The Experts below are selected from a list of 31038 Experts worldwide ranked by ideXlab platform
Toshiki Hirogaki - One of the best experts on this subject based on the ideXlab platform.
-
Microvia Formation for Multi-Layer PWB by Laser Direct Drilling: Improvement of Drilled Hole Quality of GFRP Plates
ASME 2012 International Manufacturing Science and Engineering Conference, 2012Co-Authors: Keiji Ogawa, Eiichi Aoyama, Toshiki Hirogaki, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia that are called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), which is direct drilling of the outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are simultaneously Drilled, an overhang defect occurs on the Drilled Hole. On the other hand, aramid fiber reinforced plastics (AFRP) have been replaced by glass fiber reinforced plastics (GFRP) as the material used for the build-up layer because of its cost performance. Moreover, the PWB quality of the particle incrustations around the Drilled Holes has problems in the manufacturing process. However, the LDD process of such a composite has not been clarified. Therefore, we investigated it by detailed observation using a high-speed camera. We estimated the overhang length using the finite element method (FEM) and experimentally and analytically evaluated the effects of filler contented build-up layers. As a result, we improved Drilled-Hole quality by using prototype PWBs made of GFRP with filler in the build-up layer.© 2012 ASME
-
microvia formation for multi layer pwb by laser direct drilling improvement of Hole quality by silica fillers in build up layer
ASME 2011 International Manufacturing Science and Engineering Conference Volume 2, 2011Co-Authors: Keiji Ogawa, Toshiki Hirogaki, Kuniyoshi Obata, Eiichi Aoyama, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), drilling directly outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are Drilled at the same time, an overhang defect occurs on the Drilled Hole. However, the overhang generation mechanism has not been clarified. Therefore, we investigated it by detailed observation of the Drilled-Hole section. Moreover, the overhang length was estimated using the finite element method (FEM). Influences of surface treatment of outer copper foil and thermal properties of the build-up layer were evaluated experimentally and analytically. Consequently, an experiment with a prototype PWB with silica filler added in the build-up layer was carried out. Using the prototype PWBs, the overhang was reduced as shown in FEM analysis results.Copyright © 2011 by ASME
-
direct laser drilling in copper clad printed wiring boards effect of surface treatment on Drilled blind via Hole quality
Transactions of the Japan Society of Mechanical Engineers. A, 2008Co-Authors: Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa, Shogo Matsutani, Tsukasa AyuzawaAbstract:Micro-via drilling technology using a laser has become the dominant method of drilling smaller blind via-Holes in copper clad multi-layer printed wiring boards (PWBs). Cu-direct laser drilling has attracted attention as a new method. However, the defect of overhang occurs when copper and resin, having different processing thresholds, are Drilled at the same time. The absorptance is an important factor for Cu-direct laser drilling. Therefore, we propose a new method using thermography to measure the absorptance of a PWB's surface for a CO2laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-Drilled Hole. Two kinds of surface treatment, roughening and application of black-oxide, were attempted as ways to improve the absorptance of a surface for the laser. As a result, it was found that not only the surface absorptance but also the method of surface treatment affects the quality of a Drilled Hole.
-
Improvement of micro-Drilled Hole quality for printed wiring boards
Journal of Materials Processing Technology, 2007Co-Authors: Heisaburo Nakagawa, Keiji Ogawa, A. Kihara, Toshiki HirogakiAbstract:Abstract In the current manufacturing of printed wiring boards (PWBs), micro-drills are generally used to make smaller diameter through-Holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by Hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of Drilled Hole wall is one of the important factors affecting the plating quality. However, there are many factors, which can affect complexly the surface roughness, such as drilling conditions and material properties of PWBs. On the other hand, few reports previously describe the factors which influence on the micro-Drilled Hole wall quality of PWBs. The purpose of this paper is to indicate the proper method in order to improve the Drilled Hole wall quality by clarifying the factors which affect the surface roughness of micro-Drilled Hole wall of PWBs. First, the drill temperature was evaluated in drilling monitored by a thermography under various drilling conditions such as cutting speed and feed rate in order to show the influence of the temperature in drilling on the Drilled Hole wall quality. Second, the thrust force and the torque in drilling were measured with a dynamometer in order to evaluate the cutting phenomenon in detail and to clarify the relationship between drilling process and the variation of cutting forces. Especially, the influence of the workload, calculated using measured torque in drilling, on the drill temperature and the surface roughness of Drilled Hole wall was evaluated. As results, the following conclusions were reached: (1) the surface roughness of Drilled Hole wall increases with the drill temperature in drilling. (2) The drill temperature tends to increase with the workload on drill caused by friction between Hole wall and the land or margin of drill. Therefore, the reduction of the workload by the friction seems to be effective in order to obtain the high quality micro-Drilled Hole wall.
