• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.561-562
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.627-628
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• 2007

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.571-572
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• 2011

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.1
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• pp.50-55
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• 2012

The important problem in high speed spindle is to reduce and minimize the thermal effect by motor and bearing. This paper presents the thermal characteristic analysis for a high speed spindle with and without cooling at the rear part, considering the viscosity and the flow rate of cooling oil. A high speed spindle is composed of angular contact ceramic ball bearings, high speed built-in motor, oil jacket cooling and so on. The thermal analyses of high speed spindle need to minimize the thermal effect and maximize the cooling effect and they are carried out under the various cooling conditions. Heat generations of the bearing and the high speed motor are estimated from the theoretical and experimental data. This result can be applied to the design and manufacture of a high speed motor spindle.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.3
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• pp.278-283
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• 2013

While Built-in Spindle is working in machining center, the tool is changed by ATC(Automatic Tool Changer) automatically. However, impurities could be stacked in front of spindle because of chips formation while machining, and positional error between spindle and tool could be generated. Compressed air holes are necessary for removal of the impurities. But, the diameter and number of compressed air hole are different for each built-in spindle in market. In this paper, flow analysis is carried out to find out the efficient figuration of the compressed air hole by using velocity and pressure distributions.

• 한국기계연구소 소보
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• s.16
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• pp.83-94
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• 1986

Grinding machine, one of the precision machine tool, requires high accuracy in spindle system. But, recent Inspection and Test reports by KIMM shows high inferio¬rity ratio in home-made grinding machines and points out that this is mainly due to the lack of design ability and assembling technique of spindle system. In this paper, therefore, static stiffness, dynamic characteristics, thermal defor¬mation and error motion of spindle system were studied. With these results, we presented the general data to design and assemble the spindle system. Test of spindle system modified by this study showed that several factors affecting machining accuracy were improved largely.

• Economic and Environmental Geology
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• v.34 no.1
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• pp.133-146
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• 2001

We report the results of structural field observation and measurement of anisotropy of magnetic susceptibility (AMS) of the diamictitic Hwanggangri Formation distributed in Chungju-Suanbo area of the Okchon Belt, Korea. The outcrops of the Hwanggangri Formation show two types of cleavage in general: slaty cleavage (SI) and crenulation cleavage (5z). 5] cleavage is, however, well observable only in the notheastem (NE) part of study area, while overwhelmed by 52 cleavage in the southwestern (5W) part, indicating stronger later deformation in 5W part of the study area. This partitioning of the study area is corroborated by both IRM and AMS parameters: NE part of the study area is characterized by higher IRM intensity, higher bulk magnetic susceptibility, higher AM5 degree, and by oblate shape of magnetic susceptibility ellipsoid. Their values become drastically lowered toward southwest, and reach to a stable minimum in the whole 5W part of the study area. In addition, degree of both metamorphism and deformation tends to increase gradually from northeast toward southwest and also from northwest toward southeast in the study area. Based on the distribution pattern of the principal axes ( $k_1, k_2, k_3$ axes) of magnetic anisotropy ellipsoids revealed in the NE part of the study area, three episodes of deformation ( $D_1, D_2, D_3$ ) are recognized: D_1$ deformation produced $S_2$ cleavage with NE-5W trend, which is caused by a strong NW-SE tlattening of a coaxial pure shear. $D_2$ deformation produced 5z cleavage characterized by a non-coaxial deformation. It was caused by a ductile or semi-ductile thrusting toward NW and concurrent sinistral shearing along $S_2$ cleavage plane. Lastly, $D_3$ deformation produced tlexural folding of all previous structures with a nearly horizontal NE fold axis. Distribution pattern of the principal axes of magnetic anisotropy ellipsoid from the SW part of the study area, on the other hand, does not show any coherency among sites or samples. We interpret that this dispersed pattern of $k_1, k_2, k_3$ axes together with lower anisotropy strength indicates that magnetic fabrics in the SW part have been disturbed either by a superposition of strong deformation/metamorphism or by a kind of reciprocal strain due to an overlapping of $D_1$ and $D_2$ or by both processes.

• Korean Journal of Environment and Ecology
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• v.11 no.2
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• pp.217-223
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• 1997

도시생태계는 주 구성원인 인간의 사회구조와 경제활동이 주축이 되고, 부 구성원인 자연이 주 구성원과 상호관계를 받으면서 존재하는 실체이다. 도시 생태계는 사회구조와 경제활동이 일어나는 핵심부와 그것과 직접 관계하는 기초부 및 물질과 에너지의 공급원, 수용원 및 축적을 담당하는 외부환경의 세 부위로 구성되는, 사회-경제-자연-복합 생태계SENCE)로 이해할 수 있다. 도시생태계는 자연생태계의 원리에 따라 기능을 조절하고 시스템모델 기법으로 분석할 수 있다. 도시생태계의 범위는 그 크기, 독립영양과 종속영양의 평형, 기능적 활성 및 발달단계에 따른 ㅗ이부환경(입력환경과 출력환경)의 변화에 의하여 크게 달라진다. 생태학자나 환경학자는 도시생태계를 자연만을 대상으로 연구하였지만 앞으로는 사회학자와 공동으로 연구하여야 문제의 정곡에 접근할 수 있을 것이다.

• The Optical Journal
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• s.106
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• pp.23-29
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• 2006

금년 7월부터 산업자원부, 한국산업기술재단, 특허정보원과 일반기계 중 4개 업종인 정밀광학기기, 가스기기, 섬유기계, 냉동기기가 1팀으로 구성되어 각 분야별 산업의 미래 발전상을 수립중에 있다. 현재 한국광학기기협회를 주축으로 진행하고 있는 정밀광학기기산업의 기술로드맵이 완성되면 광학산업의 비전제시는 물론 정부 기술개발사업 참여를 위한 기본 자료로 활용이 가능할 것으로 예상되어 관련 산학연 관계자들이 뜨거운 관심을 모으고 있다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.1
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• pp.33-43
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• 1998

High cutting speeds and feeds are essential requirements of a machine tool structure to accomplish its basic function which is to produce a workpiece of the required geometric form with an acceptable surface finish at as high a rate of production as is economically possible. Since the bearings in high speed spindle units are the main heat source of the total cutting system, in this work, the thermal characteristics of the spindle bearing system with a tilting axis were investigated using finite element methods to improve the performance of the spindle bearing system. Based on the theoretical results, a specially designed prototype spindle bearing system has been manufactured. Using the manufactured spindle bearing system, the thermal characteristics were measured. From the comparison of the experimental results with the theoretical ones, it was found that the finite element method predicted well the thermal characteristics of the spindle bearing system.