• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.129-132
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• 1996

There is a tendency nowadays to produce increasingly miniaturized electronic equipment which incorporate parts that have to be precisely positioned, like lenses, heads and CCD's in scanners, printers, copiers, VCR's, optical fiber modules, etc. In contrast to the production process of precision parts, which is currently being carried out automatically, the assemblage process is still being performed by specially skilled technicians. The assemblage process comprises normally the following steps: firstly, the parts are roughly positioned and partially fixed, secondly, the parts are manually nudged towards the target position and finally glued, screwed or welded. This paper presents a system that uses six piezo Impact Drive Mechanisms for accurate micro positioning within three degrees of freedom (lateral and longitudinal translation and rotation). The system is designed to positioning a printed circuit board with an accuracy better than 3 .mu.m (for translations), 5 mrad (for rotation).

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.199-207
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• 2002

A virtual laboratory for measurement and instrumentation must aim to realize an integrated environment. To achieve this goal, we designed and implemented a client/server distributed environment and developed a web-based virtual laboratory system for electronic circuits. Since our virtual laboratory system is implemented to describe the on-campus laboratory, the learners can obtain similar experimental data through it. The proposed virtual laboratory system is composed of four important components Principle Classroom, Virtual Experiment Classroom, Evaluation Classroom and Overall Management System. Through our virtual laboratory, the learners will be capable of teaming the concepts and theories related to electronic circuit experiments and how to operate the experimental equipments such as multimeters, function generators, digital oscilloscopes and DC power supplies. Also, every activity occurred in our virtual laboratory is recorded on database and Printed out on the preliminary report form. All of these can be achieved by the aid of the Management System. The database connectivity is made by PHP and the virtual laboratory environment is set up slightly differently for each learner. Finally, we have obtained several affirmative effects such as reducing the total experimental hours and the damage rate for experimental equipments and increasing Loaming efficiencies as well as faculty productivity.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.80-87
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• 2008

Many researches related to the reliability of Pb-free solder joints with PCB (printed circuit board) surface finish under thermal or vibration stresses are in progress, because the electronics is operating in hash environment. Therefore, it is necessary to assess Pb-free solder joints life with PCB surface finish under thermal and mechanical stresses. We have investigated 4-points bending fatigue lifetime of Pb-free solder joints with OSP (organic solderability preservative) and ENIG (electroless nickel and immersion gold) surface finish. To predict the bending fatigue life of Sn-3.0Ag-0.5Cu solder joints, we use the test coupons mounted 192 BGA (ball grid array) package to be added the thermal stress by conducting thermal shock test, 500, 1,000, 1,500 and 2,000 cycles, respectively. An 4-point bending test is performed in force controlling mode. It is considered that as a failure when the resistance of daisy-chain circuit of test coupons reaches more than $1,000{\Omega}$. Finally, we obtained the solder joints fatigue life with OSP and ENIG surface finish using by Weibull probability distribution.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1077-1083
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• 2014

Multi-material Additive Manufacturing (AM) is being focused to apply for direct manufacturing of a product. In this paper, a three-dimensional circuit device (3DCD) fabrication technology based on the multi-material AM technology was proposed. In contrast with conventional two-dimensional Printed Circuit Board (PCB), circuit elements and conducting wires of 3DCD are placed in threedimensional configuration at multiple layers of the structure. Therefore, 3DCD technology can improve design freedom of an electronic product. In this paper, 3DCD technology is proposed based on AM technology. Two types of 3DCD fabrication systems were developed based on the Stereolithography and the Fused Deposition Modeling technologies. And the 3DCD samples which have same function were fabricated, successfully.

