• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.82-87
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• 2004

Experimental modal analysis is an effective tool to investigate the dynamic behavior of machining centers. This paper presents the measurement system and experimental investigation on the modal analysis of machining centers. The modal analysis shows the weak part of the machining center. An important local model of spindle in our experiment, which influences the dynamics of machining process, is proposed in this paper. The results provide the foundation of structure modification for good dynamic behaviors.

• 한국생산제조학회지
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• 제21권5호
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• pp.691-696
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• 2012

In this study, a rigid multi-body dynamic model has been developed for mechatronic analysis to evaluate dynamic behavior of a machine tool. The development environment was the commercialized analysis tool, ADAMS, for rigid multi-body dynamic analysis. A simplified servo control logic was implemented in the tool using its functions in order to negate any external tool of control definition. The advantage of the internal implementation includes convenience of the analysis process by saving time and efforts. Application of this development to a machine tool helps to evaluate its dynamic behavior against feeding its component, to calculate the motor torque, and to optimize parameters of the control logic.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.477-478
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• 2006

This paper presents the results of miniaturized micro milling machine tool development for micro precision machining process. Finite element analysis has been performed to know the relationship between design dimensional variables and structural stiffness in terms of static, dynamic, thermal aspects. Design optimization has been performed to optimize the design variables of micro machine tool to minimize the volume, weight and deformation of machine tool structure and to maximize the stiffness in terms of static, dynamic, and thermal characteristics. This study presents the assessment of the technology incentive for the minimization of machine tool in the quantitative context of static, dynamic stiffness, thermal resistance and thus the accuracy implications.

• 한국정밀공학회지
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• 제18권2호
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• pp.126-131
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• 2001

One of the major obstacles in testing or evaluating precisely the thermal behavior of a machine tool is the difficulty in measuring the heat transfer coefficients on the surfaces by a conventional method. This paper presents a new approach based on the inverse method to identify the values of heat transfer coefficients by using temperature changes measured on the surfaces of a machine tool during a short period in its operating. In the present method, a machine tool structure is modeled by the finite element method and the characteristic curves of the temperature change at several points on machine tool surfaces are theoretically derived in the form that they contain the heat transfer coefficient as an unfixed heat source are approximated so that the theoretical characteristic curves of temperature change fit the measured ones as closely as possible.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 1998년도 추계학술대회 및 정기총회
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• pp.204-208
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• 1998

The fundamental issues to evaluate machine tool's performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. The designed virtual machining system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.53-58
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• 1998

Case hardening of tool steel(SK5) was investigated after YAG laser irradiation. In the case of beam passes, martensite formed in the melt zone and in former pearlite regions of the austenization zone exhibited very high Vickers Hardness values. The molten depth and radius, micro structure, hardness were investigated as a function of defocusing distance, pulse width, and power density.

• 한국기계가공학회지
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• 제19권8호
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• pp.43-49
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• 2020

The growth of the AR/VR market due to the advent of the 4th Industrial Revolution begins with the development of the display industry. The development of OLED and flexible displays is further accelerated by the development of R2R technology. Micro-processing technology using a fast tool servo (FTS), the core technology in R2R processes, is making technological progress in increasingly diverse ways. This paper proposes a method to develop an FTS for horizontal driving and presents this method through experiments and analyses. To develop a swing-type FTS based on a seesaw motion, a rotational moment hinge structure was designed for each type, and research was conducted to determine an effective design method. A cantilever-based swing-type FTS was developed in two variations: one with single-side hinges and another with dual-side hinges. The parameters in the design of the swing-type FTS are rotational moment, natural frequency, and material selection. In conclusion, an FTS with a single-side hinge demonstrates the high performance required for micro processing.

• 전자공학회논문지A
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• 제32A권12호
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• pp.149-158
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• 1995

This paper describes the development of a software tool LCD FRAME that may guide the analyzing process for the electrical characteristics and the design procedure for constructing the thin film transistor liquid crystal display(TFT/LCD) packages. LCD FRAME can analyze its electrical characteristics from the TFT/LCD system package configuration, and provide the design variables to meet the user's requirements. These analysis and design procedure can be done in real time according to the model at simplified package level of TFT/LCD. LCD_FRAME is an object-oriented expert system which considers package elements as objects. With this LCD_FRAME software tool, we analyzed the I-V characteristics of a-Si TFT and its signal distortion which has maximum 1.58 $\mu$s delay along the panel scan line of the package containing 480 ${\times}$ 240 pixels. We designed the package structure of maximum 6.35 $\mu$s signal delays and 3360 ${\times}$ 780 pixels, and as a result we showed that the proper structure of 20 $\mu$m scan line width, 60$\mu$m panel TFT gate width and 8 $\mu$m gate length. This LCD_FRAME software tool provides results of the analysis and the design in the form of input files of the SPICE program, text data files, and graphic charts.

• 한국실내디자인학회논문집
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• 제25권3호
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• pp.31-39
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• 2016

This study is aimed to increase the possibility of using the Christopher Alexander's pattern language. The methodology of this study is (i) to analyze the pattern language by using the network analysis tool in order to understand the complicate network structure of the pattern language, and (ii) to apply the Alexander's method of using the pattern language by using the network analysis tool (Gephi) and to examine the feasibility of the network analysis tool as a tool for using the pattern language. Firstly, as a result of analysing the pattern language, (i) the pattern language classified by pattern number is distinguished by the patterns of towns, buildings and construction, among which the pattern of buildings plays a key function in the networks; (ii) the buildings functions a medium connecting between the towns and the construction; and (iii) the pattern language is divided into 6 sub-modules, through which the user can select a pattern. Secondly, the result of using the network analysis tool as a tool for using the pattern language (i) suggests the new method of using the pattern language by using the network analysis tool (Gephi); (ii) makes it possible to easily figure out the characteristics of the links between the patterns; and (iii) increases the completeness of the pattern language by making it easy to find out the sub-patterns in selecting a pattern.

• 한국정밀공학회지
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• 제21권8호
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• pp.34-42
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• 2004

A new polishing technique for three dimensional micro/meso-scale parts is suggested using a micro quill and a magnetic chain structure. The principle of this method is to polish the target surface with the collected magnetic brushes at a micro tool by the non-uniform magnetic field generated around the tool. In a typical magnetic abrasive finishing process magnetic particles and abrasive particles are unbonded each other. But, to finish the three dimensional small parts bonded magnetic abrasive have to be used. Bonded magnetic abrasives are made from direct bonding, and their polishing characteristics are also examined. Alumina, silicon carbide and diamond micro powders are used as abrasives. Base metal matrix is carbonyl iron powder. It is found that bonded magnetic abrasives are superior to unbonded one by experiment. finally, the polished surface roughness is evaluated by atomic force microscope.