• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.944-947
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• 2000

Sculptured surface machining plays a vital role in the process of bring new products to the market place. A great variety of products rely on this technology for the production of the dies and moulds used in manufacturing. And, the use of CNC machines and CAD/CAM system has become a vital parts of product development process. The propose of this study is to investigate the effect of cutting parameters on the machinability such as surface roughness and cusp generated in the machining of sculptured surface on a three-axis CNC machining center using the CAD/CAM system. Experimental result showed that: In step down cutting, as the inclined angle of surface became smaller, the cusp height appeared higher. On the other hand, in step over cutting, as the inclined angle of surface became larger, the cusp height appeared higher. In the point of precision machining, step over cutting was more effective. For the minimization of cusp height, step down cutting was effective in larger inclined surface, but step over cutting in smaller inclined surface.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.4
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• pp.31-36
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• 2002

A continuous tool-path, that is to cut continuously with the minimum number of cutter retractions during the cutting operations, is developed in order to minimise the fluctuation of cutting load and the possibility of chipping on the cutting edge in HSM (high-speed machining). This algorithm begins with the offset procedure along the boundary curve of the sculptured surface being machined. In the of offset procedure, the offset distance is determined such that the scallop height maintains a constant roughness to ensure higher levels of efficiency and quality in high-speed machining. Then, the continuous path is generated as a kind of the diagonal curve between the offset curves. This path strategy is able to connect to neighbor paths without cutter retractions. Therefore, the minimum tool retraction tool-path can be generated And, it allows the sculptured surface incorporating both steep and flat areas to be high-speed machined.

• Journal of Korean Institute of Industrial Engineers
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• v.9 no.2
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• pp.27-35
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• 1983

This paper describes a procedure of generating economic cutter-location(CL) data for the machining of sculptured surfaces on a multi-axis NC milling machine. Measures of economy are the machining time (cutter move distance) and the length of NC tape (number of CL data points). The presented procedure minimizes both the number of CL data and the total distance of cutter moves, for a given cutter (spherical end-mill) size and parameteric cutting direction, while satisfying given tolerance requirements. The procedure has been implemented in FORTRAN for a smooth composite Bezier surface. The maximum allowable cutter size is calculated by the program so that a user can choose a cutter size. CL data can be generated in both parametric directions u and v. Experimental results show that there are significant differences between the parametric directions, and that cutter size should be as large as possible in order to minimize the cutting time and NC tape length.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.347-350
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• 2003

Many researches on the prediction of cutting forces of ball-end mil is have been achieved since before several decades ago. These kinds of researches have been concentrated on the study on how to make the prediction equations for the cutting forces based on 2-D cutting experimentation. The results of them were really good and impressive. But it's not proper to practical uses for industrial fields, because if sculptured surface were to be machined, then it would be very difficult to understand the complicated kinematical interaction between the sculptured surface and the flutes of a ball-end mill. So, we propose the method for solving these kind of problems using existed commercial CAD/CAM software; Unigraphics. Furthermore, the modification of tool path which is done off line is offered to increase the precision of cutting.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.1
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• pp.5-14
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• 1995

An optical measurement method of three dimensional surface profiles which is named the slit beam projection is suggested and practically implemented. This method is intended especially for noncontact and fast digitization of sculptured surfaces for CAD modeling and die manufacturing. Its basic principles are based on geometric optics. Deatiled optical principles and an sub-pixel image processing technique to enhance the measuring resolutions are described in this study. The measuring performances of the slit beam projection are presented and discussed to demonstrate that an actual measuring accuracy of below .+-. 0.2mm can be achived over the whole measuring range(500mm*300mm*200mm)

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.1
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• pp.92-100
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• 1994

For generating NC machining data automatically, it is important to handle computer models such as geometric shape data including engineering specifications for the mechanical part to be manufactured. We proposed unique CAM system for a personal computer that can define the geometric shape in an ease manner and machine the sculptured surfaces of a mold cavity. In this paper, the theoretical basis of generation of high precision machining data for a mold cavity is obtained. The first is geometric modelling, and the second is high precision machining with an optimized tool path algorithm satisfying given tolerance limits. Especially, the bicubic Bezier basis function is adopted for a geometric modelling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.721-724
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• 2000

This paper presents a prediction of tool deflection and resulting machining error fur sculptured surface productions in the ball-end milling process. Due to the different materials and the dimensions of the tool holder and cutter, a cantilever hem model with three uniform sections is proposed fur the tool deflection model. The ability of this model has been verified by a machining experiment. In this study, cutting force and machining error are investigated. This paper provides the prediction of machining error for sculptured surface to improve machining quality for industrial application.

• Korean Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.192-200
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• 1998

Even though most die-maker are using CAD/CAM systems rout NC tool-path generation, “front-end”CAD/CAM technologies have not been fully adapted to sculptured surface machining(SSM) nor are sufficiently utilized in die shops. This gap between die-making industry and CAD/CAM community persists mainly because of the lack of a SSM-process model through which the two groups communicate with each other. Proposed in this paper is a model of SSM-processes which is built around the concepts of machining stages, unit machining operations, and each machining stage is decomposed into a sequence of unit machining operations(UMOs). Identified in the paper are five machining stages and 17 types of UMO. Based on the framework of the proposed model, an example of inner-panel stamping-die machining processes is described in detail.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.395-395
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• 1993

• 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.