• Clean Technology
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• v.12 no.3
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• pp.182-189
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• 2006

In this study, high speed machining is evaluated with regard to economical and environmental effects. Considering environmental loads, machining costs are analyzed with the mathematical models of machining economics and cutting fluid loss. Data from the tool life experiments of high speed milling and turning are used for the analysis. The analysis of high speed milling shows that the machining cost decreases as increasing the cutting speed. In turning process, the cooling method using cutting fluid shows the minimum machining cost. Considering both machining and environmental costs, cooling method using cold air is superior to other methods.

• Journal of Korean Institute of Industrial Engineers
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• v.18 no.1
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• pp.155-167
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• 1992

This paper presents an automatic setup planning system for turning operation of symmetric rotational parts. The proposed setup planning system determines workpiece holding method, number of setup, clamping surface, and workpiece holding device by using design data, part description database and part feature recognition information. The workpiece holding method is based on functional name and length/diameter ratio of the given part, and number of setup is determined by part profile type and its technological constraints. Clamping surface and workpiece holding device are determined by using information about the results of workpiece holding method and number of setup, and capacity of workpiece holding devices. A case study is performed to show the performance of the proposed system.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.65.1-65.1
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• 2016

일반적으로 천체 망원경에 사용되는 반사경은 유리 소재로 제작된다. 그러나 알루미늄을 반사경 소재로 사용하면 광기계구조물과 반사경의 열팽창계수가 유사하여 치수 안정성이 높다는 장점이 있다. 뿐만 아니라 다이아몬드 선삭 기계 (Diamond Turning Machine, DTM)를 이용할 수 있기 때문에 반사경의 가공 시간 및 제작 비용을 절감할 수 있다. 본 연구에서는 알루미늄 합금 (Al6061-T6)을 소재로 구경 150 mm, 초점거리 600 mm인 포물면 반사경을 제작하였다. 우선 DTM을 이용해 알루미늄을 가공하였는데, 이 때 표면 조도와 관련된 고주파 오차 (High Frequency Error, HFE)가 발생한다. 따라서 표면 조도를 향상시키기 위한 추가적인 공정으로써 가공된 표면을 도금한 후 열처리를 하고, 폴리싱과 이중 코팅을 거쳐서 최종 반사경을 얻었다. 각 단계별 공정을 마친 후에는 접촉식 및 광학식 형상 측정 방법으로 표면 측정을 실시하여 이를 분석하였다. 본 발표에서는 각 공정 단계에서의 반사경 표면 분석 결과를 설명할 것이며, 제작된 알루미늄 반사경과 기존의 유리 소재의 반사경을 성능 면에서 비교할 것이다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.462-467
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• 2005

This paper presents virtual machining system in order to realize turning process in virtual space. A reliable virtual turning process simulation was developed based on the surface shaping system which is capable of considering geometric model, thermal error model, and vibration model. Accuracy of surface shape resulting from proposed machining simulator was verified experimentally. This paper also developed the watchdog agent that continuously assessed, diagnosed, and predicted performance of products and machines in machining. The Watchdog agent extracted feature signal using time-frequency analysis among various signals from multi-sensor and evaluated machining condition using performance confidence value.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1063-1066
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• 2002

The wavelet transform is a popular tool for studying intermittent and localized phenomena in signals. In this study the wavelet transform of cutting force signals was conducted for the detection of a tool failure in turning process. We used the Daubechies wavelet analyzing function to detect a sudden change in cutting signal level. A preliminary stepped workpiece which had intentionally a hard condition was cut by the inserted cermet tool and a tool dynamometer obtained cutting force signals. From the results of the wavelet transform, the obtained signals were divided into approximation terms and detailed terms. At tool failure, the approximation signals were suddenly increased and the detailed signals were extremely oscillated just before tool failure.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.54-60
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• 2000

Research about tool condition monitoring has been done until now for product automation and unmaned system. But it is hard to apply it to the industrial field due to its cost and reliability. This paper presents the new method of tool wear measurement using Marpos gauge. This is a kind of touch sensor, so its cost is lower than vision system. And it is not affected by dust and illumination, which are important in vision system. This proposed method use tool clearance angle to measure flank wear. Experimental results compared with vision system shows that this method is available for tool condition monitoring system.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.12
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• pp.94-100
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• 2000

This paper presents a methodology for In-Process monitoring of tool wear by using ultrasonic sensor in turning operation. An integrated single ultrasonic transducer operation at a frequency of 10MHz is placed in contact with the insert tip. The change in amount of the reflected energy from the nose and flank of the tool can be related to the level of tool wear and the mechanical integrity of the tool. As the results, the tool wear monitoring system based on the ultrasonic pulse-echo method was proposed, it is useful to determine a tool life and tool change time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.269-273
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• 1997

In order to maker unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for chatter, tool wear and fracture during turning operation. To develop economic sensing and identification methods for turning processes, sound pressure measurement and digital signal processing technique were proposed. We suppressed chatter by stability control methodology, which was studied through manipulation of spindle speeds regarding to chatter frequencies. It was shown that tool wear and fracture were identified and to be estimated by using the wear indices. The validity of the proposed system was confirmed through the large number of cutting tests.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.78-85
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• 2002

The wavelet transform is a popular tool fer studying intermittent and localized phenomena in signals. In this study the wavelet transform of cutting force signals was conducted for the detection of a tool failure in turning process. We used the Daubechies wavelet analyzing function to detect a sudden change in cutting signal level. A preliminary stepped workpiece which had intentionally a hard condition was cut by the inserted cermet tool and a tool dynamometer obtained cutting force signals. From the results of the wavelet transform, the obtained signals were divided into approximation terms and detailed terms. At tool failure, the approximation signals were suddenly increased and the detailed signals were extremely oscillated just before tool failure.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.3
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• pp.53-60
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• 1992

This paper deals with developing an Expert system for tool selection using knowledge base system approach, and its application. For the sake of building of knowledge base, the information from process through sensor, tool handbook and interview with expert are referrenced and managed. The system developed shows good application flexibility in providing the actual cutting process with the selection of tool(insert, holder) and cutting conditions(feed, speed, rake type, and so on), is found as a useful system for real-time machining process. The Expert system for tool selection is written in TURBO PROLOG ver. 2.0 for inference engine capability, and can be run in interactive mode for user friendliness. In order to apply the system developed in actual cutting process, more parameters should be considered and scrutinized, and the system should be further extended in modular basis.