• 한국정밀공학회지
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• 제19권7호
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• pp.64-70
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• 2002

The positioning system fur the ultraprecision machine tool should have nanometer order of positioning resolution. For the purpose of achieving that resolution, various feed drive devices have been proposed and currently hydrostatic lead screw and friction drive are paid attention. It is reported that an angstrom resolution can be achieved by using twist-roller friction drive. So we have manufactured ultraprecision feeding system driven by the twist-roller friction drive and perform performance assessment for problem definition and solution finding. As a result, we found that the twist-roller friction drive is mechanically suitable for ultraprecision positioning but some considerations are needed to get higher resolution.

• 한국정밀공학회지
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• 제30권12호
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• pp.1313-1320
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• 2013

An ultraprecision multi-axis machine tool has been designed and developed in our laboratory. The machine tool has four moving axes which are composed of three linear axes and one rotational axis. It has a gantry type structure and the Z-axis is on the X-axis and the C-axis, on which a workpiece is located, is inside the Y-axis. This paper shows control performance improving method and procedure for the ultra-precision positioning control of a hydrostatic bearing guided linear axis. Through improvements of electrical and mechanical components for the control system such as control electronics and oil pumping systems, the control disturbing noise is decreased. Also by the frequency domain analysis of control system those problem-making system components are identified and modified with analytical methods. The controller is analyzed and designed from frequency domain data and system information. In the experimental control results the nanometer order control result is successfully presented.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.8-12
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• 2005

The positioning system for an ultra precision machine tool must be accurate to the order of a nanometer. Various feed drive devices have been proposed to achieve this resolution; currently, most attention is directed towards hydrostatic lead screws and friction drives. It has been reported that a positioning resolution accurate to an angstrom can be achieved using a twist-roller friction drive. Therefore, we manufactured an ultra precision positioning system driven by a twist-roller friction drive and assessed its performance when defining problems and finding solutions. Our study showed that the twist-roller friction drive is mechanically suitable for ultra precision positioning, but some considerations are required to obtain a higher resolution.

• 한국정밀공학회지
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• 제12권1호
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• pp.104-111
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• 1995

The needs of ultraprecision machine tools, which manufacture and machine the high precision parts used in computers, semiconductors and othe rprecise machines, have been increased recentrly. So it is important to design the driving parts of the ultraprecision machine tools which affect significantly on the performance of them. In this paper, the dynamic analyses on the belt-drive system were studied. The correlational equations between the acoustic natural frequency and the tension of belt were derived by experiments. The dynamic delections while the dynamic loads on the motor system changed were analyzed by the finite element analysis. The nonlinear characteristics of the bearings on the dynamic performance was studied and the belt connecting the motor to the spindle of a machine tool was modeled by the truss element and the beam element.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.446-449
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• 1995

In this paper, the accurate end position control method of ultraprecision machine tool post using piezoelectric material as an micro positonong devics is presented. This method employs the classical PID feedback and uses an additional notch filter which eliminates the resonance characteristics of controlled plant. And the simple predictor is added to make use of the future value of desired input for better tracking performance. To show the feasibilty of proposed method, the PC-based experimental apparacy can be obtained. Using method, Al specimen of diameter 100mm was cut under practical machining condition to test the practicability of proposed method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.123-128
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• 2005

A novel tri-mode ultraprecision positioning system for machine tools and measuring machine is proposed. The basic coarse mode uses a Twist-roller Friction Drive (abbr. TFD), and controls several tens of millimeters of the machine-table travel with nanometer order of positioning resolution. The fine mode also utilizes the TFD with a fine adjusting mechanism. The resolution of the fine mode is in the range of sub-nanometer. For realizing picometer positioning, the ultra-fine mode is executed by using an active aerostatic guideway. On the bearing surface of this active guideway, several Active Inherent Restrictors (abbr. AIRs) are embedded for controlling the table position. An AIR unit consists of a piezoelectric actuator having a through hole, one end of the hole on the bearing surface acts as an inherent restrictor. Owing to the aerostatic mechanism of the AIR, the deformation of the piezoelectric actuator in the AIR unit causes much reduced table displacement. Such motion reduction is effective for ultraprecision positioning. Current positioning resolution of the ultra-fine mode is 50pm, however the final goal of the positioning resolution is expected to be in the order of picometer.

• 한국정밀공학회지
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• 제30권10호
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• pp.1087-1093
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• 2013

In this study, a measurement method of double ball-bar is proposed to measure the geometric errors of an ultra-precision roll mold machine tool. A volumetric error model of the machine tool is established to investigate the effects of the geometric errors to a radius error and a cylindricity of the roll mold. A measurement path is suggested for the geometric errors, and a ball-bar equation is derived to represent the relation between the geometric errors and a measured data of the double ball-bar. Set-up errors, which are inevitable at the double ball-bar installation, also are analyzed and are removed mathematically for the measurement accuracy. In addition, standard uncertainty of the measured geometric errors is analyzed to determine the experimental condition. Finally, the proposed method is tested and verified through simulation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.26-31
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• 2001

Recently, miniaturization and mass production are the main trends in manufacturing fields. Therefore, ultraprecision machining and MEMS technology have been taken more and more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro parts to micro products, such as PDP and IT components, in precision products manufacturing. However, the deburring is significant problem in making smooth and precise parts in micro endmilling. This paper shows removal characteristics of burr generated by micro endmilling process. Additionally, it is necessary to understand the formation mechanism of burr of micro barrier ribs to find proper deburring method.

• 한국공작기계학회논문집
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• 제11권3호
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• pp.14-20
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• 2002

Recently, miniaturization and mass production are the main trends in manufacturing fields. Therefore, ultraprecision machining and MEMS technology have been taken more 7md more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from duo parts to micro products, such as PDP md IT components, in precision products manufacturing. However, decreasing of burr is significant problem in making smooth and precise parts in micro endmilling. This paper shows removal characteristics of burr generated by micro endmilling process. This results satisfies micro endmilling for micro barrier ribs of heights is $50{\mu}m$, $100{\mu}m$, $200{\mu}m$, $300{\mu}m$, and observation from of burr. Additionally, it is necessary to understand the formation mechanism of burr of micro barrier ribs to iud proper decreasing method.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.59-66
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• 2003

This study suggests the new ultraprecision finishing techniques for micro die and mold parts using magnetic field-assisted polishing. Conventional magnetic abrasives have several disadvantages, which are missing of abrasive particle and inequal mixture between magnetic particle and abrasive particle. Therefore, bonded magnetic abrasive particles are fabricated by several method. For example, plasma melting and direct bonding. Carbonyl iron powder is used as magnetic particle there silicon carbide and alumina are abrasive particles. Developed magnetic abrasives are analyzed using SEM. Feasibility of magnetic abrasive and polishing performance of this magnetic abrasive particles also have been investigated. After polishing, surface roughness of workpiece is reduced from 85.4 ㎚ Ra to 9 ㎚ RA.