The Experts below are selected from a list of 2091 Experts worldwide ranked by ideXlab platform
Yuexian Song - One of the best experts on this subject based on the ideXlab platform.
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wear mechanisms of micro drills during dry high speed drilling of pcb
Journal of Materials Processing Technology, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In this paper, micro-drills with diameters of 0.1–0.3 mm were used to drill printed circuit boards (PCBs) with a highest spindle speed of 300 krpm. To study the wear mechanisms of PCB micro-drills, micro-drill morphology was observed, and the flank wear of the micro-drills was measured. The factors affecting flank wear were studied. In addition, hole wall roughness, Nail Head formation, and the accuracy of hole location were measured and analysed to determine how micro-drill wear influenced hole quality. It was found that abrasion was the main mechanism controlling the deterioration of cemented tungsten carbide micro-drills. The aggressive rubbing by glass fibre broken chips and reinforcing fillers, and the diffusion of cobalt caused abrasive wear of the flank, the chisel edge, the rake face, and the minor flank of the micro-drills. Resin that was softened by cutting heat would adhere to the micro-drills, which decreased chip removal and the accuracy of hole location. Micro-drill wear was inclined to cause Nail Heads and decrease the accuracy of hole location.
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characteristics of chip formation in the micro drilling of multi material sheets
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In order to meet the requirements of electronic product miniaturisation, the use of thinner and smaller printed circuit boards (PCBs) will be required. To achieve this, many more micro-holes must be drilled in a smaller area than before. PCBs are anisotropic multi-material sheets consisting of a dielectric layer (resin/glass fibre cloth) and a high purity metal conductor (copper foil). It is difficult to achieve high machining precision, surface quality, drilling efficiency and long drill life when drilling PCB micro-holes. In this study, micro-drills with a diameter of 0.1 mm were used to drill the PCBs at rotational speeds of up to 300 krpm. The drilling process was digitally photographed. The chip morphology and the hole wall were observed. The quality of the hole wall, such as hole wall roughness and Nail Head and exit burr formation were observed and measured. The influence of drilling condition on the drilling process and hole quality were studied. It was found that the morphology of the chips and the hole wall surface depended on the material properties of the printed circuit board. Chips were formed normally as conical helical chips from the aluminium entry board, conical helical chips from the copper foil and discontinuous chips from the glass fibre and softened resin. The hole wall through the copper foil seemed much smoother than that of resin/glass fibre cloth layer. However, Nail Heads and burrs were formed at the copper foil layers, which decreased the hole quality. Chip morphology and hole quality were affected by feed rate, spindle speed and tool wear. The basic removal mechanism of the PCB micro-holes was analysed, and this study provided a firm foundation for further work in this area.
Lijuan Zheng - One of the best experts on this subject based on the ideXlab platform.
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wear mechanisms of micro drills during dry high speed drilling of pcb
Journal of Materials Processing Technology, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In this paper, micro-drills with diameters of 0.1–0.3 mm were used to drill printed circuit boards (PCBs) with a highest spindle speed of 300 krpm. To study the wear mechanisms of PCB micro-drills, micro-drill morphology was observed, and the flank wear of the micro-drills was measured. The factors affecting flank wear were studied. In addition, hole wall roughness, Nail Head formation, and the accuracy of hole location were measured and analysed to determine how micro-drill wear influenced hole quality. It was found that abrasion was the main mechanism controlling the deterioration of cemented tungsten carbide micro-drills. The aggressive rubbing by glass fibre broken chips and reinforcing fillers, and the diffusion of cobalt caused abrasive wear of the flank, the chisel edge, the rake face, and the minor flank of the micro-drills. Resin that was softened by cutting heat would adhere to the micro-drills, which decreased chip removal and the accuracy of hole location. Micro-drill wear was inclined to cause Nail Heads and decrease the accuracy of hole location.
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characteristics of chip formation in the micro drilling of multi material sheets
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In order to meet the requirements of electronic product miniaturisation, the use of thinner and smaller printed circuit boards (PCBs) will be required. To achieve this, many more micro-holes must be drilled in a smaller area than before. PCBs are anisotropic multi-material sheets consisting of a dielectric layer (resin/glass fibre cloth) and a high purity metal conductor (copper foil). It is difficult to achieve high machining precision, surface quality, drilling efficiency and long drill life when drilling PCB micro-holes. In this study, micro-drills with a diameter of 0.1 mm were used to drill the PCBs at rotational speeds of up to 300 krpm. The drilling process was digitally photographed. The chip morphology and the hole wall were observed. The quality of the hole wall, such as hole wall roughness and Nail Head and exit burr formation were observed and measured. The influence of drilling condition on the drilling process and hole quality were studied. It was found that the morphology of the chips and the hole wall surface depended on the material properties of the printed circuit board. Chips were formed normally as conical helical chips from the aluminium entry board, conical helical chips from the copper foil and discontinuous chips from the glass fibre and softened resin. The hole wall through the copper foil seemed much smoother than that of resin/glass fibre cloth layer. However, Nail Heads and burrs were formed at the copper foil layers, which decreased the hole quality. Chip morphology and hole quality were affected by feed rate, spindle speed and tool wear. The basic removal mechanism of the PCB micro-holes was analysed, and this study provided a firm foundation for further work in this area.
L P Yang - One of the best experts on this subject based on the ideXlab platform.
