As the funcional formula used in simulation analysis does not include noise variables arisen at various cutomer's usage conditions, the variations around the level of all design parameters are used to represent noise effects for signal to noise ratio calculation.

Because of the robustness against all those noises variables, it would be robust against all customer's usage conditions including deterioration and wear as those affect design parameters.

That is the most important strategy in robust design presented at 8th ASI Taguchi Symposium in 1990 presented by OKI Electric Co. ltd.

This paper's object is to improve the measure SNR by introducing a new measure called standard SNR. The SNR uses output data of signal at normal condition as signal values instead of signall Level itself. The new method is illustrated by the OKI case study. The new method also applicable for hardware experimentcase.

Lenses are polished by the diamond particles contained in grindstones. This study reports the development of grindstones using the metal plating technique. Various factors that affect lens duality were analyzed. It was considered that the concentration (or density) of diamond particles is most important. It is necessary to further study the correlation between diamond particle density and the performance of lens. The diamond particle concentration in the metal plating bath was used as the input signal and the one in the grindstone was observed as the output to calculate the dynamic SN ratio. From the study, a better adjustability of diamond particle density in grindstones was achieved.

Due to the miniaturization absorbed in various industrial areas in recent years,it has been necessary to develop more appropriate technologies to meet the miniaturization requirements.

One method to obtain milliature metal parts is press manufacturing, that is regarded as a mass production process because of the good quality and high productivity that can be attained. Among the press process, deep drawing is said to be especially difficult, and particular technologies are required for each case. Mostly the development of these technologies is empirical and based on experience, making this step long and expensive. In this work, by using quality engineering methods, we proposed and developed a drawing process to meet requirements of high quality and low cost.

The POS system is normally connected with various input/output devices and are used under various conditions such as outdoors, kitchens or portable applications in contrast with the applications for indoor business equipment. Because of the connection to input/output devices, the robustness in the market is important. A card reader terminal was used to improve its robustness under severe applying conditions and also to study the way to evaluate the grounding.

In this paper, an application of the MTS method for the appearance inspection of quartz devices. Appearance was transformed by a CCD camera into image concentration. Good quality quartz devices were selected to form a base space. The items to be used to construct the base space were studied and then altered. It was concluded that the MTS method can be used for the appearance inspection of quartz devices.

Digital type VTR (here referred to as D-VHS) was developed for high quality recording and playing back of satellite broadcasting. In the development of our new D-VHS model, it was aimed to improve the stability of tape run in a special play back function. In the experiment, the actual time required for the tape to run was measured against the time the tape would ideally run. Parameter design was conducted and the optimum condition was determined. As a result, the variability of the tape run was improved by 2.4μm.

In the re-flow soldering process, appearance inspection has been traditionally conducted. To improve the process, the cause and effect relationship between appearance and the process conditions are studied. With the development of high density mouting parts manufacturing technology in recent years, the appearance test can not be adopted any more. In order to use a high density mounting part for a new model, the re-flow process was reviewed and optimized without using the appearance test.