• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.394-401
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• 2003

We consider a PCB grouping problem arising from the electronic industry. Given a surface mounting device, several types of PCBs and a number of component feeders used to assemble the PCBs. the optimization problem is the PCB grouping problem while minimizing setup time of component feeders. We formulate the problem as an Integer programming model and propose a column generation approach to solve the Integer programming formulation. In this approach we decompose the original problem Into master problem and column generation subproblem Starting with a few columns in the master problem. we generate new columns successively by solving subproblem optimally. To solve the subproblem. we use a branrh-and-rut approach. Computational experiments show that our solution approach gives high quality solutions in a reasonable computing time.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1219-1226
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• 2013

This study is the analysis and verification process of the L-band satellite communications repeater thought PCB & circuit EM analysis. System performance can be vulnerable to various spurious inside the L-band satellite transponder, power conversion board, digital signal board, TM/TC board, such as control panels and blocks that are linked signal components when the winch is increased due to the noise component. So the whole system can cause performance degradation. PCB resonance analysis and EM simulation can be easily analyzed for a variety of optimal. Also, by setting the ports on the PCB, H/W designer wants to can easily analyze system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.24 no.66
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• pp.91-98
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• 2001

In this study, a heuristic for surface mounters is developed to find an efficient sequence on PCB and rack assignment by component grouping. As setting up 4 reels in a group, the distance of rack moving can be minimized. And then, a generalized model for N reels in a group is developed. It is found that the performance of this heuristic is better than other heuristics found in the literature. Throughout the simulation study, the suggested heuristic is performed about 8.2 ∼ 12% better than other heuristics.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.187-195
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• 2000

Nucleotide sequence extending 2,3-dihydroxybiphenyl 1,2-dioxygenase gene (pcbC) and 2-hydroxy-6-oxo-6-phenylhexa-2,4-dienoate hydrolase gene (pcbD) of Pseudomonas sp. DJ-12 was previously analyzed and the two genes were present in the order of pcbD-pcbC preceded by a promoter from Pseudomonas sp. DJ-12. In this study, a 3.8-kb nucleotide sequence located downstream of the pcbC gene was analyzed to have three open reading frames (ORFs) that are designated as orf1, pcbE and orf2 genes. All of the ORFs were preceded by each ribosome-binding sequence of 5-GGAXA-3 (X=G or A). However, no promoter-like sequence and transcription terminator sequence were found in the analyzed region, downstream of pcbC gene. Therefore, the gene cluster appeared to be present in the order of pcbD-pcbC-orf1-pcbE-orf2 as an operon, which is unique organization characterized so far in biphenyl- and PCB-degrading bacteria. The orf1 gene was composed of 1,224 base pairs which can encode a polypeptide of molecular weight 44,950 containing 405 amino acid residues. A deduced amino acid sequence of the orf1 gene product exhibited 21-33％ identity with those of indole dioxygenase and phenol hydroxylase components. The pcbE gene was composed of 783 base pairs encoding 2-hydroxypenta-2,4-dienoate hydratase involved in the 4-chlorobiphenyl catabolism. The orf2 gene was composed of 1,017 base pairs encoding a polypeptide of molecular weight 37,378 containing 338 amino acid residues. A deduced amino acid sequence of the orf2 gene product exhibited 31％ identity with that of a nitrilotriacetate monooxygenase component.

• Journal of Korean Institute of Industrial Engineers
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• v.20 no.4
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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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.

• Journal of the Microelectronics and Packaging Society
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• v.30 no.3
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• pp.40-50
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• 2023

Recently, the number of components of smartphones increases rapidly, while the PCB size continuously decreases. Therefore, 3D technology with a stacked PCB has been developed to improve component density in smartphone. For the s tacked PCB, it i s very important to obtain solder bonding quality between PCBs. We investigated the effects of the properties, thickness, and number of layers of interposer PCB and sub PCB on warpage of PCB through experimental and numerical analysis to improve the reliability of the stacked PCB. The warpage of the interposer PCB decreased as the thermal expansion coefficient (CTE) of the prepreg decreased, and decreased as the glass transition temperature (Tg) increased. However, if temperature is 240℃ or higher, the reduction of warpage is not large. As FR-5 was applied, the warpage decreased more compared to FR-4, and the higher the number and thickness of the prepreg, the lower the warpage. For sub PCB, the CTE was more important for warpage than Tg of the prepreg, and increase in prepreg thickness was more effective in reducing the warpage. The shear tests indicated that the dummy pad design increased bonding strength. The tumble tests indicated that crack occurrence rate was greatly reduced with the dummy pad.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.44-44
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• 1993

• Aerospace Engineering and Technology
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• v.4 no.2
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• pp.203-208
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• 2005

Electronic components for space launch vehicles are exposed to a severe vibrational environment at launch and flight. The structural reliability of each component can be verified using mathematical approaches. In order to verify the structural reliability, an important parameter is the natural frequency of PCB(Printed Circuit Board) assembly mounted electronic components on and housing mounted PCB assembly in. In this paper, in order to find natural frequencies of PCB assemblies and the housing of hydrazine TCU(Thruster Control Unit), FEM(Finite Element Method) is adapted. The analytical result of FEM is verified by experimental method.

• The Journal of the Korea Contents Association
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• v.6 no.4
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• pp.46-54
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• 2006

We propose an optimization method for PCB assembly lines including multiple surface mounters. To increase the productivity of PCB assembly line, the component allocation, feeder assignment, and assembly sequence of each surface mounter should be optimized. The optimization Problem is formulated as an integer programming problem. We divide the overall problem into two hierarchical sub-problems: forward-path problem and backward-path problem. The clustering algorithm and branch-and-bound algorithm are applied to solve the forward-path problem. The assignment algorithm and connection algorithm are applied to solve the backward-path problem. Simulation results are presented to verify the usefulness of the proposed method.