• 한국정밀공학회지
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• 제22권3호
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• pp.15-20
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• 2005

This paper describes the PCB drilling using an ultra high-speed air bearing spindle system and micro drill. For this research, we have developed the ultra high-speed air bearing spindle of 125,000 rpm and made an experiment for the application possibility in the PCB drilling. In order to estimate the drilling performance, we have investigated the size and damage of drilled hole, and the wear of drill at 90,000rpm. Results are as follows; we have confirmed the possibility in the PCB drilling of air bearing spindle. In case of micro-drilling PCB at $0.1mm\sim0.3mm$, the increase in the number of drilling has resulted in a bigger size of holes and also a bigger size of damage. It has been found that the wear of micro drill tends to concentrate in the main cutting edge.

• 한국기계가공학회지
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• 제21권3호
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• pp.77-85
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• 2022

In this study, to diagnose the grinding state of a micro drill bit, a sensor attachment location was selected through random vibration analysis of the grinding unit of the micro drill-bit grinding system. In addition, the vibration data generated during the drill bit grinding were collected from the grinding unit for the grinding wheels under the steady and worn conditions, and data feature extraction and dimension reduction were performed. The wear of the micro-drill-bit grinding wheel was diagnosed by applying KNN, a machine-learning algorithm. The classification model showed excellent performance, with an accuracy of 99.2%. The precision, recall and f1-score were higher than 99% in both the steady and wear conditions.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.926-931
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• 2002

Although ceramic plates with many micro-hales are used as MCP (Micro-channel plate) for electron amplification, catalytic converters, filters, electrical insulators and thermal conductors in integrated circuits, the drilling of micro-hales in the ceramics is difficult because of their low thermal conductivity, high hardness and brittleness. Therefore, in this work, the machining of ceramic green body fellowed by sintering of green body was employed fur fabricating ceramic plates with many micro-holes. The micro-drilling of alumina green body was performed with diamond abrasive WC drills, and the cutting force w.r.t. drilling times was measured for the determination of toot life. From the investigation of the wear of micro-drill tip w.r.t. drilling times, the wear mechanism of tip during micro-drilling of ceramic green body was suggested.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.47-56
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• 2015

본 논문에서는 HDI(High Density Interconnection) 기판의 코어로 사용될 수 있는 카본 CCL(Copper Claded Layer)의 열거동 및 신뢰성 특성을 실험과 CAE를 이용한 수치해석을 통해 평가하였다. 카본 CCL의 특성평가를 위해 기존 FR-4 코어와 heavy cu 코어와 비교하였다. 연구결과에 의하면 pitch계열 카본코어가 적용된 PCB의 휨강도가 가장 높고 온도에 따른 변형량이 가장 낮았다. 또한, HDI 신뢰성평가 기준의 TC(Thermal Cycling), LLTS(Liquid-to-Liquid Thermal Shock), Humidity 실험을 통해 카본코어가 적용된 PCB는 신뢰성이 확보되었음을 확인하였다. 카본 파이버에 의한 불균일한 비아홀의 표면형상 여부와 드릴비트 마모 가능성을 분석하였는데 비아홀의 표면은 균일하고, 드릴비트의 표면도 매끄러워 카본 CCL의 우수한 드릴가공성도 확인하였다.

• 마이크로전자및패키징학회지
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• 제22권4호
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• pp.37-46
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• 2015

본 논문에서는 PCB용 카본 CCL의 열전달 특성을 실험과 수치해석을 통해 연구하였는데 카본 CCL의 특성 연구를 위해 기존 FR-4 코어와 Heavy copper 코어를 적용한 PCB를 비교하였다. 열전달특성 분석을 위해 코어는 한 개와 두 개가 적용된 HDI PCB 샘플이 제작되었고, 카본코어는 Pan grade와 pitch grade의 2종이 적용되었으며, 코어 두께에 의한 열전달 특성도 평가되었다. 연구결과에 의하면 카본 코어의 열전달 특성은 heavy copper 코어보다는 낮으나 FR-4 코어보다는 우수하였다. 또한, 카본 코어와 heavy copper 코어는 두께가 증가할수록 열전달 특성이 높아졌으나 FR-4 코어는 두께가 증가할수록 열전달 특성이 낮아졌다. heavy copper 코어 적용시 드릴마모도 증가, 무게 증가, 전기절연성 확보를 위한 절연재의 추가로 원가상승을 고려할 때 카본 코어가 PCB의 열전달 특성 향상을 위한 대안이 될 것으로 판단된다.