著者

山崎 悟 乾 正知

出版者

公益社団法人 精密工学会

雑誌

精密工学会学術講演会講演論文集 2010年度精密工学会春季大会

巻号頁・発行日

pp.103-104, 2010 (Released:2010-09-01)

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設計改善のための厚み評価方法を提案する。プラスチック部品の射出成形では,部品形状の厚みに不揃いがあると,成形時にヒケと呼ばれる歪を生じたり,湯が十分に回らない等の問題が生じやすい。これらを事前に回避するために,立体モデルの内部に球を配置することにより厚みを定義し,さらに立体モデルにおいて指定値よりも厚い部分を分類表示する技術を開発した。実際にプログラムを作成し計算実験を行うことで,本技術の有効性を検証した。

著者

蛯名 雄太郎 前崎 智博 周 立波 清水 淳 小貫 哲平 尾嶌 裕隆 乾 正知

出版者

公益社団法人 精密工学会

雑誌

精密工学会誌 (ISSN:09120289)

巻号頁・発行日

vol.84, no.7, pp.640-645, 2018-07-05 (Released:2018-07-05)

参考文献数

16

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The grinding wheel is comprised by three elements; abrasive grain, bonding material and pore, which are specified by five factors; type of abrasive grain, grain size, type of bonding material, grade of hardness and abrasive grain volume percentage. Regarding the abrasive grain, it is well known that shape and number of cutting edge significantly effects grinding performance such as surface roughness, grinding force and grinding wheel life. In general, abrasive grain size is determined by mean diameter of abrasive grain. However, the abrasive grains in a grinding wheel are randomly scraggly in size and shape. There is no particular aspect to regulate the grain size variation in JIS (Japanese Industrial Standards). This paper investigates the effect of grain size variation on the ground surface topography by actual grinding on silicon wafers and analysis based on grinding simulation. The results reveal that the standard deviation of grain size is a very important index to characterize the grinding performance of a wheel. Smaller standard deviation leads to larger density of effective cutting-edge under the same volume percentage of abrasive grain contained in the wheel. This fact significantly contributes to not only achieve a better surface roughness and more uniform surface integrity, but also shorten the finishing time.

著者

乾 正知 崔 原己

出版者

公益社団法人 精密工学会

雑誌

精密工学会誌 (ISSN:09120289)

巻号頁・発行日

vol.68, no.10, pp.1316-1320, 2002-10-05 (Released:2009-12-04)

参考文献数

8

被引用文献数

1

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Molds and dies are usually fabricated using 3-axis NC milling machines with a spherical cutter. In order to avoid gouging problems in the milling process, a tool reference surface representing the offset shape of the designed surface is computed prior to the cutter path generation. Inverse offset method is used in practice which approximates the tool reference surface as a set of dense points. These points are usually derived as an elevation map of uniform grid points on the xy-plane, therefore distance between the points on the near vertical surface often becomes larger than the acceptable value. Such grid based computation causes stair-case errors on the wall shape, which also deteriorate the surface quality. In this paper, the authors propose an improvement of the inverse offset method. Our method computes the points on the tool reference surface by using additional two grids on the yz-plane and zx-plane. Different from the conventional method, proposed method can control the distance between the points on the tool reference surface being smaller than a certain constant value. Most part of the computation in our method can be accelerated by using the hardware power of the polygon rendering LSI, which is already equipped in most PCs. An experimental program is implemented and some computations of the tool reference surfaces are demonstrated.