品質工学
Online ISSN : 2189-9320
Print ISSN : 2189-633X
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18 巻 , 5 号
選択された号の論文の6件中1~6を表示しています
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開発と研究
  • 吉澤 正孝
    18 巻 (2010) 5 号 p. 30-43
    公開日: 2016/10/17
    ジャーナル フリー

    Genichi Taguchi has compared a technology strategy to a battle strategy. As a strategy of this type, quality engineering must be applied in the research and development stage before product development begins. Although strategic planning precedes the actual fighting and tactics of a battle, it is the concrete deployment of the strategy that determines the winer. How that deployment is managed is as important as the strategy itself to the success of research and development. The author believes that in quality engineering as well, management,of organizational deployment is critical and the criteria for the Taguchi Award should be taken as a point of reference. This report focuses on "development of human resources" in those criteria. A report on the activities of Hiroshi Yano and others in the Hiroshima area was analyzed and elements of success were extracted from conventional Japanese ways of propagating technology,such as knowledge transfer and the motivation of engineers.

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事例研究
  • 明吉 秀樹, 細木 靖之, 平林 猛男
    18 巻 (2010) 5 号 p. 44-50
    公開日: 2016/10/17
    ジャーナル フリー

    Diazo photosensitive paper has been a Ricoh product since the company was first founded. As part of its environmentally-conscious management policy, Ricoh has developed the world's first photosensitive paper with a base layer made entirely from neutral recycled paper, to reduce the environmental impact of the paper. The new paper also has improved storability, mitigating a defect of conventional acidic paper and showing that a reduced environmental impact can be combined with enhanced reliability. If diazo photosensitive paper is stored in a high-temperature, high-humidity environment for a long period of time before being used for copying, copy image contrast is degraded by a precoupling reaction. To obtain paper that would develop.clearly and give crisp copy images, the storability quality issue was addressed in an optimal design study. Three storage environment levels were used as a noise factor. Illumination energy M (transmittance, measured on a gray scale) was used as the input, and an initial condition N0 signal, which was obtained by measuring the developed image density with a Macbeth densitometer and converting the measured value to a reflectance value, was used as the output. The output was analyzed by the standard S/N ratio (1) and was also analyzed after omega conversion (2). The responses to illumination at one-fourth the standard intensity for four times the standard time, illumination at the standard intensity for the standard time, and illumination at four times the standard intensity for one-fourth the standard time were analyzed as nominal-is-best characteristics (3) and dynamic characteristics (4), and the results obtained by these analytical methods were compared.

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  • 馬場 達朗, 大内 義昭
    18 巻 (2010) 5 号 p. 51-58
    公開日: 2016/10/17
    ジャーナル フリー

    In medical ultrasonography, adjustment of Doppler velocity range and velocity offset has been a complex manual process. In this study an automatic adjustment function was developed and optimized. A hybrid control system that recognizes blood flow conditions and makes an optimal response according to each colldition was developed. As a result, the error rate was reduced to less than one third of the rate achieved by conventional methods (from 10% to about 3%). The new method was then optimized by quality engineering techniques. As a result, the tracking capability of the estimated velocity range was improved to a higher value than the target value (process capability 3: within ±25% of the true value). Complex manual operations were automated and estimation accuracy and response reached a level good enough for practical use. In conventional product development, a function is first checked with a prototype and much time is then spent evaluating and adjusting its performance. In this study, the prototype was simulated and evaluated automatically, based on quality engineering. Compared with conventional cut-and-try methods, the time required for optimization of adjustable parameters was shortened and the reliability of product performance was improved.

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  • 金築 利旺, 原田 真介, 桑原 修, 岩垂 邦秀, 矢野 宏
    18 巻 (2010) 5 号 p. 59-65
    公開日: 2016/10/17
    ジャーナル フリー

    Agricultural crops are grown in all countries of the world by cultivation methods suitable for their locations and economic circumstances. Most cultivation techniques represent cumulative wisdom, based on the country's climate and soil conditions, that has been handed down from the past. In Japan, these traditional cultivation techniques have been publicized and spread and they form the basis of most agriculture today, with local climate and soil conditions also being taken into consideration. A farming experiment, a type of experiment rarely found in quality engineering, was carried out by growing sweet potatoes in a field under different combinations of existing cultivation methods and conditions, and evaluating and analyzing the results. This was also a first experimental step toward the prediction of crop yield from observations of initial crop growth. The experiment continued for two years and the results showed that the optimal conditions were almost identical to the published cultivation conditions,although the confirmation experiment showed a remaining problem concerning the reproducibility of the gain.

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  • 中根 義満, 越田 耕平
    18 巻 (2010) 5 号 p. 66-72
    公開日: 2016/10/17
    ジャーナル フリー

    Curling of paper in a copy machine is detrimental to copy quality, and a large curl inflicts loss on the user by causing the copy to jam in the transport path downstream of the fuser. A study was made to evaluate the proportionality of a dynamic characteristic with the degree of curl of the paper entering the fuser as the input and the degree of curl correction as the paper passed through the fuser as the output. Environmental factors and other noise factors such as the type of paper were selected and combined according to the direction of curl to obtain an optimal set of conditions. A confirmation experiment using the optimal conditions showed good reproducibility of the gain of the S/N ratio. Product development was performed with design parameters based on the optimal conditions. The resulting improvement in the field, in comparison with a copy machine with the same configuration to which quality engineering had not been applied, nearly matched the confirmed improvement in the gain of the S/N ratio.

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  • 矢野 耕也, 早川 幸弘, 鴨下 隆志
    18 巻 (2010) 5 号 p. 73-80
    公開日: 2016/10/17
    ジャーナル フリー

    The Recognition-Taguchi(RT) method is useful because, as itcollects items into the two variables β(sensitivity) and η(signal-to-noise ratio), a pattern distance can be obtained even when the number of original data items is greater than the number of unit space data items n, and because the dimensional reduction yields a solution even when the true values are unknown. In this study, however,the concept of the calibrated error variance proposed by Dr. Taguchi was applied. An attempt was made to calculate a general scale similar to the distance obtained by the RT method from the variation/variance ratio by use of analysis of variance, without calculating distances. Results matching the results of the RT method were obtained. In addition, it became clear that because analysis of variance is used, there is no limit on the number of items,which constrains matrix calculations, and the data can be treated in the same way as in the RT method.

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