In this case study of the optimization of the disc clamping structure of an optical disc player, the generic functions were considered to be the relation between power consumption and rotational speed, which is a work quantity, and the relation between power consumption and time. Dust was taken as a noise factor, because the interiors of players in which the clamping mechanism fails due to excessive wear frequently show visible accumulations of dust, which is a factor causing wear. The key point in this study is the comparison of an evaluation by the S/N ratio with the results of lifb tests. When life tests were performed under the optimized conditions on actual equipment, it was confirmed that wear to the clamp mechanism was greatly reduced. The gains of the S/N ratio before and after the tests were found to be nearly identical, and the gain was reproduced in a confirmation test. A further result obtained was near-perfect agreement between the gain of the S/N ratio and the estimated life, showing the possibility of dispensing with repeated life tests and greatly reducing the number of man-hours of development work.

Simulation by computer-aided engineering has been used since the 1980s to shorten development time and reduce the cost of prototyping in automobile engine development. The results have improved the initial quality of components,reduced the amount of redesign, and improved the efficiency of the development process. However, making the development process more efficient is not enough; the manufacturer must also provide products that meet customer expectations and are robust under use by various types of customers in various market environments. In the present study, quality engineering was therefore applied in the early development phase, the piston oil retention function was optimized, and the effect was confirmed in a prototype.

Integrated software debugging methods using orthogonal arrays have become an in-house standard that is frequently applied, but the applications have been limited to the later stages of the design process, so a study was undertaken with the object of application to the entire software design process during in-house software development. The study began with the in-house standardization of the integrated debugging methodology, which was then applied to unit debugging using small orthogonal arrays, and applications were then expanded to include checking methods during the design process, working from down-stream to upstream in the design flow. The design flow was also reconsidered,the checking system and the points at which it was to be applied were studied,and improvements were implemented. Finally, the application of parameter design to software design was studied and a proposal was made. The generic function of software was defined as stable functioning and operation with a variety of settings in a variety of usage environments. After sigrial factors were assigned to an orthogonal array and debugging personnel were assigned as noise factors, debugging was carried out and the bugs that were found were evaluated. The following is an in-house case study report, including the results of a study of the effects obtained and further issues.

This study deals with a case in which a product and its production process equipment were developed concurrently, using the function of the product as a characteristic value fbr evaluating the process equipment. The equipment was plastic forming equipment for a light guide plate. The objectives were to improve performance by developing technology for the basic equipment, and to reduce investment in peripheral equipment. These objectives were achieved:the S/N ratio of the basic equipment was improved by approximately 14 db; as a result, peripheral equipment became unnecessary, and a highly productive process was designed.