• Journal of Advanced Navigation Technology
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• v.17 no.2
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• pp.177-182
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• 2013

In this paper, printed antenna which can be applied to a built-in wireless module of the security controller operating at global positioning system(GPS) L1 frequency band(1.575GHz) is proposed. The proposed antenna is basically composed of a microstrip patch antenna with inserting feed. In particular left and right slots which are respectively asymmetric are used for impedance matching, whereas slot with one open-end and shorting point are used on the bottom plane to set operating frequency and enhance bandwidth. It is observed at the desired GPS L1 frequency band that the radiation efficiency and gain of the proposed antenna are 90% and more than 4.8dBi respectively.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.120-128
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• 2004

The impulse between launch vehicle and atmosphere can generate a lot of noise and vibration during the process of launching a satellite. Structurally, the electronic equipment of a satellite consists of an aluminum case containing PCB. Each PCB has resistors and IC. Noise and vibration of the wide frequency band are transferred to the inside of fairing, subsequently creating vibration of the electronic equipment of the satellite. In this situation, random vibration can cause malfunctioning of the electronic equipment of the device. Furthermore, when the frequency of random vibration meets with natural frequency of PCB, fatigue fracture may occur in the part of solder joint. The launching environment, thus, needs to be carefully considered when designing the electronic equipment of a satellite. In general, the safety of the electronic equipment is supposed to be related to the natural frequency, shapes of mode and dynamic deflection of PCB in the electronic equipment. Structural vibration analysis of PCB and its electronic components can be performed using either FEM or vibration test. In this study, the natural frequency and dynamic deflection of PCB are measured by FEM, and the safety of the electronic components of PCB is evaluated according to the results. This study presents a unique method for finite element modeling and analysis of PCB and its electronic components. The results of FEA are verified by vibration test. The method proposed herein may be applicable to various designs ranging from the electronic equipments of a satellite to home electronics.

• IE interfaces
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• v.7 no.1
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• pp.67-74
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• 1994

In this study, we propose an integrated CAD(Computer Aided Design) library database in a heterogeneous commercial ECAD(Electronic CAD) environment. To effectively solve engineering problems focused on BOM data extraction we use a software system called schematic capture and company-wide standard electronic part information loaded on different commercial ECADs. We unify many commercial ECADs into one schematic capture and a variety of PCB(Printed Circuit Board) design tools. For this purpose we develope a model for linking CAD symbol library with company-wide standard part information. We also develope a schematic design data conversion scheme and show how to extract PBA level BOM data using our customized schematic capture. This system is being operated in an X-Window based engineering work station and commercial RDBMS base.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.324-327
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• 2002

For the characterization of arbitrary shaped printed circuit board, lossy transmission line grid model based on SPICE netlist and analytical plane model based on the segmentation method are proposed in this paper. Two methods are compared with an arbitrary shaped power/ground plane. Furthermore, design considerations for the complete power distribution network structure are discussed to ensure the maximum value of the PDN impedance is low enough across the desired frequency range and to guide decoupling capacitor selection.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.91-95
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• 2005

A heat dissipation modeling method of EEE parts is developed for thermal design and analysis of an satellite electronic equipment. The power consumption measurement value of each functional breadboard is used for the heat dissipation modeling method. For the purpose of conduction heat transfer modeling of EEE parts, surface heat model using very thin ignorable thermal plates is developed instead of conventional lumped capacity nodes. The thermal plates are projected to the printed circuit board and can be modeled and modified easily by numerically preprocessing programs according to design changes. These modeling methods are applied to the thermal design and analysis of CTU and verified by thermal cycling and vacuum tests.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.270-273
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• 2004

The initial thermal analysis needs to be fast and efficient to reduce the feedback time for the optimal electronic equipment designing. In this study, a thermal model is developed by using power consumption measurement values of each functional breadboard, that is, semi-empirical power dissipation method. In modeling heat dissipated EEE parts, power dissipation is imposed evenly on the EEE part footprint area which is projected to the printed circuit board, and is called surface heat model. The application of these methods is performed in the development of a command and telemetry unit (CTU) for a geostationary satellite. Finally, the thermal cycling test is performed to verify the applied thermal analysis methods.