Papers by Author: Keiji Ogawa

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Authors: Keiji Ogawa, Hirotaka Tanabe, Heisaburo Nakagawa
Abstract: This paper proposes a novel process strategy for micro-cutting edge fabrication. Micro-cutting edges need a hardening process for the ridgeline parts that requires abrasive resistance, as well as edge sharpness and shape accuracy, based on their applications. Micro-cutting edge shapes also vary greatly in ridgeline profile and section. The proposed method is shape fabrication after laser hardening, which easily addresses these issues. In the present paper, effects of the proposed method are discussed and the results of a demonstration test are introduced.
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Authors: Hiroyuki Kodama, Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa
Abstract: The uses of data mining methods to support workers decide on reasonable cutting conditions has been investigated in this work. The aim of our research is to find new knowledge by applying data mining techniques to a tool catalog. Hierarchical and non-hierarchical clustering of catalog data as well as multiple regression analysis was used. The K-means method was used and on the shape presented in the catalog data and grouped end mills from the viewpoint of the tool's shape, which here means the ratio of dimensions has been focused. The numbers of variables were decreased using hierarchical cluster analysis. In addition, an expression for calculating the better cutting conditions was found and the calculated values were compared with the catalog values. There were three cutting conditions: conditions recommended in the catalog, conditions derived by data mining, and proven cutting conditions for die machining (rough processing).
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Authors: Hiroyuki Kodama, Masatoshi Shindou, Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa
Abstract: We proposed the data-mining methods using hierarchical and non-hierarchical clustering methods to help engineers decide appropriate end-milling conditions. The aim of our research is to construct a system that uses clustering techniques and tool catalog data to support the decision of end-milling conditions for difficult-to-cut materials. We used variable cluster analysis and the K-means method to find tool shape parameters that had a linear relationship with the end-milling conditions listed in the catalog. We used the response surface method and significant tool shape parameters obtained by clustering to derive end-milling condition. Milling experiments using a square end mill under two sets of end-milling conditions (conditions derived from the end-milling condition decision support system and conditions suggested by expert engineers) for difficult-to-cut materials (austenite stainless steel) showed that catalog mining can be used to derive guidelines for deciding end-milling conditions.
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Authors: Heisaburo Nakagawa, Keiji Ogawa, Satoshi Demachi, Hideyasu Hasegawa
Abstract: In this study we attempted to suppress chatter vibration in end-milling of austenitic stainless steels with an end-mill having different helix angles. We showed there were two types of chatter vibration in end-milling with a conventional end-mill with regular helix angle. The two types of chatter vibration depend on the cutting speed. We detected these two types of chatter vibration by the developed monitoring method using laser Doppler vibrometers. We classified the two types of chatter vibration according to chatter generating tendency, frequency and vibration mode. We showed that chatter vibration generated at lower cutting speeds was regenerative chatter vibration. On the other hand, chatter vibration generated at higher cutting speeds was another type. We showed that a end-mill with different helix angles could prevent generative chatter vibration at lower cutting speeds and was also effective in suppressing chatter vibration at higher cutting speeds.
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Authors: Hiroyuki Kodama, Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa
Abstract: Data-mining methods using hierarchical and non-hierarchical clustering are proposed that will help engineers determine appropriate end-milling conditions. We have constructed a system that uses clustering techniques and tool catalog data to support the determination of end-milling conditions for different types of difficult-to-cut materials such as austenitic stainless steel, Ni-base superalloy, and titanium alloy. Variable cluster analysis and the K-means method were used together to identify tool shape parameters that have a linear relationship with the end-milling conditions listed in the catalogs. The response surface method and significant tool shape parameters obtained by clustering were used to derive end-milling condition decision equations, which were used to determine the indicative end-milling conditions for each material. Comparison with the conditions recommended by toolmakers demonstrated that our proposed system can be used to determine the cutting speeds for various difficult-to-cut materials.