-
Quality Control of Micro-Drilled Hole Wall of PWBs Using Data-Mining
Volume 3: 25th Computers and Information in Engineering Conference Parts A and B, 2005Co-Authors: Eiichi Aoyama, Toshiki Hirogaki, Keiji Ogawa, Tsuyoshi Otsuka, Katsutoshi YamauchiAbstract:In the manufacturing of printed wiring boards (PWBs), various methods have been developed in order to improve the circuit packaging density. Micro-drills are generally used to make smaller diameter through-Holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by Hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of Drilled Hole wall is one of the important factors affecting the plating quality. The purpose of the present report is to apply data-mining to the surface roughness data of Drilled through-Hole walls, and to elucidate the factors required to control the Drilled Hole quality. The following conclusions were obtained. (1) The data-mining aided by a computer was found to be effective to control the Drilled Hole wall quality in the PWBs manufacturing. (2) It was clear that the surface roughness of Drilled Hole walls depended on three factors: the drill temperature, cutting distance, and the width of the fiber bundle of weft yarn.Copyright © 2005 by ASME
Keiji Ogawa - One of the best experts on this subject based on the ideXlab platform.
-
Microvia Formation for Multi-Layer PWB by Laser Direct Drilling: Improvement of Drilled Hole Quality of GFRP Plates
ASME 2012 International Manufacturing Science and Engineering Conference, 2012Co-Authors: Keiji Ogawa, Eiichi Aoyama, Toshiki Hirogaki, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia that are called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), which is direct drilling of the outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are simultaneously Drilled, an overhang defect occurs on the Drilled Hole. On the other hand, aramid fiber reinforced plastics (AFRP) have been replaced by glass fiber reinforced plastics (GFRP) as the material used for the build-up layer because of its cost performance. Moreover, the PWB quality of the particle incrustations around the Drilled Holes has problems in the manufacturing process. However, the LDD process of such a composite has not been clarified. Therefore, we investigated it by detailed observation using a high-speed camera. We estimated the overhang length using the finite element method (FEM) and experimentally and analytically evaluated the effects of filler contented build-up layers. As a result, we improved Drilled-Hole quality by using prototype PWBs made of GFRP with filler in the build-up layer.© 2012 ASME
-
microvia formation for multi layer pwb by laser direct drilling improvement of Hole quality by silica fillers in build up layer
ASME 2011 International Manufacturing Science and Engineering Conference Volume 2, 2011Co-Authors: Keiji Ogawa, Toshiki Hirogaki, Kuniyoshi Obata, Eiichi Aoyama, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), drilling directly outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are Drilled at the same time, an overhang defect occurs on the Drilled Hole. However, the overhang generation mechanism has not been clarified. Therefore, we investigated it by detailed observation of the Drilled-Hole section. Moreover, the overhang length was estimated using the finite element method (FEM). Influences of surface treatment of outer copper foil and thermal properties of the build-up layer were evaluated experimentally and analytically. Consequently, an experiment with a prototype PWB with silica filler added in the build-up layer was carried out. Using the prototype PWBs, the overhang was reduced as shown in FEM analysis results.Copyright © 2011 by ASME
-
evaluation and improvement of micro Drilled Hole wall quality in printed wiring boards made of glass fiber reinforced plastics
ASME 2009 InterPACK Conference collocated with the ASME 2009 Summer Heat Transfer Conference and the ASME 2009 3rd International Conference on Energy , 2009Co-Authors: Keiji Ogawa, Heisaburo Nakagawa, Masatoshi MatsudairaAbstract:With recent worldwide-use and the rapid spread of electric and electronic equipment, printed wiring boards (PWBs) are being miniaturized and made multifunctional. Miniaturizing the equipment and making it high performance are accompanied by an increase in the number of small diameter through Holes for circuit connections available to the PWBs. Such tendency needs the large number of smaller diameter drilling with shorter pitches. Moreover, the improvement of Drilled-Hole wall quality for PWBs might be demanded by such trends. Here, PWBs are often made of fiber-reinforced plastics (FRP) for the insulating layers and copper foil for the circuit layers. A woven glass fiber cloth is generally used for PWBs. Therefore, delamination might occur during drilling and