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wear mechanisms of micro drills during dry high speed drilling of pcb
Journal of Materials Processing Technology, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In this paper, micro-drills with diameters of 0.1–0.3 mm were used to drill printed circuit boards (PCBs) with a highest spindle speed of 300 krpm. To study the wear mechanisms of PCB micro-drills, micro-drill morphology was observed, and the flank wear of the micro-drills was measured. The factors affecting flank wear were studied. In addition, hole wall roughness, Nail Head formation, and the accuracy of hole location were measured and analysed to determine how micro-drill wear influenced hole quality. It was found that abrasion was the main mechanism controlling the deterioration of cemented tungsten carbide micro-drills. The aggressive rubbing by glass fibre broken chips and reinforcing fillers, and the diffusion of cobalt caused abrasive wear of the flank, the chisel edge, the rake face, and the minor flank of the micro-drills. Resin that was softened by cutting heat would adhere to the micro-drills, which decreased chip removal and the accuracy of hole location. Micro-drill wear was inclined to cause Nail Heads and decrease the accuracy of hole location.
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characteristics of chip formation in the micro drilling of multi material sheets
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In order to meet the requirements of electronic product miniaturisation, the use of thinner and smaller printed circuit boards (PCBs) will be required. To achieve this, many more micro-holes must be drilled in a smaller area than before. PCBs are anisotropic multi-material sheets consisting of a dielectric layer (resin/glass fibre cloth) and a high purity metal conductor (copper foil). It is difficult to achieve high machining precision, surface quality, drilling efficiency and long drill life when drilling PCB micro-holes. In this study, micro-drills with a diameter of 0.1 mm were used to drill the PCBs at rotational speeds of up to 300 krpm. The drilling process was digitally photographed. The chip morphology and the hole wall were observed. The quality of the hole wall, such as hole wall roughness and Nail Head and exit burr formation were observed and measured. The influence of drilling condition on the drilling process and hole quality were studied. It was found that the morphology of the chips and the hole wall surface depended on the material properties of the printed circuit board. Chips were formed normally as conical helical chips from the aluminium entry board, conical helical chips from the copper foil and discontinuous chips from the glass fibre and softened resin. The hole wall through the copper foil seemed much smoother than that of resin/glass fibre cloth layer. However, Nail Heads and burrs were formed at the copper foil layers, which decreased the hole quality. Chip morphology and hole quality were affected by feed rate, spindle speed and tool wear. The basic removal mechanism of the PCB micro-holes was analysed, and this study provided a firm foundation for further work in this area.
Chengyong Wang - One of the best experts on this subject based on the ideXlab platform.
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wear mechanisms of micro drills during dry high speed drilling of pcb
Journal of Materials Processing Technology, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In this paper, micro-drills with diameters of 0.1–0.3 mm were used to drill printed circuit boards (PCBs) with a highest spindle speed of 300 krpm. To study the wear mechanisms of PCB micro-drills, micro-drill morphology was observed, and the flank wear of the micro-drills was measured. The factors affecting flank wear were studied. In addition, hole wall roughness, Nail Head formation, and the accuracy of hole location were measured and analysed to determine how micro-drill wear influenced hole quality. It was found that abrasion was the main mechanism controlling the deterioration of cemented tungsten carbide micro-drills. The aggressive rubbing by glass fibre broken chips and reinforcing fillers, and the diffusion of cobalt caused abrasive wear of the flank, the chisel edge, the rake face, and the minor flank of the micro-drills. Resin that was softened by cutting heat would adhere to the micro-drills, which decreased chip removal and the accuracy of hole location. Micro-drill wear was inclined to cause Nail Heads and decrease the accuracy of hole location.
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characteristics of chip formation in the micro drilling of multi material sheets
International Journal of Machine Tools & Manufacture, 2012Co-Authors: Lijuan Zheng, Chengyong Wang, L P Yang, Yuexian SongAbstract:Abstract In order to meet the requirements of electronic product miniaturisation, the use of thinner and smaller printed circuit boards (PCBs) will be required. To achieve this, many more micro-holes must be drilled in a smaller area than before. PCBs are anisotropic multi-material sheets consisting of a dielectric layer (resin/glass fibre cloth) and a high purity metal conductor (copper foil). It is difficult to achieve high machining precision, surface quality, drilling efficiency and long drill life when drilling PCB micro-holes. In this study, micro-drills with a diameter of 0.1 mm were used to drill the PCBs at rotational speeds of up to 300 krpm. The drilling process was digitally photographed. The chip morphology and the hole wall were observed. The quality of the hole wall, such as hole wall roughness and Nail Head and exit burr formation were observed and measured. The influence of drilling condition on the drilling process and hole quality were studied. It was found that the morphology of the chips and the hole wall surface depended on the material properties of the printed circuit board. Chips were formed normally as conical helical chips from the aluminium entry board, conical helical chips from the copper foil and discontinuous chips from the glass fibre and softened resin. The hole wall through the copper foil seemed much smoother than that of resin/glass fibre cloth layer. However, Nail Heads and burrs were formed at the copper foil layers, which decreased the hole quality. Chip morphology and hole quality were affected by feed rate, spindle speed and tool wear. The basic removal mechanism of the PCB micro-holes was analysed, and this study provided a firm foundation for further work in this area.
Eun Young Kim - One of the best experts on this subject based on the ideXlab platform.
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Head injury by pneumatic Nail gun a case report
Korean Journal of Neurotrauma, 2014Co-Authors: Tae Woo Kim, Yu Shik Shim, Dongkeun Hyun, Hyeonseon Park, Eun Young KimAbstract:A 56-year-old man had five Nail gun-shots on his skull due to attempted suicide and was transferred to the emergency room. Because the Nail Head played a role as a brake, the launched Nail made a hole in the skull but did not entirely pass through it. If major artery or sinuses are not involved, cautious retrieval after a small scalp incision can be performed and prophylactic antibiotics be administered for treatment.
