• 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.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.467-473
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• 2013

Diverse approaches for reducing the total energy consumption of machine tools have been introduced and developed, to cope with rapid increase of total energy costs in world-wide manufacturing industries. To realize the improvement of the energy efficiency, systematic and integrated strategies must be considered, including energy-saving design, optimized control operation and concrete evaluation of the energy efficiency. This paper proposes key enabling technologies required to improve the energy efficiency of 5-axis multi-functional machining tools, considering both of system design and operation in the real production environments. Related standardized procedures of the energy efficiency evaluation is also represented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.215-219
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• 2000

In multi-purpose lathe, the design of tilting turret slide system has on important and critical role enhance accuracy of the machining process. Tilting turret unit is traveled by 3-axis slide systems. There is a need to design this part very carefully. In this research, 3-axis sliding system with tilting turret is modeled by considering the element dividing, material proprties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of each structures such as saddle, careg, and turret are simulated by MSC/MASTRAN, for the purpose of developing the effective design.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.605-613
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• 2023

The multi-axis combined machining technology has enabled combined machining, which was difficult. However, the reality is that manufacturing costs are rising due to expensive equipment and there is a shortage of machine operation engineers. The purpose of this research is to present the optimum cutting conditions for the surface roughness when processing the inner diameter of SUS440C, which is an egg material, using a CNC automatic lathe. As a result of measuring the surface roughness, dry machining was the best at R_a0.481㎛ at a spindle speed of 4,000rpm, a feed rate of 0.05rev/min, and a cutting depth of 0.3mm. In wet machining, the highest value was R_a0.317 at a spindle speed of 2,000 rpm, a feed rate of 0.05 rev/min, and a cutting depth of 0.2 mm. The lower the feed rate, the better surface roughness appears. It was found that the feed rate had more influence than the number of revolutions and depth of cut.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.156-160
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• 2012

Recently, the demands of the large scale machine tools gradually increase to machine the large parts, such as large scale crankshaft, yaw and pitch bearings for the wind power generator and the vehicle or aircraft components. But the high technology is necessary in order to develop the huge machine tools. Furthermore, the global market of it has been monopolized by a few companies. So, we need to develop the large scale machine tools and study its core technology to rush into the increasing market. In this study, we carried out the researches for the important core technology of a multi-tasking, machine tool; a large scale 5-axis machine tool of gantry type for multi-task machining. This study is focused on the design of large size gantry type multi-axis machine. In the case of large size of machine the cross rail deflection in the X-axis is significant. To reduce the deflection due to the eccentric spindle head, a special hollow type design in the cross rail with outside ram is adapted in this study. Also, the Zig-Zag motion in the Y-axis is inevitable with the gantry geometry, which is by the un-balancing, different motion at the left and the right columns moving. We tried to reduce the influence of Zig-Zag motion using FEM with different loading conditions at the left and the right side column.

• Journal of Computational Design and Engineering
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• v.2 no.4
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• pp.261-267
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• 2015

Free-form blades are widely used in different industries, such as aero-engine and steam turbine. Blades that are damaged during service or have production deficiencies are usually replaced with new ones. This leads to the waste of expensive material and is not sustainable. However, material and costs can be saved by repairing of locally damaged blades or blades with localized production deficiencies. The blade needs to be further machined after welding process to reach the aerodynamic performance requirements. This paper outlines an adaptive location approach of repaired blade for model reconstruction and NC machining. Firstly, a mathematical model is established to describe the localization problem under constraints. Secondly, by solving the mathematical model, localization of repaired blade for NC machining can be obtained. Furthermore, a more flexible method based on the proposed mathematical model and the continuity of the deformation process is developed to realize a better localization. Thirdly, by rebuilding the model of the repaired blade and extracting repair error, optimized tool paths for NC machining is generated adaptively for each individual part. Finally, three examples are given to validate the proposed method.

• Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.151-160
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• 2016

Cutter-workpiece engagement (CWE) is the instantaneous contact geometry between the cutter and the in-process workpiece during machining. It plays an important role in machining process simulation and directly affects the calculation of the predicted cutting forces and torques. The difficulty and challenge of CWE determination come from the complexity due to the changing geometry of in-process workpiece and the curved tool path of cutter movement, especially for multi-axis milling. This paper presents a new method to determine the CWE for general milling processes. To fulfill the requirement of generality, which means for any cutter type, any in-process workpiece shape, and any tool path even with self-intersections, all the associated geometries are to be modeled as triangle meshes. The involved triangle-to-triangle intersection calculations are carried out by an effective method in order to realize the multiple subtraction Boolean operations between the tool and the workpiece mesh models and to determine the CWE. The presented method has been validated by a series of case studies of increasing machining complexity to demonstrate its applicability to general milling processes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.86-92
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• 2021

As interest and demand for high value-added industries, including the global automobile and aerospace industries, have increased recently, demand for line centers with excellent performance that can respond to the production system for producing high value-added products is also rapidly increasing. A line center improves productivity based on the installed area using a multi-spindle compared to a conventional machining center. However, as the number of spindles increases, the weight increases and results in structural problems owing to the heat and vibration generated by each spindle. Therefore, it is necessary to improve machining precision through the structural improvement of the line center. This study presents research on the stabilization design of the line center through structural stability analysis through structural analysis to develop a compact multi-axis line center. An optimization model of the line center has been proposed to improve the processing precision and increase the rigidity by performing weight reduction based on the structural analysis results.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.1
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• pp.34-38
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• 2008

The surface texture of a product is generally produced by etching or sandblasting. However, these techniques have problems related to repeatability and environmental pollution. Since current milling machines can produce small parts at the micrometer or nanometer level, the resolution of milling exceeds the manufactured dimensions of the surface texture produced by etching or sand-blasting. A method for generating surface texture by milling is proposed and demonstrated. The proposed method was demonstrated by actual milling using a three- or five-axis control machine, and the machined surface texture was measured with an interferometer to allow comparison with the designed shape. The measurement results demonstrate that the proposed method can generate a wide-area surface texture with good machining repeatability.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.188-192
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• 2000

In multi-purpose lathe, the design of tilting turret slide system has an important and critical role to enhance accuracy of the machining process. Tilting turret unit is traveled by 3-axis slide systems. There is a need to design this part very carefully. In this research, 3-axis sliding system with tilting turret is modeled by considering the element dividing, material properties, and boundary conditions using MSC/PATRAN. Mode and frequency analysis of each structures such as saddle, careg, and turret are simulated by MSC/NASTRAN, for the purpose of developing the effective design. The results of mode analysis and frequency analysis are visualized with PATRAN, and the mothod which can solve the resornance problem by eigenvalues and eigenvectors of each axe is developed as well.