品質工学
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20 巻 , 6 号
選択された号の論文の5件中1~5を表示しています
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事例研究
  • 橘 勇佑, 田頭 康範
    20 巻 (2012) 6 号 p. 38-44
    公開日: 2016/10/17
    ジャーナル フリー

    Research on electrical tools is aimed at making them smaller, lighter, and more powerful. In pursuit of these goals, the authors have worked on improving the performance of motors and optimizing their structural parts. A hedge trimmer,which is used to trim hedges and garden shrubs, is an electrical tool the performance and weight of which are largely determined by the cutting blades. In improving the blades, it has been customary to rely on the intuition and experience of leading tool manufacturers and designers. This time, the blade shape in a hedge trimmer was optimized with the goals of improved cutting performance and durability, and the further goal of a quantitative evaluation of cutting performance. Cutting performance was evaluated in terms of the standard S/N ratio by placing a static tension load on the blade and using the waveform of the energy applied to the blade. Blade evaluation, which had been a subjective air in the pas, was successfully quantified.

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  • 中島 尚登, 矢野 耕也, 長澤 薫子, 安部 一之, 横田 邦信, 上竹 慎一郎, 松平 浩, 伊藤 周二, 湯川 豊一, 高木 一郎
    20 巻 (2012) 6 号 p. 45-54
    公開日: 2016/10/17
    ジャーナル フリー

    Using Mahalanobis-Taguchi system, diagnosis procedure combination survey data from 2007 to 2009 was analyzed. The object was 80 medical university hospitals of the whole country. Unit space was made using the data of the examination item at 7 consecutive higher medical university hospitals for three years. Distance (D) was calculated by RT method. Multi RT method was used, and compression of pattern D was carried out about a 3-year change and general D was demanded. And an order change account was carried out in general D. This order serves as a reference for an index of the collective strength of each medical university hospital.

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  • 高澤 拓也, 前田 敏男, 天谷 浩一, 矢野 宏
    20 巻 (2012) 6 号 p. 55-64
    公開日: 2016/10/17
    ジャーナル フリー

    The main spindle is an essential part of a machine tool, and main spindle malfunctions strongly impact productivity. In particular, unexpected random failures and malfunctions are a critical issue. Being able to predict the time when a main spindle needs to be replaced by detecting in advance that it is nearing the end of its life or is about to fail would greatly improve the efficiency of production planning by the machine tool user and maintenance service by the machine tool manufacturer. The ultimate goal of this study is the development of a system that can predict the life of a spindle. The feasibility of this goal was studied using the MT system. This first report concerns the development of a system for detecting failures efficiently. A unit space was selected using the S/N ratio of the pre-shipment electric power consumption waveforms of spindles, and decisions were made by the RT method from characteristic quantities extracted from the electric power waveforms used for calculation of the S/N ratios. As a result, a difference in distance was found between the unit space and unknown data, indicating the possibility of developing a system that can efficiently detect failures and predict spindle life.

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  • 馬場 達朗, 大内 義昭
    20 巻 (2012) 6 号 p. 65-75
    公開日: 2016/10/17
    ジャーナル フリー

    Recently, medical ultrasonic diagnostic equipment with a Doppler auto-trace/auto-measure capability is being used in the field of cardiovascular and perinatal diagnosis. The equipment automatically traces the spectral Doppler envelope and measures indices of the blood-flow wavefbrm during each heart-beat. In this study, an automatic measuring system that automatically measures a diagnostic index of blood flow on the basis of diagnostic images was developed and optimized. Reductions ih both the length and variability of the procedures carried out by the user were achieved, and highly reliable measurements were obtained. An automatic measurement algorithm for blood flow into and out of the left ventricle, which had been difficult to measure automatically,was developed. Scores of 90% and higher were obtained, in comparison to 20% to 30% by conventional methods. Measurement accuracy and consistency also reached levels high enough for practical use. Quality engineering was used durinb system development by carrying out prototype simulation and automatic evaluation. Compared with conventional cut-and-try methods, less time was required for optimizing the adjustable parameters and the reliability of product performance was improved.

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  • 大塚 祐一, 上杉 一夫
    20 巻 (2012) 6 号 p. 76-83
    公開日: 2016/10/17
    ジャーナル フリー

    So far, industrial engineering (IE) and quality engineering (QE) have been used as independent improvement methodologies. Some manufacturing processes can be rationalized by use of either industrial engineering alone or quality engineering (inspection design) alone, but in other cases this is difficult. Especially in a production line including inspection processes, the major issue is how to optimize the entire line, including deciding which items should be inspected. This study focuses on the scale by which improvement is evaluated,and demonstrates that manufacturing processes can be rationalized by making use of the synergy effect of industrial engineering, which evaluates time, and quality engineering, which evaluates loss. The method introduced here can become a general-purpose rationalization methods (model) that links industrial engineering and quality engineering, and has the potential to be widely applied to rationalization of production lines including inspection processes. Further research and wider utilization of this method at many production sites are expected to lead to productivity improvement in manufacturing industries.

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