affect the surface roughness of the Drilled-Hole wall. Such wrong surface roughness of Drilled-Hole wall should be avoided because it might reduce the reliability of insulating between next Holes by ion migration of copper plating progressing along the delamination. Revealing of its mechanism is expected to be more important with smaller diameter with smaller electric devices. However, it might be difficult because the micr-drilling of FRP shows is a complex phenomenon because it consists of different materials. Therefore, this paper investigates the proper method to improve Drilled-Hole wall quality by evaluating the drill temperature rising mechanism and the surface generation mechanism of micro-Drilled-Hole walls of PWBs made of GFRP. The following results were reached: (1) A drill temperature rising mechanism was conducted. (2) Drill temperature tends to increase with the frictional torque between the Hole wall and the margin part of drill. (3) Frictional torque increases with the spring-back of the Drilled-Hole wall during drilling. (4) The surface roughness of the Drilled-Hole wall of the GFRP plate is affected by the breakdown of the glass fiber and is mainly caused by the cutting edge of the outer corner except the margin part of the drill. (5) A drilling method with higher fiber bonding strength, such as drilling with compressing PWBs in the thickness direction, effectively improves the Drilled-Hole wall quality.Copyright © 2009 by ASME
-
direct laser drilling in copper clad printed wiring boards effect of surface treatment on Drilled blind via Hole quality
Transactions of the Japan Society of Mechanical Engineers. A, 2008Co-Authors: Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa, Shogo Matsutani, Tsukasa AyuzawaAbstract:Micro-via drilling technology using a laser has become the dominant method of drilling smaller blind via-Holes in copper clad multi-layer printed wiring boards (PWBs). Cu-direct laser drilling has attracted attention as a new method. However, the defect of overhang occurs when copper and resin, having different processing thresholds, are Drilled at the same time. The absorptance is an important factor for Cu-direct laser drilling. Therefore, we propose a new method using thermography to measure the absorptance of a PWB's surface for a CO2laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-Drilled Hole. Two kinds of surface treatment, roughening and application of black-oxide, were attempted as ways to improve the absorptance of a surface for the laser. As a result, it was found that not only the surface absorptance but also the method of surface treatment affects the quality of a Drilled Hole.
-
Improvement of micro-Drilled Hole quality for printed wiring boards
Journal of Materials Processing Technology, 2007Co-Authors: Heisaburo Nakagawa, Keiji Ogawa, A. Kihara, Toshiki HirogakiAbstract:Abstract In the current manufacturing of printed wiring boards (PWBs), micro-drills are generally used to make smaller diameter through-Holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by Hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of Drilled Hole wall is one of the important factors affecting the plating quality. However, there are many factors, which can affect complexly the surface roughness, such as drilling conditions and material properties of PWBs. On the other hand, few reports previously describe the factors which influence on the micro-Drilled Hole wall quality of PWBs. The purpose of this paper is to indicate the proper method in order to improve the Drilled Hole wall quality by clarifying the factors which affect the surface roughness of micro-Drilled Hole wall of PWBs. First, the drill temperature was evaluated in drilling monitored by a thermography under various drilling conditions such as cutting speed and feed rate in order to show the influence of the temperature in drilling on the Drilled Hole wall quality. Second, the thrust force and the torque in drilling were measured with a dynamometer in order to evaluate the cutting phenomenon in detail and to clarify the relationship between drilling process and the variation of cutting forces. Especially, the influence of the workload, calculated using measured torque in drilling, on the drill temperature and the surface roughness of Drilled Hole wall was evaluated. As results, the following conclusions were reached: (1) the surface roughness of Drilled Hole wall increases with the drill temperature in drilling. (2) The drill temperature tends to increase with the workload on drill caused by friction between Hole wall and the land or margin of drill. Therefore, the reduction of the workload by the friction seems to be effective in order to obtain the high quality micro-Drilled Hole wall.
Koichi Tsuchiya - One of the best experts on this subject based on the ideXlab platform.
