This study is an application of the Mahalanobis-Taguchi system to boring diagnostic and evaluation. When applied to boring, Taguchi methods can predict the precision of finished products, diagnose problems, and predict cutting precision from electricity data. This study deals with finished product prediction and diagnosis of problems. To predict the precision of finished products, an analysis was performed with data obtained from a waveform analysis of electricity data from the first processing as a data item and the S/N ratio obtained through parameter design as a signal. As a result, a prediction system was obtained with a precision level of 5 to 6 db, depending on the way in which the unit space was determined. For diagnosis of problems, the possibility of diagnosis by the Recognition-Taguchi system was examined with damage to the cutting blade during the experiment as the problem, and 30 items of electricity data obtained by 3-second waveform analysis as the data item. It was shown that problem diagnosis is possible by setting a separate unit space and threshold value for each processing state.

Motors are often evaluated in terms of their electric power consumption and other electrical characteristics. In the reported literature on the evaluation of stepping motors, however, it is always the results of rotation of the motor that are measured. The authors carried out a stepping motor evaluation by using electric characteristics. The results showed the same trends as the defect rate in the field.

One method of testing tap water for residual chlorine uses a diethyl-p-phenylenediamine (DPD) reagent. The test is very simple, consisting of adding DPD to the water to be tested and measuring residual chlorine from changes in the absorption of light (coloration). A false positive reaction, however, is known to proceed under the influence of ultraviolet light, making the coloration more intense. Care must therefore be taken with regard to sunlight when the method is used outdoors. In the present study, parameter design was used to develop a chlorine test reagent with high light tolerance. The test system as considered as a measuring instrument with residual chlorine concentration as input, variation pressure distance of optical absorption as output, and the presence or absence of irradiation by ultraviolet light as an error factor. An effective test wavelength was also found through selection analysis.

From a study of the indenting deformation process test it became clear that there were large mutual interaction effects between the heat treatment conditions of the test piece and the test conditions, and that the strength of materials is determined by the combination of heat treatment conditions and test conditions. In the present study, a high hardness level tension deformation process test was carried out and its relation to the indentation deformation process test was studied. The meanings of the S/N ratio η and the sensitivity coefficients β₁ and β₂ were clarified, and the possibility was shown of being able to establish an all-purpose evaluation method for the strength of materials by considering the strength of materials as a deformation process and applying this to both tension tests and hardness tests.