• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.439-444
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• 2004

A new efficient intelligent machining strategy named the Steepest Directed Tree method is presented in this study, which makes surface model discrete with triangulation meshes and the cutter paths track along the tree directions. In order to formulate these algorithms practically, it is deduced the multi-stage machining approach of uncut volume caused by cutter gouging in the course of milling using flat end mill. It is systematized the checking process the cutter interference by grouping the 6 kinds of gouging types, which yields the environment of connectivity data lists including CL-data, and then the multi-stage machining strategy, that minimizes uncut area by continuously sequencing the generative subsequent CL-paths, is shamed to determine the second tool path for the next uncut area and to compose the operating multi-stage cutting processes. The completed machining system of curved surfaces is evaluated by testing the practical machining experiments which have various kinds of shape conditions.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.251-259
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• 2010

It is presented in this study a new efficient intelligent machining strategy, which can be used to remove the uncut volume at the boundary region of curved surfaces caused by cutter interference. The geometric form definitions and recognition of topological features of the surface triangulation mesh are used to generate cutter paths along successive and interconnected steepest pathways, that minimize the cusp height left after flat end milling. In order to machine the uncut volume gradually, the z-map cutter centers are adjusted to avoid cutter interference for the 6 kinds of avoidance types. And then, the generative subsequent paths are sequenced to determine the second step cutter paths for the next uncut volume. For the 2 kinds of test models with convex and concave surface region, the implemented software algorithm is evaluated by investigating the residual swelling of uncut volume for each machining step.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.161-167
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• 1996

In five-axis milling, optimal CL-data (cutter location data) should be generated to have advantages over three-axis milling in terms of accuracy and efficiency. This paper presents an algorithm for generating collision-free CL-data for five-axis milling using potential energy method. By virtually charging the cutter and part surfaces with static electricity, global collision as wells as local interference is eliminated. Additionally, machining efficiency is improved by minimizing the curvature difference between the part surface and tool swept surface at a CC-point (cutter contact point) simultaneously.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.74-84
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• 1994

This paper discusses a method to generate the tool path for NC machining of automobile panel dies. The source data representing a panel die may be generated from digitizing machines, other CAD/CAM systems via IGES files, of compound surface models. From the source data, three types of interferencefree tool paths are generated automatically ; a parallel (Cartesian), an isometric, and a pencil cutting tool path. For the interference-free tool path, a polyhedral model composed of several triangles, and an 'offset triangle' approach are exploited. Finally, some practical examples are illustrated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.233-234
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.188-192
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• 1994

This paper presenta new method for tool interference acoidance using rectanguar approximation in NC machining of scuptured surface. The procedure of algorithm for approximation of sculptured surface to rectangular surface is described. Using this algorithm, we can check concave, convex, and side interference region and avoid these interferenes.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.5 s.98
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• pp.11-18
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• 1999

Recently high speed machining is being studied actively to reduce machining time and to improve machining precision. To perform efficient high speed machining, evaluation of high speed machinability must be studied preferentially and it can be identified by investigation of cutting force. To measure cutting forces in high speed machining, dynamometer which has high natural frequency was newly designed using 3-axes piezo force sensor. For newly designed dynamometer, calibration is conducted with sensitivity of force sensor modulated and proper preload and interference force are investigated experimently. Also, cutting force signals of newly designed dynamometer are compared with those of conventional one in high speed cutting experiment and its superiority is confirmed. Then using newly designed dynamometer, high speed machinability is evaluated about cutting force and tool wear in various cutting conditions.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.2
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• pp.51-62
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• 1998

In this paper, a CAD/CAM system for 5-axis machining of model propeller is introduced. This system has been developed under the environment of personal computer and Windows NT. In order to enhance the productivity, existing text-based design S/W was integrated into this graphic-based system. Non-Uniform Rational B-Spline method is used to represent the sculptured surface of propeller blades and hub using point data, and surface blending between blade and hub is realized in this system. For 5-axis machining of sculptured surface, tool/work collision and interference are checked and inverse kinematic analysis is performed to make NC data. In addition, tool and workpiece are animated on the PC monitor by preparing NC verification module. Finally, optimal cutting conditions are determined empirically and those cutting conditions are integrated into this S/W so that the whole process from design to machining can be done automatically.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.9
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• pp.53-61
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• 2000

The manufacture of a marine propeller typically requires long lead time to generate 5-axis tool path. Hence it may take several weeks to manufacture a satisfactory propeller with a general purpose CAD/CAM system. In this research a dedicated 5-axis CAD/CAM system for machining marine propellers has been developed, The system employs various methods to enhance the productivity : interference-free tool path generation employing check vectors and optimum cutter size determinants. In addition an iterative NURBS modeling technique is used to improve the accuracy of the modeled surface and effective cutting conditions are determined and recommended empirically to increase the productivity. The proposed CAD/CAM system has been implemented with C++ and OpenGL graphic library on the Windows system. The system validation and sample results are also given and discussed.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.116-123
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• 1991

사각 patch로써 곡면을 표현하는 일반적인 CAD/CAM시스템에서 NC가공을 위한 가공데이타를 생성할 때에는 보통 두가지 가공방법을 사용한다. 그 하나는 isoparametric가공이며 다른 하나는 cartesian가공이다. 금형부에서 사용하는 CAD/CAM시스템인 catia에서도 위의 두가지 NC가공방식을 모두 사용할 수 있다. 그런데 isoparametric가공의 경우, 공구간섭처리를 위한 곡면모델의 수정에 많은 시간이 소요되며, NC프로그래머의 실수로 인한 가공불량 발생의 가능성도 크고 황삭가공에도 매우 불편하다. 이러한 문제는 cartesian가공방법으로 해결이 가능하며, catia의 경우 parallel plane machining기능이다. 그러나 이 기능을 catia에서 통상적인 방법으로 modeling된 곡면에 적용할 경우에 그 신뢰성이 매우 낮다. 따라서 금형부에서는 그 방식은 cartesian으로 하되 신뢰성이 높은 NC가공 S/W를 개발하게 되었다. 이는 catia시스템에서 modeling된 곡면으로부터 NC 가공데이타를 생성하는 S/W로서 VS Fortran으로 작성되었다.