• Journal of the Korean Society for Precision Engineering
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• v.23 no.9 s.186
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• pp.156-163
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• 2006

The purpose of this study is to improve the machining of free-formed NURBS surfaces using newly defined G-codes which can directly deal with shapes defined from CAD/CAM programs on a surface basis and specialize in rough and finish cut. To this purpose, a NURBS surface interpolation system is proposed in this paper. The proposed interpolation system includes online tool-path planning, real-time interpolation and feedrate regulation considering an effective machining method and minimum machining time all suitable for unit NURBS surface machining. The corresponding algorithms are simultaneously executed in an online manner. The proposed NURBS surface interpolation system is integrated and implemented with a PC-based 3-axis CNC milling system. A graphic user interface (GUI) and a 3D tool-path viewer which interprets the G-codes for NURBS surfaces and displays whole tool-paths are also developed and included in our real-time control system. The proposed system is evaluated through actual machining in terms of size of NC data, machining time, regulation of feedrate and cutting force focused on finish cut in comparison with the existing method.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.411-415
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• 2004

In this paper, a double artificial neural network (ANN) approach and the efficient machining database building scheme are presented for the prediction of surface roughness in high-speed machining. In this approach, 4 machining parameters and used for the prediction of cutting force components, and the combinations of 4 parameters and the predicted cutting force components are finally used for the prediction of surface roughness. The experimental results comparing the these results with the predicted values using simple 4 input nodes have been also investigated to verify the effectiveness of the proposed approach.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.12
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• pp.100-106
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• 2021

This paper presents a study on the improvement of the machining quality of sculptured-surfaces of molds according to the shape and posture of the tool. In the existing 3-axis machining, the methods using the ball end-mill and radius end-mill were analyzed for various cutting patterns and compared with those of the 5-axis machining. It was observed that the 5-axis machining using a ball end-mill obtained the finest surface roughness, and for the 3-axis machining, the optimal results were obtained for the one-way machining using a radius end-mill.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.3
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• pp.54-61
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• 2007

Machining processes produce high accurate metallic parts in metal working industries. Lubrication for machining enhances quality of machined surface and it prolongs the life of cutting tools. Since lubricant is poisonous to human body and environment, it causes occupational diseases for workers and air pollution in environment. Because of these problems generated, developed countries do not permit the excessive usage of lubricant in machining shops. This research focuses on the development of MQL machining technique that consumes minimal amount of lubricant, which reduces possible outbreak of occupational diseases and air pollution. This research sets experimental equipments for MQL machining. Experiments for this study are designed with major machining parameters in MQL. Through the analysis of experiments, this paper presents the optimal machining parameters.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.04b
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• pp.157-163
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• 1995

This paper presents an algorithm to deternine the tool path height for rough machining of sculptured surface. To minimize rough machining of sculptured surface, it is necessary to determine the tool path heights of contour planes. the proposed algorithm searches for the height at which maximum metal removal rate is obtained. This bisection method is accomplished until all shoulder heights are within roughing tolerance. The machining experiment demonstrates the superiority of the algorithm presented in this thesis.

• Journal of the Korean Wood Science and Technology
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• v.32 no.3
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• pp.1-7
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• 2004

The application of abrasive-assisted high energy water-jet was investigated as a possible new method of cutting wood. In this study the maximum cutting speeds for species of various wood density were determined and water-jet machining characteristics were investigated for sixteen Korean domestic species. The maximum cutting speed ranged from 200 to 750 mm/min. The results indicate that wood density affects machining characteristics such as maximum cutting speed, surface roughness, and kerf width. Roughness of surface generated increased and kerf width decreased as penetration depth increased.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1348-1352
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• 2004

An aspherical lens in information technology has been increased in order to enhance the optical performances. There are two kinds of approaches to machine the aspherica surface is generally conducted by the diamond turning machine, precision grinding machine, and polishing machine. This technique, however, has a problem which needs an expensive and high precision machine in order to increase the surface roughness and the machining accuracy. In this paper, a machine, which is able to machine the aspherical surface, was developed to decrease the cost. Also, the machining of the aspherical surface using a cone was carried out experimentally in order to compare the experiment with the simulation. The results showed that the machining experiments of the aspherical surface by using the titled cone were in accordance with the simulation.

• Journal of the Korea Society for Simulation
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• v.8 no.1
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• pp.19-33
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• 1999

The fundamental issues to evaluate machine tools performance through simulation pertain to the physical models of the machine tool itself and of process while the practical problems are related to the development of the modular software structure. It allows the composition of arbitrary machine/process models along with the development of programs to evaluate each state of machining process. Surface roughness is one of the fundamental factors to evaluate machining process and performance of machine tool, but it is not easy to evaluate surface roughness due to its tribological complexity. This paper presents an algorithm to calculate surface roughness considering cutting geometry, cutting parameters, and contact dynamics of cutting between tool and workpiece as well as tool wear in turning process. This proposed algorithm could be used in the designed virtual machining system. The system can be used to evaluate the surface integrity of a turned surface during the design and process planning phase for the design for manufacturability analysis of the concurrent engineering.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.3
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• pp.100-106
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• 1999

Owing to the complexity of electrical discharge machining (EDM) phenomenon, it is very difficult to determine optimal machining parameters fer improving machining performance. This paper proposes a methodology for determining optimal electrical discharge machining parameters, which is maintaining suitable current density for increasing productivity or improving surface roughness. Machining area is closely related on optimal machining parameters in electrical discharge machining process, so calculation of machining area is needed in order to determine optimal machining parameters. In this study machining area, which is corresponding to the machining position, is calculated from intersection curves between the tool surface and a horizontal plane.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.1
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• pp.186-195
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• 2002

The mechanism of micro machining of reacted layer on silicon surface were proposed. The depth of reacted layer and the change of mechanical property were measured and analyzed. Depth of hydrated layer which is created on the surface of silicon by potassium hydrate was analyzed with SEM and XPS. The decrease of the micro victors hardness of silicon surface was shown with the increase of the concentration of potassium hydrate and the change of the dynamic friction coefficient by chemical reacted layer was measured due to the readiness of machining. The experiment of groove machining was done with 3-axis machine with constant load. With chemical mechanical micro machining the surface crack and burrs generated by both brittle and ductile micro machining were diminished. And the surface profile and groove depth was shown in accordance with the machining speed and reaction time with SEM and AFM.