• 한국정밀공학회지
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• 제29권5호
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• pp.489-493
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• 2012

Automatic tool changers(ATCs) store tools used in a machining center to its magazine and changes the tools automatically. Tools of machine centers are changed and then precisely equipped to spindle system by the ATC. Therefore, the stability and reliability of the ATC is very important. But, there is lack of development and evaluation on basic performance and vibration of the ATCs. So, in this study, a BT40 ATC test bench was developed to verify stability and reliability of BT40 ATCs.

• 산업경영시스템학회지
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• 제26권2호
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• pp.68-74
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• 2003

Modem automated manufacturing processes employ automated guided vehicles(AGVs) for material handling, which serve several machining centers(MCs) in a factory. Optimal scheduling of AGVs can significantly help to increase the efficiency of the manufacturing process by minimizing the idle time of MCs waiting for the raw materials. In this paper, we will analyse the requirements for an optimal schedule and then provide a mathematical framework for an efficient schedule of material delivery by an AGV. With this model, the optimal number of MCs to be utilized will also be determined. Finally, the material delivery schedule employing multiple journeys to the MCs by the AGV will be carried out. Through rigorous analysis and simulation experiments, we shall show that such a delivery strategy will optimize the overall performance.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.361-364
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• 2001

CNC technology is used in various industrial fields, whose best example is the product part. The technology has been applied to machine tools such as automatic lathes and machining centers, etc. Recently, CNC technology has been applied not only to industrial parts but also to consumer part such as dental prosthesis and 3D face carving machine. In this paper, we introduce the application of the CNC technology to the 3D face carving machine, which the public has been not familiar with yet. It enables general users to control the machine and get the product with ease. We also mention examples of the application of the technology to the related fields and the way open CNC technology is used in controlling the calving machine.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.342-346
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• 1997

In the recent competitive market situation, the product development lead-time plays a significant role for the success of a manufacting company. One of the most important efforts required is reducing the design lead-time by managing all the necessary technical information related to the design process. In this paper,the data model for an engineering data management system for machine tools is described by applying object-oriented modeling technique. The design objects and their structure are defined regarding the functions such as version control, configuration management, and technical document management, and are implemented using an object-relational database management system. The suggested model takes into special account the characteristics of machining centers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.1250-1255
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• 1990

This paper discusses an optimal cyclic scheduling problem for a FMC (Flexible Manufacturing Cell) modeled by a two-machine flowshop with two machining centers with APC's (Automated Pallet Changers), an AGV (Automated Guided Vehicle) and loading and unloading stations. Cyclic production in which similar patterns of production is repeated can significantly reduce the production lead-time and WIP (Work-In-Process) in such flexible, automated system. Thus we want to find an optimal cyclic schedule that minimizes the cycle time in each cycle. However, the existence of APC's as buffer storage for WIP makes the problem intractable (i.e., NP-complete). We propose an practical approximation algorithm that minimizes, instead of each cycle time, its upper bound. Performances of this algorithm are validated by the way of computer simulations.

• 한국산학기술학회논문지
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• 제20권8호
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• pp.164-173
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• 2019

본 연구에서는 전 세계 3대 에어쇼 중의 하나인 "FIA(Farnborough International Airshow, 판보로 국제 에어쇼)"의 참여기관/업체를 대상으로 네트워크 분석을 활용하여 항공우주분야 기술동향을 분석하였다. 판보로 국제 에어쇼는 전 세계 주요 항공관련 민간 및 방산 업체와 각국 정부 및 군 관계자가 참여하여 항공우주산업분야에 대한 최신 기술을 선보이는 중요한 행사로서, 2018 FIA에서는 총 112개 국가에서 1,500여 업체(기관)가 참여하였다. 본 연구에서는, 항공우주분야 기술관련 45개 국가, 1,108개 업체를 대상으로 223개의 기술 분류 카테고리를 통해 네트워크 분석 중 하나인 키워드 기반의 중심성 분석을 수행하였다. 분석결과, 전 세계적 우주항공 분야의 핵심기술은 "Machining"으로 조사되었다. 하지만 지역(국가) 별로 분류되는 핵심기술은 다소 다른 경향을 보여주고 있었는데, 유럽(EU)과 영국의 경우 "Machining", 아시아의 경우 "Aircraft Components", 미국의 경우 "Engine Components/controls"가 식별되었다. 우리나라의 경우에는 관련 기관/업체 수의 부족으로 뚜렷한 중심 기술이 식별되지 않았다. 본 연구의 결과가 우주항공분야 기술기획 및 연구 방향성 제시를 위한 참고자료로서 활용 될 수 있으며, 또한 국내 관련 업체의 수출 진흥을 위한 국외 주요 기술 분야를 제시하는데 유용하게 활용되리라 기대한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.537-540
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• 1992

