• Journal of the Institute of Convergence Signal Processing
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• v.16 no.3
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• pp.90-95
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• 2015

This study presents a method to test quite small-sized and light-weighted micro-drill bits which are used to make holes in printed circuit boards(PCB). After getting images of micro-drill bits through the high resolution microscope, we developed image processing algorithms to detect fiducial points, and then measured diverse factors of the drill-bit based on these points. We also developed the window-based inspection system to automatically discriminate normal and abnormal status. For the relative comparison of its performance, the system was compared with an existing inspection system using test images. Experimental results showed that the proposed system slightly improved performance, and also classified correctly some misjudged errors which were occurred in the existing system.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.8-13
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• 2016

The micro drill bit automatic regrinding in-line system is a system that refurbishes drill bits used in a PCB manufacturing process. This system is able to refurbish drill bits with a minimum size of ø0.15-0.075mm that have previously been discarded. Beyond the conventional manual cleaning process using ultrasound, this system adopts a water jet cleaning system, making it capable of cleaning drill bits with a minimum size of ø0.15-0.075mm. This paper analyses various contact pressures applied to the surface of drill bits depending on the shooting pressure of the cleaning device and fluid velocity in order to optimize the nozzle location and to detect structural instability caused by the contact pressures.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.489-490
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• 2013

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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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.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.4
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• pp.47-56
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• 2015

In this paper, the Thermal behavior and reliability characteristics of carbon CCL (Copper Claded Layer), which can be used as the core of HDI (High Density Interconnection) PCB (Printed Circuit Board) are evaluated through experiments and numerical analysis using CAE (Computer Aided Engineering) software. For the characterization of the carbon CCL, it is compared with the conventional FR-4 core and Heavy Cu core. From research results, the deformation amount of the flexure strength of PCB is the highest with pitch grade carbon and thermal behavior of PCB is lowest as temperature increases. In addition, TC (Thermal Cycling), LLTS (Liquid-to-Liquid Thermal Shock) and Humidity tests have been applied in the PCB with carbon core and the reliability of PCB with carbon core is confirmed through reliability tests. Also, possibility of uneven surface of the via hole and wear of the drill bit due to the carbon fibers are analyzed. surface of the via hole is uniform, the surface of the drill bit is smooth. Therefore, it is proved that the carbon CCL has the drilling workability of the same level as conventional core material.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.291-297
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• 2015

A water jet cleaning robot system for micro drill bits is to refurbish micro drill bits used for the PCB manufacturing process. It can refurbish drill bits with the minimum diameter of ${\phi}0.15{\sim}0.075mm$ of which the total quantity have been discarded before. Micro drill bits with the minimum diameter of ${\phi}0.075mm$ can be cleaned by applying the water jet cleaning robot system out of the manual ultrasonic cleaning in the past for the cleaning equipment as the initial process in refurbishing. This study analyzed problems, while applying the apparatus mechanism for the workability such as the robot traces of Transfer Robot I and II, drill bit loading and unloading, and cleaning tasks in the water jet cleaning robot system in an effort to carry out simulations. In addition, the cleaning work process was optimized as the work process was verified in advance and the production quantity was analyzed through simulations.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.919-920
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• 2008

In this paper, we present early processing techniques for visual inspection of metallic parts. Since metallic surfaces give rise to specular reflections, it is difficult to extract object boundaries using elementary segmentation techniques such as edge detection or binary thresholding. In this paper, we present two techniques for finding object boundaries on micro bit images. First, we explain a technique for detecting blade boundaries using a directional correlation mask. Second, a line and angle extraction technique based on Harris corner detector and Hough transform is described. These techniques have been effective for detecting blade boundaries, and a number of experimental results are presented using real images.