• 한국기계가공학회지
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• 제15권6호
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• pp.24-34
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• 2016

To attach a fuel tank to an excavator, two sets of mounting plates on which three bosses are attached are welded onto the tank. In this study, the welding process of a fuel tank for an excavator was modeled using a finite element numerical method. The tank was modeled as a simple plate to which the mounting plate or bosses were attached by fillet welding. Thermal and thermo-elasto-plastic analyses of the welding process were carried out to predict the temperature distribution and material distortion during welding, respectively. Three different welding sequences for the tank were also modelled to compare the deformation that occurred due to each welding sequence. The results of the analysis predicted that changing the welding sequence around the mounting plate could not position the boss within the allowable dimensional range. The results also revealed the sequence in which the maximum distortion of the bosses welded onto the tank was 30% less than the maximum distortion due to the other sequences.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 추계학술대회 논문집
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• pp.276-280
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• 2001

In the development of Chip Mounter(C/M), much interests have risen regarding how to decrease the operation time of mounting the different chips on the printed circuit board(PCB). The existing method to determine the time sequence of teaching C/M was to follow the procedure which was made by the operater. IN this study, a new but effective algorithm has been developed and employed in SCM-130 Chip Mounter and its online programming had reduced the mounting time significantly and provided the basis for the future online CAD/CAM system.

• 산업공학
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• 제10권1호
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• pp.155-167
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• 1997

The purpose of this study is to develop the program for efficient operation of a multi-functional surface mounting device(SMD) which mount various components on a printed circuit board(PCB). These components are provided by diverse types of feeders such as cassette, stick and tray feeders. The SMD has one or two heads. In the SMD, the positions of PCB and feeders and fixed, and the head moves to pick up a component from a feeder and to mount it on the PCB. The number of lanes occupied by each feeder and the nozzle used for each component can be different. We develop an off-line program to minimize the cycle-time of the SMD by studying the optimal assignment of feeders and the optimal mounting sequence of components. Graphical User Interface(GUI) is also developed. Additionally, we consider the line balancing problem which appears when two SMDs are used sequentially.

• 산업경영시스템학회지
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• 제43권4호
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• pp.67-75
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• 2020

This paper proposes a methodology for gantry route optimization in order to maximize the productivity of a odd-type surface mount device (SMD). A odd-type SMD is a machine that uses a gantry to mount electronic components on the placement point of a printed circuit board (PCB). The gantry needs a nozzle to move its electronic components. There is a suitability between the nozzle and the electronic component, and the mounting speed varies depending on the suitability. When it is difficult for the nozzle to adsorb electronic components, nozzle exchange is performed, and nozzle exchange takes a certain amount of time. The gantry route optimization problem is divided into the mounting order on PCB and the allocation of nozzles and electronic components to the gantry. Nozzle and electronic component allocation minimized the time incurred by nozzle exchange and nozzle-to-electronic component compatibility by using an mixed integer programming method. Sequence of mounting points on PCB minimizes travel time by using the branch-and-price method. Experimental data was made by randomly picking the location of the mounting point on a PCB of 800mm in width and 800mm in length. The number of mounting points is divided into 25, 50, 75, and 100, and experiments are conducted according to the number of types of electronic components, number of nozzle types, and suitability between nozzles and electronic components, respectively. Because the experimental data are random, the calculation time is not constant, but it is confirmed that the gantry route is found within a reasonable time.

• 경영과정보연구
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• 제34권2호
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• pp.67-78
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• 2015

본 연구는 작업 순서에 따라 달라지는 준비비용을 갖는 인쇄회로기판의 생산 일정계획 문제를 다룬다. 본 연구에서 다루는 문제는 생산할 인쇄회로기판의 유형들이 주어져있으며, 이는 한 대의 부품장착 설비를 통해 생산되는 환경에서, 작업 투입 순서에 따라 달라지는 준비 비용의 총합을 최소화는 작업 투입순서를 결정하는 것이다. 이 문제는 NP-hard로 알려져 있으며, 이에 해를 도출하기 위한 메타 휴리스틱 기법을 제시한다.

• 한국시뮬레이션학회논문지
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• 제14권2호
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• pp.25-34
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• 2005

Determination of component mounting sequence on printed circuit board assembly process is a typical NP-hard problem. It is a kind of traveling salesman problems, but it has one more hard to meet constraint of matching component type per mounting position as well as searching the shortest path. An efficient method is developed by separation of crowed area and allowing up to two slots per component type. A simulation model is constructed using Visual C++ for evaluation of the suggested heuristic.

• 산업경영시스템학회지
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• 제29권1호
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• pp.63-71
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• 2006

In this paper, we consider a planning problem arising from printed circuit board manufacturing industries. Given a set of several types of PCBs, component feeders and surface mounting machines in series in a PCB assembly line, the problem is to define the feeder allocation and job sequence with the objective of minimizing the total operation time of the line. We formulate the problem as a mathematical model. And, the problem is proven to be NP-hard, so a genetic algorithm is developed. Finally, we give test results to evaluate the performance of the genetic algorithm.

• 한국기계기술학회지
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• 제13권2호
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• pp.1-7
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• 2011

The CFRP composite has a lot of merits such as mechanical characteristic, light and thermal resistance. For these merits, CFRP is applied to so many industrial area. In order to use the composite materials in the aircraft structures or machine elements, accurate surfaces for bearing mounting or joints must be provided, which require precise, machining. In this study, the specimens differentiating the stacking sequence of 5kinds were used. When drilling the carbon fiber reinforced plastics, it was checked on whether the stacking sequence reached any effect on the cutting force. Also relationship between the drill diameter is examined from the drilling experiment, which is the drilling of Fabric, Unidirectional specimen with ∅6mm, ∅10mm, ∅12mm cemented carbide drill. Considering cutting force and drilling diameter, the results are analyzed.

• 대한기계학회논문집B
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• 제37권11호
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• pp.1037-1046
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• 2013

본 연구에서는 측정기준 수립을 위해 실험된 결과를 통계적으로 분석하였다. 측정오차에 미치는 영향력의 크기는 회선 수, 센서의 설치각도 및 직관거리가 심한 영향을 미치며 레이놀즈수가 다음으로 영향을 준다. 2중 곡관하류의 유동패턴을 이해하기 위하여 3D 수치해석을 수행하였다. 수치해석 결과는 1회선에서 센서의 설치각도 $0^{\circ}$와 $45^{\circ}$, $135^{\circ}$의 L/D=3과 5의 경우가 실험과 잘 일치하는 것으로 나타났다. 결과적으로 레이놀즈수 700,000~1,400,000일 때, 1회선 초음파유량계는 센서의 위치를 L/D=3의 $45^{\circ}$에 설치함으로서 오차를 줄일 수 있다.

• 대한산업공학회지
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• 제20권4호
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• pp.23-35
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• 1994

Efficient operation of a component placement machine with a multi-head in a PCB assembly process is considered. The problem consists of two subproblems, which are the optimal allocation of the component tape reels in the rack and the optimal mounting sequence of the components on a printed circuit board. We analyze the problem and propose a heuristic algorithm to solve it. The heuristic can be used for the one head case too. Computational experiences on some real world problems show the effectiveness of the heuristic in terms of speed and solution quality.