• Korean Journal of Computational Design and Engineering
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• v.9 no.1
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• pp.35-43
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• 2004

It is well known that the five-axis machining has advantages of tool accessibility and machined surface quality when compared with conventional three-axis machining. Traditional researches on the five-axis tool-path generation have addressed interferences such as cutter gouging, collision, machine kinematics and optimization of a CL(cutter location) or a cutter position. In the paper it is presented that optimal CL data for a face-milling cutter moving on a tool-path are obtained by incorporating TSS(tool swept surface) model. The TSS model from current CL position to the next CL position is constructed based on machine kinematics as well as cutter geometry, with which the deviation from the design surface can be computed. Then the next CC(cutter-contact) point should be adjusted such that the deviation conforms to given machining tolerance value. The proposed algorithm was implemented and applied to a marine propeller machining, which proved effective from a quantitative point of view. In addition, the algorithm using the TSS can also be applied to avoid cutter convex interferences in general three-axis NC machining.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1991.10a
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• pp.124-130
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• 1991

5-axis NC machining of sculptured surface using non-ballendmill cutters (eg. facemilling cutters) is widely used in the machining of turbine blades and marine propellers. Since there are more degrees of freedom in 5-axis machining than in 3-axis machining, generating "optimum" cutter paths and finding desirable cutter positions become very important in order for an efficient use of 5-axis NC machines. Also critical in 5-axis NC machining are collision avoidance, gouging checking, and efficient kinematic solutions. In this paper we discuss the above issues in generating 5-axis CL data. They are : kinematics modeling of NC machine; inverse kinematics solution; interference between machine component and surface; cutter gouging. A unique search method for obtaining optimal CL data is proposed. The proposed method has been successfully implemented in the machining of marine propellers on a dual 5-axis (ie, 9-axis) NC machine.C machine.

• 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.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.1
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• pp.78-87
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• 2001

This paper deals with the study on the cutting characteristics in ball-end milling process. First of all, the effects of the geometric cutting conditions such as the cutting speed, feedrates and the path interval on the surface integrity were evaluat-ed by the analytical and the experimental approaches. Secondly, the cutting mechanism model was developed to predict the cutting force accurately. It is possible for the proposed model to predict the shape error, estimate system stability and build the reliable adaptive control system. A large amount of experimental set are performed to show the validities of the proposed theories and to investigate the effect of cutting geometry such as rubbing effects, burr effects and etc.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.53-60
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• 2002

Recently, the development of aerospace and automobile industries brought new technological challenges, related to the growing complexity of products and new geometry models. High speed machining using 5-Axis milling machine is widely used for 3D sculptured surface parts. 5-axis milling of turbine blade generates the vibration, deflection and twisting caused from thin and cantilever shape. So, the surface roughness and the waviness of workpiece are not good. In this paper, The effects of cutter orientation and lead/tilt angle in 5-Axis high speed ball end-milling of turbine blade were investigated to improve the geometric accuracy and surface integrity. The experiments were performed at lead/tilt angle $15^{\circ}$ of workpiece with four cutter directions such as horizontal outward, horizontal inward, vertical outward, and vertical inward. Workpiece deflection, surface roughness and machined surface were measured with various cutter orientations such as cutting direction, and lead/tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle.

• 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.18 no.2
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• pp.84-89
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• 2001

In recent years, there is increasing demand of esthetic design and complex function in aerospace, automobile and die/mold industry, which brings into limelight high-precision, high-efficient machining of sculptured surface. This paper deals with the establishment of the optimal tool path on free form surface in high speed ball end milling. Ball end milling is widely used for free form surface die and mold. In this machining, the cutting direction was changed with tool path. The cutting characteristics, such as cutting force and surface form are varied according to the variation of cutting directions. In this paper, the optimal tool path with down cutting in free form surface cutting is suggested.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.6
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• pp.105-112
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• 1999

In this paper we deal with tool interference problem in the case of compound surface machining. A new tool interference detection and correction method based on the envelope of the tool path is suggested to identify and correct the tool interference - not only within the local path of tool movement, but also outside of the tool path. Therefore, the developed strategy can be used to check the possible interference in any region of the surface. In order to analyze quantitatively the milled surface error produced by the tool interference, improved surface prediction model is also suggested in cutting process by general cutters. The effectiveness of the proposed method is demonstrated through simulation study.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.53-57
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• 2009

There are technical requirements to manufacture large size functional parts with not only simple geometries like a flat or spherical surface but also sculptured geometries. In addition, the required machining accuracy for these parts is becoming more severe. In general, the form accuracy of machined parts is determined by the relative position between workpiece and tool during machining process. To improve machining accuracy the relative position errors should be maintained within the required accuracy. This study deals with the estimation and calibration of depth of cut using the AE signal in micro-machining. Also, this sensing technique can be applied to detect the initial contact between workpiece and tool.

• 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.