1.

論文

論文
米山, 猛 ; 香川, 博之 ; 山出, 洋司 ; 伊藤, 豊次 ; 稲城, 正高 ; 瀧野, 孔延 ; 楊, 青
出版情報: 精密工学会誌論文集 = Journal of the Japan Society for Precision Engineering. Supplement. Contributed papers.  71  pp.347-351,  2005-01-01.  精密工学会 = The Japan Society for Precision Engineering
URL: http://hdl.handle.net/2297/43208
概要: 冷却水路を内部に持つ射出成形金型を, スティール粉体レーザ焼結造形法を用いて作成した. 箱形の成形品を対象とし, コアコーナ部に水路を設けることで、コア表面の温度分布が均一化し、成形品のソリが, 通常の金型による成形品と比べて著しく低減した . コア側の水温をキャビティ側の水温よりも適切に低くすることによって, 成形品のソリを最小にすることができた. An injection mold with inside cooling water channels which are difficult to be made by conventional machining method has been fabricated by using selective laser sintering of steel powders. A box shape work piece has been applied as a test structure. By the cooling inside the corner of the core, the temperature difference in the core surface is reduced and then the dimension accuracy of the work piece is improved compared with the work piece injected in the conventional machined mold with outside cooling channels. The core surface temperature is directly controlled by the cooling water temperature and kept constant at the end of each shot. When the water temperature of the inside channel in the core is assigned properly lower than that of outside channel in the cavity, the warp of the periphery of the box became minimum. Although the heat conductivity of the sintered material is lower than that of mold steel, cooling effect and accuracy improvement are promoted by the combination of cooling channels near the mold surface and adequate cooling temperatures. 続きを見る
2.

論文

論文
米山, 猛 ; 香川, 博之 ; 伊藤, 強 ; 伊藤, 豊次 ; 岩根, 昭裕 ; 蔵本, 義彦 ; 西本, 清史 ; 楊, 青
出版情報: 精密工学会誌 = Journal of the Japan Society for Precision Engineering.  67  pp.1991-1995,  2001-01-01.  精密工学会 = The Japan Society for Precision Engineering
URL: http://hdl.handle.net/2297/41942
概要: An injection mold which has inside water cooling channels has been fabricated using selective laser sintering method.Box shape workpiece was chosen as a test piece in order to confirm the effect of the inside cooling channels. Cooling channels are constructed in the core to make the effective cooling and uniform temperature condition.The warp of the side surface of the product injected with high cooling core was copared with that molded in the low cooling core without inside water channels. The amount of the warp obtained with the high cooling core was the half of that with the low cooling core and constant from the initial shot numbers.The temperature difference between the top surface and the bottom part of the core was about 20°C in the high cooling core whereas it exceeds 50°C in the low cooling core.It was confirmed that the water cooling channel inside the core reduces the temperature difference in the core and improves the dimension accuracy of the workpiece. The fabrication of the inside cooling channels using selective sintering method is useful to obtain stable and accurate injection molding. 続きを見る
3.

論文

論文
米山, 猛 ; 香川, 博之 ; 阿部, 諭 ; 末廣, 栄覚
出版情報: 精密工学会誌 = Journal of the Japan Society for Precision Engineering.  73  pp.1046-1050,  2007-01-01.  精密工学会 = The Japan Society for Precision Engineering
URL: http://hdl.handle.net/2297/41943
概要: Effective cooling channels have been installed in the injection mold during the process of milling-combined laser metal sintering. In the case of molding a flat piece with multiple ribs, it is difficult to insert cooling channels between the ribs by conventional machining. Because the heat remains between the ribs, the piece shrinks after the molding to form a warp on the flat surface. Using milling-combined laser metal sintering, oval holes were fabricated between the ribs and they were connected in a spiral loop. The temperature around the ribs became uniform and the warp on the flat surface of the molded specimen reduced compared with that molded in the mold made by conventional method using milling and electro-discharge machining. Simulation of the mold temperature and the warp by commercial software showed the same tendency on the change of the warp with the mold type and the cooling temperature conditions. Therefore, the accuracy of the molded specimen is improved by inserting cooling channels in the mold where heat accumulates using a milling-combined laser metal sintering and the effect can be evaluated by a simulation. 続きを見る
4.

論文

論文
香川, 博之 ; 米山, 猛 ; 伊藤, 強 ; 伊藤, 豊次 ; 岩根, 昭裕 ; 稲城, 正高 ; 瀧野, 孔延 ; 楊, 青
出版情報: 精密工学会誌 = Journal of the Japan Society for Precision Engineering.  68  pp.1057-1061,  2002-01-01.  精密工学会 = The Japan Society for Precision Engineering
URL: http://hdl.handle.net/2297/42715
概要: An injection mold with inside cooling water channels which are difficult to be made by conventional machining method has been fabricated by using selective laser sintering of metal powders. By the cooling inside the corner of the core, the temperature difference in the mold is reduced and then the dimension accuracy of the work piece is improved compared with the work piece injected in the mold with outside cooling channels. When the water temperature of the inside channel in the core is assigned lower than that of outside channel in the cavity, the temperature distribution in the mold becomes more uniform and the dimension accuracy of the work piece has been further improved. After the experiment, the structure of the sintered mold and its thermal conductivity has been measured to consider on the relation with temperature distribution in the mold. In order to achieve the uniform temperature distribution in the mold, adequate channels location will be necessary in relation with the thermal conductivity of the mold. 続きを見る