• Transactions on Electrical and Electronic Materials
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• v.13 no.3
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• pp.129-135
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• 2012

A number of surface mount technology (SMT) process variables including land design are considered for minimizing tombstone defect in flexible printed circuit assembly in high volume manufacturing. As SMT chip components have been reduced over the past years with their weights in milligrams, the torque that once helped self-centering of chips, gears to tombstone defects. In this paper, we have investigated the correlation of the assembly process variables with respect to the tombstone defect by employing statistically designed experiment. After the statistical analysis is performed, we have setup hypotheses for the root causes of tombstone defect and derived main effects and interactions of the process parameters affecting the hypothesis. Based on the designed experiments, statistical analysis was performed to investigate significant process variable for the purpose of process control in flexible printed circuit manufacturing area. Finally, we provide beneficial suggestions for find-pitch PCB design, screen printing process, chip-mounting process, and reflow process to minimize the tombstone defects.

• Fire Science and Engineering
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• v.33 no.2
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• pp.56-62
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• 2019

A sprinkler is a fire extinguishing equipment installed in a protected area where a detector or head detects a fire and automatically puts out the fire. However, the Ministry of Land, Infrastructure and Transport's "Regulations on Building Evacuation and Fire Protection Standards, etc." stipulate that fire compartment area should be reduced to three times by installing sprinkler facilities in the case of factories and warehouses. In this study, fire hazard was analyzed for a real PCB factory which mitigated the fire protection zone by sprinkler installation, and the head opening characteristics of sprinkler facilities through computer simulation, installation standards of sprinkler facilities, thermal performance, operating range, and the amount of water sprayed to identify the problems of operation of sprinkler facilities in case of fire, and to suggest the grounds such as required sprinkling flow rate for system improvement.

• 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 Korean Society of Environmental Engineers
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• v.39 no.9
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• pp.527-533
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• 2017

Environmental concern about smart phone is growing because it has short product life span while having intensive production technology and cost. In this study environmental impact of the smart phone is quantified using the LCA methodology based on the ISO 14040 series standards. The assessment considers potential environmental impacts across the whole life cycle of the smart phone including; pre-manufacturing; manufacturing; distribution; product use; and end-of-life stages. The pre-manufacturing stage is the most dominant life cycle stage causing the highest environmental impacts among all 10 impact categories assessed. The global warming impacts of the smart phone in the pre-manufacturing, distribution, use, manufacturing, and end-of-life stages were 52.6% 23.9%, 15.7%, 7.0%, and 0.8%, respectively. Sensitivity of the life cycle impact assessment results to the system boundary definition and assumptions made were quite high. Three components of the smart phone, PCB, battery, and display module were identified as the key components causing majority of the potential environmental impact in the pre-manufacturing stage. As such the slim and light-weight design and the use of environmental friendly materials are important design factors for reducing the environmental impact of the smart phone.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1193-1196
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• 2007

A new planar transformer type energy recovery circuit for PDP is proposed in this paper. The same current is transferred through both the primary and secondary sides during the energy recovery period. The conduction loss is reduced. Fabrication through simple manufacturing processes is possible using the PCB winding.

• The Optical Journal
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• s.136
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• pp.53-55
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• 2011

국내 최대 규모의 전자제조장비 종합 전시회 (Electronics Manufacturing Korea)가 2012년 4월 11일부터 13일까지 코엑스 전시장에서 개최된다. 이 전시회는 국내 주요 전자산업 핵심 분야별 비즈니스 활성화를 위해 광전자 전시회인 'Photonics Seoul'과 함께 'SMT/PCB & NEPCON KOREA', 'Printed Electronic & Electronics Materials Show', 'LED Packaging EXPO', 'Film Technology Show' 등 5개 전시회가 동시 개최되어 전시기간 동안 한자리에서 국내 최대 전자제조 장비의 최신 기술 및 제품 동향은 물론， 다양한 국내외 바이어를 만날 수 있는 기회가 될 것으로 기대된다.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.29 no.2
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• pp.7-12
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• 2006

This study considers the problem of scheduling jobs on uniform parallel machines with a common due date. The objective is to minimize the total absolute deviation of job completion times about the common due date. This problem is motivated by the fact that a certain phase of printed circuit board manufacturing is bottleneck and the processing speeds of parallel machines in this phase are uniformly different for all jobs. Optimal properties are proved and a simple polynomial time optimal algorithm is developed.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2549-2551
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• 2003

We propose character recognition system for Gerber files. The Gerber file is the vector-formatted drawing file for PCB manufacturing. To consider the special vector format and rotated characters, we develop segmentation and feature extraction method. The modularized neural network is then applied to the recognition algorithm. Finally, comparative simulation results are presented to verify the usefulness of the proposed method.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.17-24
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• 1992

The capacity of the drilling process in Multi-Layer PCB fabrication can be affected by various process parameters determining material flows in the unit operations. The ratio of mass-lamination to pin lamination and the number of stacks as the most critical paramaters, among them, were chosen on the basis of exhaustive field evaluation to study their effects on the capacity of the process. The best alternative condition for maximum capacity of the process was selected by simulation of process.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.73-80
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• 2020

The 3D printing of electronics has been a major application topics in additive manufacturing technology for a decade. In this paper, wireless power transfer (WPT) technology for 3D electronics is studied to supply electric power to its inner circuit. The principle of WPT is that electric power is induced at the recipient antenna coil under an alternating magnetic field. Importantly, the efficiency of WPT does rely on the design of the antenna coil shape. In 3D printed electronics, a flat antenna that can be placed on the printed plane within a layer of a 3D printed part is used, but provided a different antenna response compared to that of a conventional PCB antenna for NFC. This paper investigates the WPT response characteristics of a WPT antenna for 3D printed electronics associated with changes in its design elements. The effects of changing the antenna curvature and the gap between the wires were analyzed through experimental tests.