• Proceedings of the Korean Operations and Management Science Society Conference
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• 1992.04b
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• pp.299-308
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• 1992

Determining tool-approach directions is an important issue when an effort is made to transfer CAD data into manufacturing automatically. An algorithm is developed to determine whether a given part can be machined on a three-axis milling machine. lf a set of feasible tool-approach directions exists for a sculptured surface, the NC tool path and G-codes for machining the surface on a three-axis milling machine can be generated automatically by an NC tool path generation algorithm. The algorithm can be used for orientation and fixturing of the workpiece for interference free machining. The algorithm can also be applied to checking the translational separability of polyhedral parts in automatic assembly.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.11
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• pp.114-125
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• 1997

This paper presents a method that automatically recognizes dimension sets from the mechanical drawings, and that classifies 6 types dimension sets according to functional purpose. In the proposed method, the object and closed-loop symbols are separated from the character-free drawings. Then object lines and interpretation lines are vectorized. And, after recognizing dimension sets(consistings of arrowhead, shape line, tail lines, extension lines, text-string, and feature control frame), we classify recognized dimension sets as horizontal, vertical, angular, diametral, radial, and leader dimension sets. Finally the proposed method converts classified dimension sets into AutoCAD data by using AutoLisp language. By using the methods of geometric modeling, the proposed method readily recognized and classifies dimension sets from complex drawings. Experimetnal results are presented, which are obtained by applying the proposed method to drawings drawn in compliance with the KS drafting standard.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.118.5-118
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• 2002

To apply induction hardening method to a press die having 3-D free surface, the induction hardening tool moves on a press die above 1～2mm gap with constant velocity. Since the induction hardening process requires its own hardening path for each die, a direct teaching method which generates working path directly guided by operators is more suitable than an offline method using CAD/CAM data. The direct teaching apparatus in this work includes a teaching tool with a force/torque sensor and data processing computer to finally generate robot's Induction hardening program , in direct teaching operation, an operator teaches working path maintaining contact with surface of press die by holding...

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.895-898
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• 2001

This paper presents an optimization cutting speed(OCS) program developed to improve the machining precision and tool life in high speed machining using ball end milling. This program optimized the cutting speed that is changing at any time in free surface machining of an automobile part like a connecting load die. The technique of optimization cutting speed makes the CAD/CAM-generated NC code go through a reverse post process, conducts cutting simulation, and obtain the effective tool diameter of the ball end milling. Then it changes the spindle revolution to within the range of critical cutting speed fit for the material of the workpieces depending upon the effective tool diameter. In this study, the machining precision and tool life were compared for the two connecting load dies processed using the general cutting method and the proposed optimization cutting speed technique, respectively.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.1
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• pp.15-22
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• 2005

This research presents modeling of a functional surface that is constructed with a free-formed surface. The modeling of functional surfaces, being introduced in this paper, adopts a modified B-spline that utilizes an approximating technique. The modified B-Spline is constructed with altered control vertices. It is applied to measure the surface of an impeller blade. This research builds an algorithm accepting inputs of measured points. Generating the cutter-paths for NC machining employs the model of the constructed surfaces. The machined surfaces that are generated in several cases are compared with each other in the aspect of machining accuracy.

• International Journal of CAD/CAM
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• v.6 no.1
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• pp.157-166
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• 2006

In order to model blending surfaces with curvature continuity, in this paper we apply sixth order partial differential equations (PDEs), which are solved with a composite power series based method. The proposed composite power series based approach meets boundary conditions exactly, minimises the errors of the PDEs, and creates almost as accurate blending surfaces as those from the closed form solution that is the most accurate but achievable only for some simple blending problems. Since only a few unknown constants are involved, the proposed method is comparable with the closed form solution in terms of computational efficiency. Moreover, it can be used to construct 3- or 4-sided patches through the satisfaction of continuities along all edges of the patches. Therefore, the developed method is simpler and more efficient than numerical methods, more powerful than the analytical methods, and can be implemented into an effective tool for the generation and manipulation of complex free-form surfaces.

• International Journal of CAD/CAM
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• v.3 no.1_2
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• pp.31-40
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• 2003

In this paper, first order slice height calculation in Laminated Object Manufacturing (LOM) of free form surfaces is done with two different considerations: that a) the cutter trajectory is oriented in the direction of local absolute maximum more in number when compared to the case where the cutter trajectory is contained in the normal vertical section (NVS). However, it would help in achieving higher form accuracy of the final part because it would be a form of worst-case check. For the second proposed strategy, least number of slices results, thereby reducing overall build time drastically.

• ETRI Journal
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• v.23 no.2
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• pp.85-95
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• 2001

The surface modeling capability of CAD systems is widely used to design products bounded by free form surfaces and curves. However, the surfaces or curves generated by popular data fitting methods usually have shape imperfections such as wiggles. Thus, fairing operations are required to remove the wiggles, which makes the surfaces or curves smooth. This paper proposes a new method based on the wavelet transform for fairing the surfaces or curves while preserving the continuity with adjacent surfaces or curves. The wavelet transform gives a hierarchical perspective of the surfaces and the curves, which can be decomposed into the overall sweep and details, i.e., local deviations from sweep like the wiggles. The proposed fairing method provides a similar effect on the mathematical surface as that of the grinding operation using sandpaper on the physical surface.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.88-89
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• 1991

For the micro-lithography using a KrF excimer laser beam(λ=0.248${\mu}{\textrm}{m}$) a mirror system consisting of four spherical surfaces with reduction magnification 5$\times$ is designed. Initially the aplanat condition of the mirror system is considered. And for the further improved performance of the system the distortion free condition and flat field condition within Seidel 3rd order aberrations are added to the above condition. During the process of designing the computer-aided optimization technique is extensively employed. The spherical aberration, coma, field curvature and distortion of the optimized four-spherical mirror system are removed to the diffraction limit, and residual astigmatism and off-axial vignetting are not corrected enough.

• Transactions on Electrical and Electronic Materials
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• v.18 no.1
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• pp.25-29
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• 2017

This paper presents a unique pressure sensor design for environmental applications. The design uses a new geometry for a multi bossed beam-membrane structure with a SOI (silicon-on-insulator) substrate and a mechanical transducer. The Intellisuite MEMS CAD design tool was used to build and analyze the structure with FEM (finite element modeling). The working principle of the multi bossed beam structure is explained. FEM calculations show that a sensing diaphragm with Mises stress can provide superior linear response compared to a stress-free diaphragm. These simulation results are validated by comparing the estimated deflection response. The results show that, the sensitivity is enhanced by using both the novel geometry and the SOI substrate.