• 한국정밀공학회지
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• 제29권5호
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• pp.489-493
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• 2012

Automatic tool changers(ATCs) store tools used in a machining center to its magazine and changes the tools automatically. Tools of machine centers are changed and then precisely equipped to spindle system by the ATC. Therefore, the stability and reliability of the ATC is very important. But, there is lack of development and evaluation on basic performance and vibration of the ATCs. So, in this study, a BT40 ATC test bench was developed to verify stability and reliability of BT40 ATCs.

• Environmental Analysis Health and Toxicology
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• 제19권4호
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• pp.353-357
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• 2004

난황단백질인 비탈로제닌을 성숙한 암컷 붕어 혈청으로부터 음이온 교환 크로마토그래피를 이용하여 정제 하였다. 정제한 비탈로제닌을 BALB/c mice를 이용하여 폴리크로날 항체를 생산하였고 이를 protein A column을 사용하여 정제하였다. 또한 이렇게 정제된 폴리크로날 항체를 이용한 붕어 비탈로제닌 측정용 효소면역측정법을 개발하였으며 그 측정 범위는 2∼l,000ng/mL이고 recovery 변동 범위는 88∼112%였다. 또한 이 효소면역측정법을 평가하기 위해 성숙한 수컷 붕어를 1,000ng/L ethinylestradiol(EE$_2$) 에 4주 동안 노출시켜 유도되어지는 비텔로제닌을 측정하였다. 그 결과 성숙한 수컷 붕어의 경우 비탈로제닌이 3주 만에 암컷 붕어의 평균수치만큼 유도됨을 알 수 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 압출 및 인발 심포지엄
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• pp.83-88
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• 1999

This study presents development of an software for process and die design of hot extrusion through square dies. The design of extrusion dies is still an art rather than a science with increasing complexity of shape and thinness of section. Therefore, most of the die design is still dependent on personal judgement, intuition and experience. The objective of this study is to develop an software system which includes a design rule extracted from literatures and experts in the extrusion industry. The system also includes finite element simulation program. The developed system is effectively used to design extrusion processes and dies with lead time and trial extrusion.

• 소성∙가공
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• 제7권4호
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• pp.375-381
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• 1998

This paper presents development of finite element simulation program and analysis of hot extrusion through square dies with a mandrel. The design of extrusion dies is still an art rather than science. Die design for a new extrusion process is developed from through in-plant trials. In the present paper, a three-dimensional steady-state finite element simulation program is developed. Steady-state assumption is used for both the analyses of deformation and temperature. The developed program is effectively used to simulate hollow extrusion of several sections. Distributions of temperature effective strain rate, mean strain rate and mean stress are studied for an effective design of extrusion dies.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.393-396
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• 1997

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feed rate, high-speed machining can give great advantages for the machining of dies and molds. This paper describes on the improvement of machining accuracy in high-speed machining. Depth of cut and feed rate are control factors. The effect of the control factors on machining accuracy is investigated using two-way factorial design.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.785-790
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• 2001

Linear motors can drive a linear motion without intermediate gears, screws or crank shafts. Linear motors can successfully replace ball lead screw in machine tools, because they have a high velocity, acceleration and good positioning accuracy. On the other hand, linear motors emit large amounts of heat and have low efficiency. In this paper, heat sources of a synchronous linear motor with high velocity and force are measured and analyzed. To improve the thermal stiffness of the linear motor, an insulation layer with low thermal conductivity is inserted between cooler and machine table. Some effects of the insulation layer are presented.

• 한국기계가공학회지
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• 제10권5호
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• pp.26-30
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• 2011

Currently, many researches are carried out about tilting index table, which is one of the main component of 5-axis machine tool. The performance of the tilting index table is associated the rotational accuracy which is very important factor for high precision machining because it have an effect on machining error. In this paper, a tilting index table is developed, and the rotational accuracy of the tilting index table using a laser measurement equipment is measured. In addition, a correction value is obtained from the measured value through compensation, and the correction value is used to improve the accuracy of the table. Comparative analysis is carried out for the accuracy of the table before and after compensation. This paper can be used by a reference for performance and reliability advancement of tilting index table.

• 한국기계가공학회지
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• 제8권1호
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• pp.3-9
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• 2009

Recently, a high speed cutting is essential requirement to satisfy latest demand of high precision product and machining of hard materials. However heat generation by high speed rotation causes many problems. The machining error and shortening spindle lifetime by thermal stress is typical example. Generation of heat is mostly caused by sliding at the rotor and bearing. For minimization of heat generation at bearing, decision of the condition of proper lubrication is necessary. The thermal study about 40,000rpm spindle by changing the condition of oil-air lubrication method is carried out in this paper. The results of this paper can be used effectively in the decision of oil-air lubrication condition of other types of spindle for machine tools.

• 한국공작기계학회논문집
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• 제12권4호
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• pp.17-22
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• 2003

This paper presents a new circular curve fitting approach of articulated manipulators, based on least square. The approach aims at gaining the interpolation of circle from n data points, under the condition that the fitted circle should pass both a starting point and an ending point. First a spherical fitting should be performed, using least squares. Then the circular curve fitting can be resulted from the intersection of the fitted sphere and the plane obtained from 3 points, i. e., a starting point, an ending point and the center of a sphere. The proposed algorithms are shown to be efficient by using MATLAB-based simulation.

• 한국공작기계학회논문집
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• 제12권4호
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• pp.77-84
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• 2003

The properties of a machine tool greatly affect machining quality since a machine tool has large variance in its features. Machine tool makers want to find best machining condition with the one that they have built. Machine builders need to develop test specimen since it helps finding characteristics of machine tools when the machining properties of the specimen are analyzed. This paper develops test specimen to identify features of the main spindle, the feeding device, and the frame of a machine tool. The specimen is machined with a high speed machine and the features of the machine are analyzed with test items. They are surface roughness, overshoot in axial movement, errors in circular movement, feeding with small movement and compensational error. This work can improve usability for a machine tool in machining practice.