• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.391-399
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• 2017

This paper presents the effects of the cutting speed and feed rate on the axial shape of flat end-milled down cut side walls. Experiments were performed using the cutting speed, tool diameter, and feed per tooth as variables, and the thrust force and axial shape were measured as the experimental results. The results of this study confirmed that a smaller feed per tooth, which is proportional to the value obtained by dividing the feed rate by the cutting speed, results in a higher axial shape accuracy. In addition, the axial shape can be simplified to a form in which two straight lines having different slopes meet at a singular point. Therefore, it was concluded that the shape accuracy could easily be estimated during the operation and improved by adjusting the feed per tooth.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.5
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• pp.517-528
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• 2012

Inserting a nozzle assembly into a removed cutting space during a continuous cutting operation is necessary in rock excavation using an abrasive waterjet. In this study, a combined two nozzle assembly is used to secure enough removal width. The shape of the cut space is affected by the geometric parameters (standoff distance, nozzle angle, and vertical distance between the nozzle tips) of the combined nozzle assembly. Abrasive waterjet cutting tests are performed with various geometric parameters for granite rock specimens. Optimized geometric parameters for the nozzle inserting process are determined and verified through the experimental tests.

• Journal of the KSME
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• v.28 no.3
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• pp.226-234
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• 1988

공작기계의 자동화에 적용되는 ACO, ACC 및 GAC 등에 대한 원리와 이용방안 그리고 연구개발 되어져야 할 점들에 대하여 수학적인 논술을 피하고 그 기본개념 등을 소개하였다. 궁극적인 자동화의 목표가 공작기계에 인공지능을 부여하여 경험이 없는 작업자라고 하더라도 생산공정을 관리 감독할 수 있도록 하기 위하여는 지능있는 공작기계의 개발이 이루어져야 하겠다. 지능 있는 공작기계의 개발시 고려되어져야 할 사항들을 고찰해 볼 때 공작기계의 ACO, ACC 및 GAC 등에 대한 연구개발에 앞서 절삭공정매카니즘 그 자체의 연구개발은 물론 절삭상황을 실 시간으로 측정 및 인식 할 수 있는 측정장치들에 대한 연구들이 선행되어져야 할 것이고, 선진국 대열에 들어서기 위해서는 공작기계 산업에 대한 육성은 물론 연구개발에 집중적인 투자가 이 루어져야 하겠다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.206-214
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• 1988

To improve the surface waviness in the peripheral milling, the feedrate is controlled so that the cutting force measured in the normal direction to the workpiece is constant. A discrete time first order model between the feedrate and the tool deflection is derived for the control. It has been shown by the analysis that the tool deflection is directly related to the feedrate and largely affects the surface waviness during cutting. The experimental results shown that the surface waviness is drastically improved by the proposed methods.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.39-39
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• 2000

열간단조후 절삭가공하여 냉간 성형가공하는 알루미늄 제품은 열간단조하면 재료가 연화되어 있어 절삭가공시 연속적인 칩이 발생하여 공구와 피삭재를 감고 회전함으로서 가공면 손상, 공구파손 및 작업자의 안전을 초래함에 따라 가공이 어려워 단지 절삭성 개선 목적만을 위해 중간공정으로 T4 열처리하여 절삭가공하고 다시 어닐링처리하여 냉간성형을 하고 최종열처리를 한다. 따라서 본 연구는 열간단조후 제품을 급냉시키면 용제화처리의 효과를 얻어 재료가 경화됨으로써 절삭성이 개선될 수 있다는 이론에 근거하여 T4 열처리를 대체할 수 있는 후처리 방법에 대해 연구하였다. 최적의 후처리방법을 구하기 위해 열간단조후 수냉과 공냉처리를 비교 분석하였고, 열간단조후 냉각처리까지 지연된 시간과 수냉과정에서의 유지시간에 따른 분석을 통해 최적의 작업조건을 선정하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.263-263
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• 2004

엔드밀 가공 공정은 항공산업과 자동차 부품 및 금형 가공 산업에서 널리 사용되고 있다. 정형가공 (near net shape) 기술의 발달에 따라 금형 가공시 허용공차 이내로 표면 오차를 유지하면서 가공시간을 감소시킬 필요성이 증대되었고 이에 따라, 절삭과정을 정확히 나타냄으로써 최종표면 형상을 정확히 예측할 수 있는 절삭모델을 통해 표면형성 예측 시뮬레이터의 개발 필요성이 있어왔다. 본 논문에서는 주어진 절삭조건에서 공구의 처짐과 런아웃을 고려한 절삭력 모델에 대하여 절삭력과 표면형성 데이터를 코딩된 포트란 프로그램에서 얻고 이것을 MFC와 연동시켜 예측 결과를 쉽게 확인할 수 있는 초보단계의 시뮬레이터 개발에 대하여 연구하였다.(중략)

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.1
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• pp.95-103
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• 2015

This paper presents the effects of the tool shape on the geometrical characteristics of flat end-milled side walls. A tool shape is characterized by such parameters as helix angle, number of cutting edges, and diameter. The geometrical characteristics of the side walls are represented by the surface profiles in the feed and axial directions, which are orthogonal to each other. The geometrical defects in each direction are estimated based on the instantaneous apparent cutting areas, which are represented by the interference area between the tool and workpiece and that between the cutting edge and workpiece. It is confirmed that a geometrical defect in the feed direction is formed when the tool leaves the workpiece and the curvature of the tool path changes. Defects in the axial direction are also found in the side walls, except for the defect zone in the feed direction. An up-cut using an end-mill with a steeper helix angle, a greater number of cutting edges, and a smaller diameter are thus found to improve the geometrical accuracy of end-milled side walls.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.5
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• pp.353-359
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• 2017

The classical computer numerical control (CNC) machine is widely used for mold making in various industries. However, while improving the process, it has a negative effect on production quality and worker safety. As a result, the complaints of workers have increased and production quality has decreased. Therefore, we found optimizing cutting conditions to mold industrials for cutting conditions commonly used. However, the problem is the insert tool geometric modeling. In this study, the modeling of an insert tool was performed using the Solidworks program. The insert tool model was imported into the analysis application AdvantEdge, which predicted cutting forces, tool stress, and temperature.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.209-219
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• 2000

A method is developed to evaluate machining process and to determine the optimal machining conditions considering the environmental effects. The method Is based on the evaluation attributes from the general LCA programs and the analysis technique of AHP from HHS. To assist the analysis. the mass models of cutting energy, tools, and fluids are developed. The models may be used for both quantitative prediction of the uses and disposed masses of materials and optimization of the machining conditions. The algorithm with the mass models is applied to the milling process planning. The process to survey the environmental data, calculate the used mass, and evaluate the alternatives is demonstrated. This demonstration illustrates the of the change of process conditions of the decision making.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.14-20
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• 1998

Cutting fluid is a factor which has big effects on both machinability and environment in machining process. The loss of cutting fluids may be reduced by the optimization of machining parameters in process planning. In this study, the environmental impact of fluid loss is analyzed. The fluid loss models in milling process are constructed with the machining parameters. The models are utilized to obtain the optimal machining parameters to minimize the fluid loss. The factors with significant effects on the fluid loss are analyzed by ANOVA test. Finally, optimal parameters are suggested considering both machining economics and environmental impact. This study is expected to be used as a part of a framework for the environmental impact assessment of machining process.