functionality.” Company A, a steel manufacturer, follows the textbooks in presetting and managing tolerances so that its processes can flow seamlessly without any adjustments, as long as conditions remain within the range of tolerance. However, tolerance stack-up risk has been observed in the production of high-grade products such as automotive steel sheets because the quality measurements have approached the tolerance limits in several consecutive processes even though the said measurements have stayed within the tolerance range (which means that the products are not classified as defective). On the other hand, Company B (also a steel manufacturer) has been successful in managing tolerance through a method that is entirely different from the textbook model by having its Integrated Quality Control Group adjust the tolerances between processes and adopting strict controls that almost amount to integrated management.
ABAS is supported by Grant-in-Aid for Publication of Scientific Research Results from the Japan Society for the Promotion of Science.