• Proceedings of the KSME Conference
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• 2001.06c
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• pp.116-121
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• 2001

Verification of tool collision is an important issue in die and mold machining. In this paper three functions of verification are schematically explained based on Z-Map model. The first function is getting a collision-free region when a tool assembly and a part surface model are given. The second function estimates the shortest length of cutter shank with that the tool cuts all of a region without collision. The last one is cutting simulation considering all parts of tool assembly as well as cutter blade. Those functions can be easily implemented by using several basic operators of Z-Map model which are explained also. Proposed approaches have enough accuracy to verify collision in reasonable computing time.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.6
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• pp.35-42
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• 2002

Verification of tool collision Is an important issue in die and mold machining. In this paper three functions of verification for 3-axis milling machining are schematically explained. Operators of geometric models are explained at first, which will be used in the functions of verification. The first verification function is getting a collision-free region when a tool assembly and a part surface model are given. The second function estimates the shortest length of cutter shank with that the tool cuts all of a region without collision The last one is cutting simulation considering all parts of tool assembly as well as cutter blade. Proposed approaches can be easily implemented by using several basic operators of geometric model. An example to calculate collision-free region is presented also.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.125-128
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• 1997

They use a Ball End-mill in order to manufacturing sculptured surface when making metal mold, mold, cars and aircraft. In the work of a Ball End-mill case, customers do not often satisfied with manufacturing precision. Eventually, they have to re-work for the purpose of meeting manufacturing precision. There are resulted in lots of loss, whereby, in terms of both time and costs. The reasons of tolerance reducing manufacturing precision are thermal strain, the surface is damaged because of increasing cutting force and tool wear, tool deflection etc.. We focus on, however, manufacturing precision caused due to deflection of tool.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.822-826
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• 1997

근래에 들어, 금형생산 시간의 단축과 고정밀도의 제품을 생산하기 위해 실가공전의 설계단계에서 금형 데이터를 수치적으로 검증할 필요가 높아지고 있다. 기존의 저가형 CAM시스템에서 사용된 경로표시법으 로는 이러한 검증이 불가능하기 때문에 새로운 방법의 도입이 필요하며 모의가공 형상의 표현에서도 비매 개변수형 곡면을 이영하는 방법이 널리 사용되고 있다. 본 연구는 3축 금형가곡에 사용되는 볼앤드밀, 평 엔드밀 공구에 대해 Z-map을 기반으로 절삭부위를 비매개변수형 곡면으로 모델링하여 모의가공을 수행하 고자 한다. 또한, 새로운 backeting영역지정 방법을 사용하여 모의가공의 효율을 높였다.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.39-54
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• 1997

This paper presents four process models for machining processes : 1) an economical mathematical model of machining process, 2) a prediction model for surface roughness, 3) a decision model for fuzzy cutting conditions, and 4) a judgment model of machinability with automatic selection of cutting conditions. Each model was developed the economic machining, and these models were applied to theories widely studied in industrial engineering which are nonlinear programming, computer simulation, fuzzy theory, and neural networks. The results of this paper emphasize the human oriented domain of a nonlinear programming problem. From a viewpoint of the decision maker, fuzzy nonlinear programming modeling seems to be apparently more flexible, more acceptable, and more reliable for uncertain, ill-defined, and vague problem situations.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2000.11a
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• pp.7-9
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• 2000

• Proceedings of the Korean Society of Laser Processing Conference
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• 2002.11a
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• pp.37-40
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• 2002

• Wind and Structures
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• v.35 no.5
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• pp.309-322
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• 2022

Due to the complex terrain around high-speed railways, the windbreaks were established along different landforms, resulting in irregular windbreak transition regions between different subgrade infrastructures (flat ground, cutting, embankment, etc). In this paper, the effect of a windbreak transition on the wind flow around railways subjected to crosswinds was studied. Wind tunnel testing was conducted to study the wind speed change around a windbreak transition on flat ground with a uniform wind speed inflow, and the collected data were used to validate a numerical simulation based on a detached eddy simulation method. The validated numerical method was then used to investigate the effect of the windbreak transition from the flat ground to cutting (the "cutting" is a railway subgrade type formed by digging down from the original ground) for three different wind incidence angles of 90°, 75°, and 105°. The deterioration mechanism of the flow fields and the reasons behind the occurrence of the peak wind velocities were explained in detail. The results showed that for the windbreak transition on flat ground, the impact was small. For the transition from the flat ground to the cutting, the influence was relatively large. The significant increase in the wind speeds was due to the right-angle structure of the windbreak transition, which resulted in sudden changes of the wind velocity as well as the direction. In addition, the height mismatch in the transition region worsened the protective effect of a typical windbreak.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.2
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• pp.3-9
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• 2004

The main objectives of this paper are to determine optimum cutting conditions using experimental design method to manufacture pedicle screws. Generally, titanium alloys are known as difficult-to cut materials. In the machining of titanium alloy, high cutting temperature and strong chemical affinity between the tool and the work material are generated because of Its low thermal conductivity and chemical reactivity. Such phenomenon cause increase of tool wear and deterioration of surface quality. Thus, in this paper, required experimental investigations are performed to evaluate the machinability of titanium materials With tungsten carbide tools Required simulation and experiments are performed, and the results are investigated.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.86-92
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• 2016

Mechanical milling, in association with electrical discharge machining (EDM) for hybrid machining, is presented in this paper. An end mill cutting tool, an electrode of the EDM, was used for the system. That means that some parts were cut by the mechanical cutting process and others by the EDM. The possibility of combining both processes was simulated with the cutting simulation software. In addition, the machining reality was verified by measuring the electrical signal from the EDM power supply, which was measured in time and frequency domains. From this initial research, the hybrid machining system proposed in this paper appears to be well suited for difficult to cut material processing.