In this study, the improvement of small DC motors used in automobiles was made through the evaluation of functionality. The functionality was evaluated by the relationship between the input power and consumed power. It was con sidered ideal that the power required can be obtained from the minimum power input. The power consumption during idle time was also studied. After the improvement of functionality, vibration and audible noise level were also significantly improved. Also by utilizing part of the gain of functionality improvement for the downsizing of motors, the cost and weight of motors were reduced. It is believed that the approach used in this study to evaluate the functionality of DC motors can be applied for the development of other motors towards the reduction of overall product development cost.

The plastic bumpers used in automobiles are painted by the spraying process. The process is widely used because its simplicity. However, it is difficult to maintain the uniformity in sprayed layer thickness, since the process is affected by air flow and the shape of component parts to be painted. For good appearance, the uniformity of sprayed thickness is important. In this study, quality engineering was applied to find the conditions to obtain the uniformity of sprayed film thickness throughout the whole bumper. In the experiment, the number of spraying times as the input and the thickness of sprayed film as the output were considered to establish the generic function. Zero-point proportional equation was used in the calculation. The shape of bumpers was used as the noise factor. As a result, it was succeeded to obtain a better spraying condition where both the S/N ratio and sensitivity were improved.

Among different types of air cleaners that collect the dust in the air, there is one called electrostatic precipitator which uses static power. To develop this type of collector, parameter design was conducted to find the best conditions for materials and the electrode structure. For the generic function, the reducing speed of the amount of dust in a closed space was observed. In this study, the SN ratio was calculated based on an equation that is used in chemical reactions. The conclusion had a good reproducibility, and the equipment was successfully developed in a short period of time at a low cost.

Thermal paper is used for a variety of products such as labels, facsimiles, word processors, printers, electric black board printers, handy terminals, etc. Label paper consists of base paper ,under-coating layer, thermal layer (heat sensitive layer), over-coating layer and back-coating layer. The thermal layer which per forms the main function of thermal paper consists of dyes, coloring agents, resins and surface-active agents. It is formed by mixing the suspensions of dyes and coloring agents. The mixture is adjusted, coated then dried. Dye particles can be further milled to be more color sensitive. But super sensitive particles create fog on the non-printed areas. Therefore, the particles must have a certain smaller average diameter and a narrow size distribution. Evaluation of the generic function was made as follows. Dye particles collide with beads, agitator and container wall, becoming finer particles. So the input/output relationship of energy was considered as the generic function. The input energy is proportional to time, and the output (work) is proportional to the surface area per unit weight. Zero-point proportional equation was used. In other words, milling time was considered as the signal factor. No noise factors were assigned. Analysis was also made using dynamic operating window (speed difference method). From the study of the former case, both SN ratio and sensitivity were improved. But the latter case resulted in a poor reproducibility.

Animals parameter design was conducted to prove the validity on the mixing ratios of herbal medicines which consists of multiple kinds of herbs. Mixing ratios were assigned to an orthogonal array. The variability of drug and its efficacy were evaluated by SN ratio and sensitivity, respectively. Comparison was made between current and optimum conditions. The individual difference in the seriousness of sickness between animals was considered as the noise factor. Variability was controlled by the use of SN ratio, As a result, the mixing ratio under the optimum condition was extremely effective compared with the worst among the 18 mixing conditions. It was also confirmed that the efficacy of the mixing ratio reported in the literatures bears comparison with the optimum one.

This report is an example of technology development on the material of jigs used in the manufacturing of wet-type clutch discs. Although this development was not successful as a result, but we have learned about "What is Quality Engineering?" One of the benefits from the use of Quality Engineering is to realize "The development has failed" as early as possible. We believe that such kind of report is worth while for publishing.