• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.50-57
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• 2006

The investigation of microscopic precision in high speed endmilling is necessary for machinability evaluation, and the environmentally conscious machining technology have more important position in recent machining process. The microscopic precision of workpiece is influenced by machining environments variation as cutting fluid type and lubricant method. In this study, the cutting forces according to variation of cooling and lubrication are investigated by specially designed tool dynamometer. And the surface roughness, micro hardness and residual stress are evaluated according to machining environment. The characteristics of damaged layer in environmentally conscious machining and conventional machining using cutting fluid are compared experimentally.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.352-357
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• 2004

The high speed machining center(HMC) has been widely applied to manufacture a die and machine elements product in industrial field. Because the evaluation for HMC is not sufficiently performed, ineffective machining is occasionally conducted in machining industry. In this study, the dynamic characteristics of newly developed machining center is evaluated under running condition and the machinability is investigated experimentally. Also, the in-process measuring instrument which can measure the tool wear on the machine were developed by using the CCD and exclusive jig and calibration instrument for tool wear measurement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.2
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• pp.228-234
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• 2001

To obtain precise machined surface and high productivity in machining, high speed end milling has beed studied recently. Though high speed end milling is explicitly effective for precision surface generation geometrically, tool deflection, chatter vibration and frequency characteristics of end milling system deteriorate the theoretical surface. In this study, simulation algorithm and programming method are suggested to simulate machined surface using acceleration signal in high speed end milling. This simulation is conducted by considering vibrational effect of spindle system which was not considered by other investigators. Good agreements were obtained between simulated results and experimental results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.39-44
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• 2005

With the development of high speed and accuracy machining, the micro-chips are formed in the machining process and broken particles are circulated with the cutting fluid. The surface roughness and accuracy of part are deteriorated because the metal particles included in the cutting fluid are embedded on machined surface. In this study, the influences of particles for the machined surface according to filtering degrees are evaluated and the embedding mechanism is suggested.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.182-183
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• 2009

플라즈마 원자층 증착법을 이용하여 Ru-TiN 빅막을 합성하였다. 박막 내 Ru의 함량은 Ru의 unit-cycle의 수에 따라 선형적으로 증가하였으며, Ru 함량이 증가함에 따라 박막의 비저항을 $3700{\mu}{\Omega}{\cdot}cm$에서 $190{\mu}{\Omega}{\cdot}cm$까지 자유롭게 조절할 수 있었다. Ru의 함량이 0.40 이상인 경우, Ru과 TiN 두물질이 교차 증착되어 서로의 결정 성장을 충분히 억제함으로서, 비정질구조를 가짐을 확인할 수 있었다. 또한, $O_2$ 분위기에서 열처리를 진행한 결과, Ru의 조성비가 0.40이상인 경우 $700^{\circ}C$까지 면저항의 변화가 거의 없음을 확인할 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.211-211
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• 2009

높은 이온화율과 복잡한 형상의 모재에도 표면 도포성 및 균일성을 나타내는 아크이온플래이팅 기술과 비전도성 세라믹 타겟물질에 적용가능한 스퍼터링 기술이 결합된 하이브리드 코팅 시스템(Hybrid coating system)을 이용하였다. 그리고 Cr-Al-N과 Cr-Si-N 코팅막의 강화 기구를 복합시킨 새로운 개념의 Cr-Al-Si-N 코팅막을 초경(WC-Co)시험편에 증착하여 Si 첨가량에 따른 미세구조의 미세경도 특성을 파악하였다. 공구성능 평가는 고속가공조건하에 마이크로 밀링기에서 무코팅(초경공구), Cr-Al-Si-N (Si : 0, 4.5, 8.7, 16 at.%) 코팅 마이크로엔드밀에 대하여 공구마멸에 대한 공구수명을 비교, 평가하였다.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.8
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• pp.81-87
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• 1998

High-speed machining is one of the most effective technologies to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and molds. In this paper, high-speed machining for HP-4 die material was carried out with a coated tungsten carbide ball endmill. In the high-speed machining, the cutting force and surface roughness of workpiece show various characteristics in different cutting conditions. Especially, the surface roughness of the workpiece depends largely on pick feed and feed-per-revolution of the ball endmill. In the condition where pick feed and feed-per-revolution are equal, better surface roughness is measured. By obtaining good surface roughness at high speed, efficiency of machining can be increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.36-40
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• 1996

The high-speed machining is one of the most effective technology to improve productivity. Because of the high speed and high feedrate, high-speed machining can give great advantages for the machining of dies and moulds. In this paper, high-speed milling for HP-4 die material was carried out with coated tungsten carbide ball endmill. In the high-speed machining, the cutting force and surface roughness of workpiece show very various characteristics at different cutting conditions. Especially surface roughness of workpiece depends largely on pick feed and feed per revolution of ball endmill. In the condition that pick feed and feed per revolution are equal, better surface roughness is measured. By obtaining good surface roughness at high speed, efficiency of machining can be increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.328-332
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• 1996

The compressor is one of important elements in refrigerator cycle and play an important role of refrigeration efficiency and quality. Therefore it is very important to monitor state of normal and abnormal compressor. In this research, technic of AE is used for monitoring abnormal rotary compressor and an AE parameter which is a most proper parameter to monitor the abnormal state of compressor is determined by signal processing, Finally, the monitoring result of rotary compressor is agreement with the result of life test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.61-66
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• 1994

Tool condition monitoring is one of the most important aspects to improve productivity and quality and to achieve intelligent machining system. The tool state is classified into three groups as chipping, wear and fracture. In this study, wear of a ceramic cutting tool for hardened die material (SKD11) was investigated. Flank wear was occured more dominant than crarer wear. Therefore, to predict flank wear, the modeling of cutting force has been performed. The modeling of cutting force by an assumption that act the stress distribution on the tool face obtained through a numerical analysis. The relationships between the cutting force and the tool wear can be constructed by machining paraneters with cutting conditions. Experiments were performed under the various cutting conditions to ensure the validity of force models. The theoretical predictions of the flank wear is approximately in good agreement with experimental result.