• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.10a
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• pp.230-235
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• 2000

In this paper, a surface generation model is presented to simulate surface roughness profile in turning operation. The simulation model takes into account the effect of tool geometry, process parameters, rotational errors of spindle, and the relative vibration between the cutting tool and workpiece. The surface roughness profiles are simulated based on the surface-shaping system. The model has been verified by comparing the experimental values with the simulation values. It is shown that the surface simulation model can properly predict the surface roughness profile.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.2
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• pp.1-16
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• 1991

This paper deals with some critical activities of CAPP system such as generation of part description database, part feature recognition, process and operation selection, and sequencing method for turning operation of symmetric rotational parts. The part description database is generated by data conversion module from CAD data, and the part feature is recognized by using both pattern primitives and feature recognition rules. Machining processes and operations are selected based on machining surface features and its sequence is determined by rules acquired from process planning expert. AutoCAD is employed as CAD system and computer program is developed by using Turbo-C on IBM PC/AT compatible system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.81-86
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• 2020

A ceramic vacuum chamber feedthrough ceramic insulator is made of Al2O3; the manufacturing process involves filling alumina powder into a urethane mold and pressing it with a rubber press to produce a molded body. Thereafter, manufacturing is completed through primary shape processing, sintering, and secondary shape processing in the green body, which is a pressurized molding body, This work is intended to prevent defects in the first shape processing by improving the ceramic insulator in the green body, and to improve the productivity of the ceramic insulator by determining the optimal processing conditions.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.1
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• pp.100-107
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• 2020

As demand for high value-added products with hard materials increases, the line center is used for producing high value-added products in many industries such as aerospace, automobile fields. The line center is a key device for smart factory automation that can improve the production efficiency and the productivity. Therefore, the development of a mill-turn line center is necessary to produce high value-added products with complex shapes flexibly. In the mill-turn process, a milling process and a turning process are combined. In particular, the turning process needs to increase the rigidity of the spindle. The purpose of this study is to analyze the thermal-structural stability through thermo-structural coupled analysis for a mill-turn spindle with a curvic coupling. The maximum temperature and thermal stability of the spindle were analyzed by thermal distribution. In addition, the thermal deformation and thermal-structural stability of the spindle were analyzed through thermo-structural coupled analysis.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.19-27
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• 1994

A laser-based in-process measurement system for the evaluation of surface roughness In turning Is reported. The proposed measuring system makes it possible to detect the surface roughness not only circumferential path but also along the feed direction even during machining. Also, it permits the real-time measurement of surface roughness In dynamic condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.15-19
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• 1994

The application of neural network for fault dection of cutting force in turning was introduced. This monitoring system consist of a RBF predicton model and a ART-1 pattern classifier. RBF prediction model predict a cutting force signal. Prediction error of predictor is used for a input vector of ART-1 pattern classifier. Prediction error could be successfully performed to fault signal monitoring of ART-1 pattern classifier.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.96-97
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• 2001

A 110 mm diameter aspheric metal secondary mirror for a test model of an earth observation satellite camera was fabricated by ultra-precision single point diamond turning (SPDT) . Without a conventional polishing process, the surface texture of R$\sub$a/=2.8 nm, and the form error of R$\sub$a/=0.05 λ has been stably achieved In a laboratory condition. (omitted)

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.118-124
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• 2012

In this study, we turning mold steel (SKD61) using whisker reinforced ceramic tool (WA1) to get affected factor to surface roughness and regression equation. For this study, we adapt system of experiments. Results are follows; From the analysis of variance, it was found that affected factor to surface roughness was feed rate, cutting speed, depth of cut in order. From multi-regression analysis, we calculated regression equation and the coefficient of determination($R^2$). $R^2$ was 0.978 and It means regression equation is significant. Regression equation means if feed rate increase 0.039mm/rev, surface roughness will increase $0.8391{\mu}m$, if cutting speed increase 50m/min, surface roughness will decrease $0.034{\mu}m$, if depth of cut increase 0.1mm, surface roughness will increase $0.0203{\mu}m$. From the experimental verification, it was confirmed that surface roughness was predictable by system of experiments.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.12
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• pp.1353-1358
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• 2011

LAT(Laser Assisted Turning) is a method that applies a machining process after softening a workpiece in which a preheating process is locally applied to its machining section using laser heat source. LAT shows several advantages, such as high productivity, reduction of manufacturing cost, high quality. Analysis of temperature distribution after preheating for LAT is very difficult due to its very small heat input area and large energy and its movement. Also, the LAT for a square bar is more difficult because the shape of a laser heat source can be changed according to the rotation of the workpiece. In this study, thermal analysis for LAT of square bar was performed using laser heat source projection method. And, the analysis results were compared with the results of the prior study of numerical calculation method. It is thus shown that the proposed method is efficient for the thermal analysis of a shaped bar.

• Food Science and Preservation
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• v.20 no.2
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• pp.151-157
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• 2013

This study was conducted to investigate the effect of mature stages on quality of Rafito tomatoes (Lycopersicon esculentum Mill.) during storage at low temperature. Tomatoes grown in greenhouse were harvested at three different mature stages (turning, pink, and red), packaged with a 30-${\mu}m$-thick polyethylene film, and then stored at 5 and $10^{\circ}C$, respectively. The changes in firmness, soluble solids content (SSC), titratable acidity (TA), colour, lycopene content, decay, and chilling injury were measured on a weekly basis. After three weeks of storage, chilling injury and decay were found to have individually occurred at 5 and $10^{\circ}C$, respectively. As there was little change in quality at $5^{\circ}C$, it was concluded that red tomatoes could maintain their good quality for two weeks. The normal postharvest ripening was inhibited in the turning and pink tomatoes during storage at $5^{\circ}C$. The turning and pink tomatoes showed improved quality after two-week storage at $10^{\circ}C$. In particular, the turning fruits showed the highest firmness throughout the storage period. Furthermore, the red colour, SSC/TA, and lycopene content of the turning fruits reached the same levels as with the red fruits after two-week storage at $10^{\circ}C$. These results suggest that red tomatoes should be stored at $5^{\circ}C$ to inhibit decay, and that the optimum temperature for early-harvested tomato (turning and pink) is $10^{\circ}C$ for the ripening process after harvest.