• Transactions of Materials Processing
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• v.13 no.3
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• pp.253-261
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• 2004

The machining technology for the brittle materials such as ceramics are applied to the fields of MEMS(micro electromechanical system) by the progress of new machining technologies such as Etching, Diamond machining, Micro drilling, EDM(Electro discharge machining), ECDM(Electro discharge machining), USM(Ultrasonic machining), LBM(Laser beam machining), EBM(Electron beam machining). Especially, the USM technology can be applied to the dieletric brittle materials such as silicon, borosilicate glass, silicon nitride, quartz and ceramics with high aspect ratio. The micro machining system with machining force controlled position servo is developed in this paper and the optimized ultrasonic machining algorithm is constructed by the force controlled position servo control. The load cell is adapted in the force measuring and the servo control algorithm, suit for the ultrasonic machining characteristics, is estabilished with using the PID auto-tunning functions at the PMAC system which is generally adapted in the field of robot industries. The precision force signal amplifier is constructed with high precision operational amplifier AD524. The vacuum adsorption chuck which is made of titanum and internal flow line is engraved, is used in the workpiece fixing. The mahining results by USM shows that there are some deviation between the force command and the actual machining force that the servo control algorithm should be applied in the machining procedures. Therefore, the constant force controlled position servo system is developed for the micro USM system and by the examination machining process in USM, the stable USM system is realized by tracking the average value of machining force.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.263-268
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• 2001

The needs for precision machining of micro to milli parts have been increased as the industry require high quality products, especially for the micro-machining of IT products. The ultra-precision machining system is essential for the micro machining of fine structures, which insures machining accuracy, low systematic and random error and repeatability. In this study, we developed micro machining system, which is equipped with air bearing stage for ultra precision machining and also we present the results of V-grooving experiments, conducted by the developed system, to verify the performance of system. The results show that the machined V-grooving had good accuracy with repeatable stability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.142-147
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• 2012

Machining tool conditions directly affect to quality of product and productivity of manufacturing. Many researches performed for tool condition monitoring in machining process to improve quality and productivity. Conventional methods use characteristics of signal for cutting force, motor current consumption, vibration of machine tools and machining sound. Recently, diameter of machining tool is become smaller for minimizing of mechanical parts. Tool condition monitoring using conventional methods are relatively difficult because micro machining using small diameter tool has low machining load and high cutting speed. These days, the direct monitoring for tool conditions using vision system is performed actively. But, vision system is affected by external conditions such as back ground of image and illumination. In this study, minimizing technology of external conditions using distribution analysis of image data are developed in micro machining using small diameter drill and tap. The image data is gathered from vision system. Several sets of experiment results are performed to verify the characteristics of the proposed machining technology.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.7
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• pp.761-768
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• 2011

The large surface micro machining system includes the equipments and processes for manufacturing the ultra precision micro patterned products with large surface through the mechanical machining. Recent major issue on the micro machining technology may be the development of optical parts for the back light unit of display which has the largest market. This special issue makes up with three parts; the large surface micro machining system and machine, machining process and forming process. In this paper, the state-of-the-art and core technology of large surface micro machining system is introduced with focus on the manufacturing technology for the back light unit of LCD TV. Then, some research results on the development of a roll die lathe is introduced which involves the concept of machine design, improvement of thermal characteristics in the spindle system, improvement of relative parallelism and straightness between spindle system and long stroke feed table, machining of micro pitch patterns. Finally, the direct forming process is introduced as the future work in the large surface micro machining field.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.6 s.171
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• pp.109-117
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• 2005

In case of fine machining processes, the cutting state monitoring by a skilled operator is impossible because the physical changes generated during fine machining are very weak. To realize the high efficient and precise fine machining, it is necessary to develop the sensor based monitoring system which is able to detect the fine changes of cutting state. In this paper, the fine acoustic emission monitoring system is developed to monitor the state of the fine machining process. The developed system consists of the AE sensor and the AE signal processing unit. And this has the high-sensitivity and bandwidth which can detect fine AE signal generated during fine machining process. In order to investigate the feasibility of the developed system, evaluation experiments were performed in the fine fixed-abrasive machining processes such as polishing and glass ferrule slicing. Experimental results show that the developed monitoring system possesses an excellent real-time monitoring capability at fine machining processes.

• IE interfaces
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• v.15 no.2
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• pp.147-151
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• 2002

Presented in this paper is a prototype of dedicated CAM system for a human bust, not a relief, machining. The input of this system is a STL file which comes from measuring machine, and the output is machining data for a 3-axis CNC milling machine with an index table. The system consists of three main modules, which are shape import and transformation, modeling of jig and fixture, and calculation of machining area. Proposed system architecture and the main modules are briefly described. To get machining region for semi-finish and finish machining stages, two concepts of machining area, machinable and scannable, were tried. Machinable area was suitable for the purpose.

• Journal of Korean Institute of Industrial Engineers
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• v.21 no.1
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• pp.51-65
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• 1995

This paper presents an automatic fixture planning system for machining processes of prismatic parts. A rationalized approach to integrate fixture planning with process planning is proposed and representation schemes for workpiece, part design information with features, machine tools, cutting tools and fixtures are developed. The proposed system implements two activities of fixture planning such as machining of reference surfaces and machining of features. For machining of reference surfaces, the machining sequence of reference surfaces is determined by using decision tables, which are drawn from relations of part dimension, degree of surface roughness, fixture type and its capacity, cutting tool's capacity and experienced planners' knowledge. For machining of features, a preferential machining orientation is selected for its feature which can be machined in more than one direction, and features with the same machining orientation are grouped, and the machining sequence of features is determined by interactive mode. A case study is performed to show the performance of the proposed system.

• Korean Journal of Computational Design and Engineering
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• v.8 no.1
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• pp.35-40
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• 2003

In this paper, we present the methods to develop a Web-based CAM system that is capable to simulate machining processes in solid model form through internet. The methods include the dynamic representation on Web of machining operation, workpiece definition on the request of users, interpretation technique of NC par programs through CORBA, and algorithm for efficient machining simulation. Based on the methods, a Web-based CAM system it implemented at http://virtual.ulsan.ac.kr. Using the Web-based CAM system, public users tan simulate machining processes by own NC part programs.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.79-88
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• 1998

This study deals with the development of CAM system which can machine and measure any shape of mold and die by machining center and coordinate measureing machine . The overall goal of the CAM system is to achieve the mold and die machining , from digitizing through to final cutting. The hardware of the system comprises PC and machining center. CMM. There are three steps in the mold and die machining. (1) measuring of physical model by the CMM, (2) geometric modeling by the CAD system, (3) generation of NC code by the tool path compensated for tool radius. It is developed a software package, with which can conduct a micro CAM system in the PC without economical burden.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.589-592
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• 2003

In the machining process of micros shape by using high-precision machining system and micro end-mill, it is important for machining characters of tools to be grasped in order to stably use tools of micro end-mill. In this study. we carried out an analytical experiment of basic machining features by using end-mill tools for the purpose of damage prevention and manufacture of high quality when the tools of micro end-mill are used. This experiment used a micro machining system with high precision and a variety of end-mill tools commercialized from tens to hundreds microns in diameter. To establish an optimal machining condition without tool damage, cutting force was analyzed according to the changes of tool diameter and cutting conditions such as cutting speed. feed rate, depth of cut. And an examination was performed for the shape and surface illumination of machining surface according to the changes of machining conditions. Based on these micro machining conditions, micro square pillar, cylinder shaft. thin wall with high aspect ratio, and micro 3-D structures such as micro gear and fan were manufactured.