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Authors: Tomohiro Nagawaki, Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa
Abstract: Recently, with regard to global warming energy shortage, the saving energy has become a global issue. The demand for variety, variable production, high speed, high accuracy, and complex processing in the manufacturing fields has been emerged. Furthermore, automatic extinction of computer numerical control (CNC) screens and automatically hold of oil pressure pump in idling has been raise to do on research. On the contrary, there are few reports dealing with reducing power consumption based on existing machining tools system. The method presented in this report can be applied to various size and weight of machining tools. The experimental result of standby power and minimum power with emergency stop circuit of various machining tools is discussed in this research work. To expand the stage of the proposed method, a brand new system is developed. As a result, power consumption of a machining tool with the phase of idling can be effectively reduced through emergency stop circuit. By activating emergency stop circuit, power consumption can be equalized with the condition of main power-ON only. The standby electric power increases along with increasing weight of machining tools. Through the proposed original system, it is possible to set switching of servo ON and OFF to each section. Consequently, the methodology would be applied into many fields of precision processing.
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Authors: Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa, Takahiro Kono, Daisuke Mitsuoka
Abstract: Recently, demand has been increasing for various kinds and volumes of manufacturing systems. Also, the importance of the Automated Guided Vehicle (AGV) is increasing because it can flexibly correspond to the change of equipment in a factory. This paper describes an autonomous conveyance system for AGV based on a taxi transportation strategy. The system focuses on knowledge of a flexible taxi system in traffic engineering. A taxi is a transport unit in a traffic system with higher flexibility in traveling routes and arrival/departure points compared with railways and buses. In the present report, the waiting mode of a taxi is applied as an AGV rule and investigated to verify the effect of the proposed system. Moreover, the effect of multi-loaded AGV on system performance such as matching time and conveyance efficiency is investigated. A numerical experiment has been conducted to evaluate them. As a result, it was found that introduction of multi-loaded AGV is effective at reducing matching time without conveyance efficiency decrease.
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Authors: Shinya Imura, Keiji Ogawa, Toshiki Hirogaki, Eiichi Aoyama
Abstract: Bamboo grows faster than other renewable natural materials. Bamboo fiber, in particular, has attracted attention as an environmentally superior material. Therefore, we propose a sustainable manufacturing system using bamboo. A method is also proposed for extracting bamboo fibers end-milled using a machining center with in-situ measurement. Bamboo fibers with highly precise shapes are efficiently acquired. Previously, we proposed the fabrication of a binder-free composite by a hot press forming method that only uses bamboo fibers extracted by a machining center. We experimentally demonstrated various hot press forming conditions and achieved proper ones to optimize the forming process. However, we have not yet constructed a method to obtain the best fiber extracting and molding conditions considering both its efficiency and performance. Therefore, in this report, we investigate the influence of the length of used bamboo fiber on the characteristics of the molded products, as its length deeply affects the extracting efficiency and focuses on a degradable plastic as a standard of molded product strength.
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Authors: Yota Takagi, Keiji Ogawa, Toshiki Hirogaki, Eiichi Aoyama
Abstract: Bamboo grows faster than other renewable natural materials. Bamboo fibre, in particular, has attracted attention as an environmentally superior material. Therefore, we proposed a sustainable manufacturing system using bamboo. An extraction method of bamboo fibres end-milled using a machining centre with in-situ measurement was also proposed. Bamboo fibres with high precision shapes are efficiently acquired. Previously, we proposed the fabrication of binder-free composite by a hot press forming method that only uses bamboo fibres extracted by a machining centre. We experimentally demonstrated various hot press forming conditions and achieved proper ones to optimize the forming process. However, when the environment changes, the characteristics of the binder-free composite are not known. If we want to use the binder-free composite, we have to know how much it is affected by the external environment for use as a mechanical object. Therefore, we investigated the changes of the characteristics at high temperature and high humidity.
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Authors: Kuniyoshi Obata, Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa
Abstract: Electrical circuits of Printed Wiring Boards (PWBs) have become multi-layered. Therefore, the formation of micro-blind holes for interlayer electrical connections (blind via holes: BVH) is required. As a result, Cu-direct laser drilling is attracting attention. However, Cu-direct drilling is problematic in that it produces a copper overhang as a result of copper and resin, which have different decomposition points, being melted simultaneously. In addition, the state of PWB surface after the laser drilling is very important. However, this procedure restricts the board density that can be achieved as a result of the limited positional accuracy of the etching process. Consequently, using a Cu-direct drilling process, which does not require etching of the copper foil, to drill BVHs to connect copper foils using a CO2 laser beam has been receiving considerable attention for the next-generation high density PWB manufacturing. However, in the Cu process of generating a direct and overhang problem, there is the problem of accuracy on the substrate surface. In contrast, in-depth research on quality companies has not been performed. Thus, we observe the removal process. Furthermore, we demonstrated reduced overhang.
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