This paper presents Samsung CNC (Computer Numerical Controller) system with an intel 80486/487 as the main CPU and a 32 bit floating point DSP(Digital Signal Processor) TMS320C30 as the motion control CPU. The Samsung CNC system diverse user-frienly characteristics such as multi-tasking, powerful menu system, internal PLC system, and 2/3 dimensional graphics in wire and solid mode. The main CPU executes central processing program, user interface program, interpreter, BMI, etc while the motion control CPU carries out some interpolations, acceleration/deceleration, and PID control algorithm with feedforward terms. Complex interpolations except linear and circular ones are performed on the main control CPU. The experimental results for the circular interpolation under linear acceleration/deceleration shows that the proposed CNC system can be widely used in controlling machining centers with good machining accuracy.

• 한국정밀공학회지
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• 제30권4호
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• pp.397-402
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• 2013

In this study, we carried out the each lines of section, using GC (green silicon carbide) whetstone, the SCM415 material which separated by after and before heat treatments process, in 3+2 axis machining centers for integrated grinding after cutting end mill works, the spindle speed 8000 rpm and feed rate 150 mm/min. For the analysis of the centerline average roughness (Ra), we measured by 10 steps stages. Using Finite element analysis, we found the result of the load analysis effect of the assembly parts, when applied the 11 kg's load on both side of the ATC (Automatic tool change) arm. The result is as follows. For the centerline average roughness (Ra) in the non-heat treatment work pieces, are appeared the most favorable in the tenth section are $0.510{\mu}m$, that were shown in the near the straight line section which is the smallest deformation of curve. In addition, the bad surface roughness appears on the path is to long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.

• 한국산업보건학회지
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• 제15권3호
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• pp.166-175
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• 2005

Health effects associated with metal working fluid (MWF) exposures include dermatitis, respiratory disease, hypersensitive pneumonitis, and asthma. Frequently, occupational exposures to MWFs are controlled by ventilating an enclosure with an air cleaning unit that includes a fan preceded by various kinds of filtration. There are several kinds of air cleaning units used in machining centers. But the associated troubles have hindered from efficiently using these devices. The main problem is the relatively short period of filter replacement. The reason is that the air cleaning units usually do not have the de-oiling systems, thus leading the earlier clogging of filters and reducing the flow rate of hood. Thus, the first stage of study was conducted to overcome this problem by developing the new oil mist collector equipped with the easy de-oiling system. The principle of de-oiling is that the centrifugal force generated by spinning the drum covered by filter fabric separates oils from the filter fabric. It would be very similar to the spin-dry laundry. By adopting this de-oiling technique, the problems associated with the conventional oil mist collectors could be solved. Several tests/analyses were performed to make the lab-scale oil mist collector. The collection efficiencies and the de-oiling efficiencies of commercially available filter fabrics were tested. Subsequently, the endurance test were conducted by observing SEM photos of filter fabrics and measuring tensile strength/expansion coefficient after spinning the filter drum for 20 minutes at the different rotation speeds. By doing these experiments, the most appropriate filter fabric and rotation speed/duration were selected. Finally, the new oil mist collector was designed. In the near future, this device must be tested in the real machining center.

• 대한기계학회논문집A
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• 제35권6호
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• pp.661-667
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• 2011

접촉식 측정 프로브는 3 차원 좌표 측정기 및 CNC 공작기계 등에서 제품 검사에 많이 활용되고 있고, 최근 품질 향상을 위한 가공 및 검사장비의 고정도화에 따라 측정의 정확도도 또한 매우 중요시 되고 있다. 이에 따라 스트레인 게이지 등을 이용한 고정도의 측정 프로브가 사용되고 있기는 하지만, 본 연구에서는 경제적인 측면을 고려하여 산업현장에서 공작기계에 많이 활용되는 일반 접촉식 측정 프로브의 메커니즘을 이해하고, 측정 시 발생할 수 있는 프로빙 오차에 대한 분석 및 보정을 통하여 그 활용성을 높이고자 하였다. 이를 위하여 스타일러스 반경 및 중심 정렬오차가 규명되었고, 3 차원 공간상의 측정 좌표에서 프로빙 오차에 대한 해석이 이루어졌다. 이러한 오차들을 보정하기 위한 알고리즘이 개발되었으며, 실제 CNC 공작기계 상에서 기준구 측정을 통한 검증이 이루어졌다.