This study is an example of designing a developing device used for copying machines or printers. optimization was separately performed for initial phase and mid/late phase of development with different functionality. It is difficult at the early phase of development to start the design of the whole system, because at that stage, the function of the whole system was not satisfactory yet. Therefore, the whole system was subdivided into a few sub-systems and developed a small scale using test pieces. In the mid/late phase of development when the completion of the whole system was improved, an overall design was conducted After the use of this approach, the situation of having problems in the mid/late phase of development followed by going back to the initial phase design which has never occurred. Thus, the designing efficiency was greatly improved. The philosophy is to secure the achievement of downstream reproducibility,which is stressed in quality engineering. We believe that this is a universally applicable method for product designs, not only for the design of copy machines or printers but for all complicated systems. It is especially useful when there are many stages in development.

By using the MT system, we measured product usability, which is said to be difficult to perform, we quantified the contribution ratio of each design parameter to usability, and then we designed the parameter for the optimum usability. The usability of an operating lever for a receipt printer was optimized. The product that was optimized was examined by both calculation of the MT system and test subjects of the real sample. In both tests, extremely desirable results were obtained. To minimize the burden on the test subjects, the number of the test samples was small, resulting in multicollinearity in the calculation. However, a unique measure was taken to obtain the preferred result. As a result of this examination, the optimal usability was ensured even with a small number of parts, and furthermore cost reduction was realized. In the future,this method can be widely applied as a method to design a product and obtain the optimal usability.

In the automobile industry, steel component parts are required to have high strength, light weight and high quality. It is important to reduce the variability of the quality characteristics of these products during the manufacturing processes, especially in the forging process. To reduce the variability of the process, an experiment was conducted and results were summarized as follows:(1)In order to evaluate the strength of the products, it is necessary to study through the evaluation by the Hooke's law and transformability. (2)The magnitude of useless energy calculated from the study of transformability was 250 times of the one calculated from the Hooke's law. (3)Among the forging process,there is more room for improvement in the shot blasting process. (4)The gain in S/N ratio was 7.2db under the optimum condition. (5)The gain calculated from the loss function was 278 million yen per year.

We use casting simulation to examine gating schemes etc. at early stages of mold design. Afterward, we compare the analytical results with defects of actual cast products, then revise the analysis conditions to improve the precision of the analysis. Increased analytic precision, however, fails to reduce variations in casting quality. In this study, we used a test piece to attempt to optimize a magnesium die-casting plan for thin-walled castings, which are in increasing demand recently, As characteristic values, distance (position) was used as input, and the time taken from completion of filling of the melt to solidification of the melt was used as output. The analysis was performed using the standard S/N ratio, and repeatability was confirmed by gain estimation and confirmation. Tuning was also observed, though to a slight degree. The effectiveness of the combined use of simulation and quality engineering was confirmed.

In the recent years, many corporations or institutions are voluntarily working on the reduction of industrial waste that is environmentally harmful, in order to conform to the ISO 14001 (Environmental Management System). Some laws regarding recycling have been put in force. Such activities are the roles of enterprises. Our company is manufacturing various molded resin products to be used as the component parts for automobiles. In the resin molding process, wastes such as sprue or runner which are not the intended products are generated. These wastes have been treated by the industrial waste processing companies or raw material manufacturer. Such treatment cost affects our material purchasing cost. The treatment of such wastes in our company could reduce the cost as well as solve the problem of the environmental issue. To reuse the wastes, the runner was crushed in a runner crusher and then mixed with virgin resin as the material for the molding machine. Parameter design was conducted for optimization. As a result, the crushing process was proved to be superior to the existing one.

Staking is a general term for a processing method that permanently fastens a number of parts together by deforming one or more of the parts. In this study, a functional evaluation was performed on mechanical and electrical characteristics of the staking of metal parts designed to be joined together by purely mechanical joints. A comparison was made of two staking shapes, the relative merits of which had been hard to determine by conventional methods that evaluated quality characteristics. As a result, it was confirmed that the functional method was able to evaluate the fastness of a staked part more effectively than the conventional method.