The roasting conditions of herbal medicines have been determined by the past experience and they are not necessarily optimum. There is a large variation on the moisture content of roasted herbs, and the roasted condition has been determined by the visual observation of operators. Parameter design was conducted to reduce variation. In the past, many experiments were conducted spending a large amount of raw materials and man power in order to set up roasting conditions. A small scale experimental equipment was devised and an orthogonal array was used in the experiment. From the results of experiment, conclusions from a small scale experimentation were well reproduced, revealed the possibility of success in scaling up.

This paper reports the stabilization of the flow of a carburetor starter system using Taguchi methods. The flow of fuel sucked by air in the carburetor was measured using a bench stand, and the parameters of carburetor were optimized. In the study, two analyses were compared: the case when starter plunger opening was considered as an indicative factor, and the case when starter plunger opening and sucked airflow were used as a double signal factor. By the use of Taguchi methods, the dispersion caused by fuel level and airflow changes was reduced to two thirds without cost increase. Also the optimum condition could be estimated from 18 experimental runs instead of running a total of 4374 runs. The time for analysis and determination of parameter conditions was reduced.

Reduction of chemical usage in semiconductor manufacturing has been discussed in recent years. In particular, the impact of global warming has been the focus of intense speculation. The low efficiency of chemicals leads to undesirable side effects. The aims of this study are to optimize plasma efficiency as chemical reactions using Taguchi method. In short, the plasma cleaning function is that residual oxidized film (SiO2) inside the chamber reacts with C2 F6,and it discharges the results of the reaction in the form of SiF4 and CO. The main point of optimization was to use F to increase the amount of desirable main reaction SiF4 and decrease the amount of unreacted C2F6 in order to keep the undesirable side reaction to a minimum. As the results, we found the CVD cleaning condition that improves plasma efficiency to 2 times, PFC gas usage to one third, PFC gas emission to one forth.

This is a study of applying On-Line quality engineering methods to improve the calibration of a measuring system to be used for pollution control. The optimum calibrating conditions were determined by balancing the loss due to quality with the costs of checking and adjusting. As a result, it was found that the calibration of a measuring system for drainage could be improved. It was also found that the measuring cost could be reduced while quality is maintained.

The measuring devices of copier and printer supplies are checked and calibrated following the procedures given by part of manufacturers. In this report, a study to improve the efficiency of managing these measuring devices was conducted by reviewing the checking frequency and calibrating limit based on JIS Z9000 (General Rules for Measurement and Calibration). For the toner softening point measuring device, the economic benefit after optimizing the checking and calibrating method was estimated. Then measuring error of the device was analyzed. From the results of study, the total loss was greatly reduced by optimizing the checking interval and calibrating limit. The measuring error was also reduced by reviewing the control limits of measuring conditions.

Quality Engineering known as Taguchi methods is a series of knowledge/methodology widely applied all over the world, especially in the U.S. This report describes another application of "On-line Quality Engineering". For the application of quality control to machining lines, we have extended the activities applied to "a transmission case machining line," which was reported last year, to the whole production line. The results of activities showed that by the adjustment of sampling interval based on process stability and the adjustment of cutting tool/equipment, the stability of product quality was drastically improved, including the reduction of inspection work load and the number of defective products. For the application to the production engineering system,the study of cycle time was carried out. We pursued the essence of the loss function from the standpoint of production engineering. From the actual data, it was found that there is linear relationship between cycle time and the loss. It was also verified that the slope of linear relationship varies depending on the component parts and different production lines. Based on the above results, a new guideline was set for cycle time setting, which was traditionally determined by experience or from fragmentary evaluations. There will be a potential of drastic reduction in the losses.

Stabilization of a production process through parameter design during daily pre-production calibration was studied. Cost and production plans normally make it difficult to perform experiments in the production process, which in this case involved the injection of a viscous liquid, but an experiment was planned and completed in the equipment adjustment process, and was successfully transferred to actual production. As a result, the defect rate was reduced from 1.67% to 0.012% in daily production, utilization of the liquid material rose from 88% to 97.5%, and it was demonstrated that with a change of timing and approach, experiments can be performed without expense, even in an environment unsympathetic to quality engineering.

Along with the improvement on the functions of electronics products, there is a trend that the amount of heat generated in CPU is increasing. Sillce there is a limitation in cooling capacity using traditional CPU systems, the improvement of cooling capacity is the key to the development of future products such as personal computers. Studies have been conducted in the past using a large scale experimental devices and using characteristics such as temperature, pressure or velocity that are hard to measure. Therefore, not too much successful evaluation was made despite its high cost and long period of time for development. The lmpingement Jet Stream, which was considered to be better than axialflow fan, was studied as a new cooling system. A simple experimental equipment was devised for the study based on the generic function of the system. After optimization, the variability due to environmental changes was significantly reduced, cooling efficiency was improved 4.9 times and the cost of experimental device was greatly reduced too.