• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.10a
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• pp.731-732
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• 2009

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.83-91
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• 2006

At present, industry and researchers are looking for ways to reduce the use of lubricants because of ecological and economical reasons. Therefore, metal cutting is to move toward dry cutting or semi-dry cutting. One of the technologies is known as MQL(Minimum Quantity Lubrication) machining. This research presents an investigation into MQL machining with the objective of deriving the optimum cutting conditions for the turning process of SM4SC. To reach these goals several finish turning experiments were carried out, varying cutting speed, feed rate, oil quantity and so on, with MQL and flood coolant. The surface roughness and cutting force results of tests were measured and the effects of cutting conditions were analyzed by the method of Analysis of Variance(ANOVA). From the experimental results and ANOVA, this research proposed optimal cutting conditions to improve the machinability in MQL turning process.

• Journal of Welding and Joining
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• v.30 no.1
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• pp.51-58
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• 2012

To assess hydraulic connections between sub-components of the International Thermonuclear Experimental Reactor (ITER) diagnostic port plug, the laser welding and ablation cutting process were investigated in order to be applied the remote handling maintenance. In this study, laser ablation cutting, which vaporizes a small amount of solid material directly into gas by focusing a laser beam of high density energy, is adopted in order to overcome the limitation of the normal laser cutting technology that the head should be placed as close to the work piece as possible to blow out melt metal at a distance. Complete cutting of a work piece is obtained by repetitive multi-passes of the laser beam. The welding and cutting process were tested on the sample work pieces and finally on a prototype of a hydraulic connection module for remote handling. The results showed that this process can be a promising candidate for hydraulic connections by remote handling.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.1
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• pp.18-23
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• 2006

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has presented the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by using Tacuchi method in the design of experiment. An L9(34) orthogonal array is adopted to study the effect of adjustment parameters. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. The surface roughness of sheet metal is regarded as a quality feature. Analysis of variance is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.498-506
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• 2009

An experimental study was performed to select cutting parameters for better quality-products in hard metals such as steels. Usually, a hard metal can be cut with a rotary cutting knife and the process provides a good cutting quality result. However, the cutting machine is much sensitive in cutting conditions because of its complicated mechanism. By this reason, careful processing conditions must be taken to improve the quality of the products. This experimental study for better quality products with a rotary cutting knife was carried out with two main factors; cutting speeds and cutting and pooling forces. A two-dimensional profile measuring instrument is used to evaluate its cutting faces and the effects of processing factors are analyzed by a commercial software.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.6
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• pp.77-83
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• 2004

Cutting by a high speed laser cutting machine is one of most effective technologies to improve productivity. This paper has studied to obtain the cutting characteristics and optimal cutting conditions in a high speed feeding type laser cutting machine by Tacuchi method in design of experiments. A Lf(34) orthogonal array is adopted to study the effect of adjustment parameter. The adjustment parameters consist of cutting speed, laser power, laser output duty and assistant gas pressure. And the quality feature is selected as surface roughness of sheet metal. Variance analysis is performed in order to evaluate the effect of adjustment parameters on the quality feature of laser cutting process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.3
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• pp.39-44
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• 2005

With the development of high speed and accuracy machining, the micro-chips are formed in the machining process and broken particles are circulated with the cutting fluid. The surface roughness and accuracy of part are deteriorated because the metal particles included in the cutting fluid are embedded on machined surface. In this study, the influences of particles for the machined surface according to filtering degrees are evaluated and the embedding mechanism is suggested.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.8
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• pp.53-62
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• 1995

In recent years, the rapid development of the machine tool and tough insert has made metal removal rates increase, and automatic system without human supervision requires a higher degree reliability of machining process. Therefore the control of chips is one of the important topics which deserves much attention. The chip classification was made based upon standard deviation of the mean cutting force measured by a tool dynamometer. STS304was chosen as the workpiece which is known as the difficult-to-cut material and mainly saw-toothed chip produced, and the chip type according to the standard deviation of mean cutting force was classified into five categories in this experiment. Long continuous type chip which interrupts the normal cutting process, and damages the operator, tool and workpiece has low standard deviation value, while short broken type chip, which is favourable chip for disposal, has relatively large standard deviation value. In addition, we investigated the possibility that the chip type can be predicted analyzing the relationship between chip type and cutting condition by the trained neural network, and obtained favourable results by which the chip type can be predicted with cutting conditon before cutting process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.422-428
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• 2001

The term High Speed Machining has been used for many years to describe end milling with small diameter tools at high rotational speeds, typically 10,000 - 100,000 rpm. The process was applied in the aerospace industry for the machining of light alloys, notably aluminium. In recent year, however, the mold and die industry has begun to use the technology for the production of components, including those manufactured from hardened tool steels. With increasing cutting speed used in modern machining operation, the thermal aspects of cutting become more and more important. It not only directly influences in rate of tool wear, but also will affect machining precision recognized as thermal expansion and the roughness of the surface finish. Hence, one needs to accurately evaluate the rate of cutting heat generation and temperature distributions on the machining surface. To overcome the heat generation, we used to cutting fluid. Cutting fluid play a roles in metal cutting process. Mechanically coupled effectiveness of cutting fluids affect to friction coefficient at tool-work-piece interface and cutting temperature and chip control, surface finish, tool wear and form accuracy. Through this study, we examined the behavior of heat generation in high-speed machining and the cooling performance of various cooling methods.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.1
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• pp.1-9
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• 2001

The development of flexible automation in the manufacturing industry is concerned with production activities performed by unmanned machining system A major topic relevant to metal-cutting operations is monitoring toll wear, which affects process efficiency and product quality, and implementing automatic toll replacements. In this paper, the measurement of the cutting force components has been found to provide a method for an in-process detection of tool wear. The static com-ponents of cutting force have been used to detect flank wear. To eliminate the influence of variations in cutting conditions, tools, and workpiece materials, the force modeling is performed for various cutting conditions. The normalized force dis-parities are defined in this paper, and the relationships between normalized disparity and flank were are established. Final-ly, artificial neural network is used to learn these relationships and detect tool wear. According to proposed method, the static force components could provide the effective means to detect flank wear for varying cutting conditions in turning operation.