-
role of strain gradient on the formation of nanocrystalline structure produced by severe plastic deformation
Journal of Alloys and Compounds, 2007Co-Authors: Jinguo Li, Minoru Umemoto, Yoshikazu Todaka, Koichi TsuchiyaAbstract:In the present study, the formation of nanocrystalline structure by high speed drilling was investigated. Several micrometers thick nanocrystalline layer was observed at the top surface of Drilled Hole. Nanocrystalline layers showed high hardness and good thermal stability. The estimation of necessary dislocation density to produce nanocrystalline structure and the comparison between the estimated and measured strain gradient near the Drilled Hole surface was conducted. It is proposed that deformation with a large strain gradient is an important condition to produce nanocrystalline structure.
-
a microstructural investigation of the surface of a Drilled Hole in carbon steels
Acta Materialia, 2007Co-Authors: Minoru Umemoto, Yoshikazu Todaka, Koichi TsuchiyaAbstract:The microstructure of the surface of Drilled Holes generated under different drilling conditions in carbon steels has been investigated. It is found that the surface microstructure depends strongly on the drilling parameters and the hardness of the matrix. White etching layers, composed of an equiaxed nanocrystalline structure layer with an average grain size of the order of several 10 nm and a submicron grained layer containing fresh martensite along the depth, formed on the Hole surfaces during drilling at moderate to high cutting speed in carbon steels with high matrix hardness. The existence of a high content of austenite at the Hole surface suggests that dynamic phase transformation (DPT) from body-centered cubic to face-centered cubic occurred during high-speed drilling. It is proposed that the ultrafine structure layer on the surface of a Drilled Hole is produced by severe plastic deformation-induced DPT together with a large strain gradient and high strain rate. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Eiichi Aoyama - One of the best experts on this subject based on the ideXlab platform.
-
Microvia Formation for Multi-Layer PWB by Laser Direct Drilling: Improvement of Drilled Hole Quality of GFRP Plates
ASME 2012 International Manufacturing Science and Engineering Conference, 2012Co-Authors: Keiji Ogawa, Eiichi Aoyama, Toshiki Hirogaki, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia that are called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), which is direct drilling of the outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are simultaneously Drilled, an overhang defect occurs on the Drilled Hole. On the other hand, aramid fiber reinforced plastics (AFRP) have been replaced by glass fiber reinforced plastics (GFRP) as the material used for the build-up layer because of its cost performance. Moreover, the PWB quality of the particle incrustations around the Drilled Holes has problems in the manufacturing process. However, the LDD process of such a composite has not been clarified. Therefore, we investigated it by detailed observation using a high-speed camera. We estimated the overhang length using the finite element method (FEM) and experimentally and analytically evaluated the effects of filler contented build-up layers. As a result, we improved Drilled-Hole quality by using prototype PWBs made of GFRP with filler in the build-up layer.© 2012 ASME
-
microvia formation for multi layer pwb by laser direct drilling improvement of Hole quality by silica fillers in build up layer
ASME 2011 International Manufacturing Science and Engineering Conference Volume 2, 2011Co-Authors: Keiji Ogawa, Toshiki Hirogaki, Kuniyoshi Obata, Eiichi Aoyama, Tsukasa AyuzawaAbstract:Microvia formation technology using lasers has become the dominant method for drilling microvia called blind via-Holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), drilling directly outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are Drilled at the same time, an overhang defect occurs on the Drilled Hole. However, the overhang generation mechanism has not been clarified. Therefore, we investigated it by detailed observation of the Drilled-Hole section. Moreover, the overhang length was estimated using the finite element method (FEM). Influences of surface treatment of outer copper foil and thermal properties of the build-up layer were evaluated experimentally and analytically. Consequently, an experiment with a prototype PWB with silica filler added in the build-up layer was carried out. Using the prototype PWBs, the overhang was reduced as shown in FEM analysis results.Copyright © 2011 by ASME
-
direct laser drilling in copper clad printed wiring boards effect of surface treatment on Drilled blind via Hole quality
Transactions of the Japan Society of Mechanical Engineers. A, 2008Co-Authors: Toshiki Hirogaki, Eiichi Aoyama, Keiji Ogawa, Shogo Matsutani, Tsukasa AyuzawaAbstract:Micro-via drilling technology using a laser has become the dominant method of drilling smaller blind via-Holes in copper clad multi-layer printed wiring boards (PWBs). Cu-direct laser drilling has attracted attention as a new method. However, the defect of overhang occurs when copper and resin, having different processing thresholds, are Drilled at the same time. The absorptance is an important factor for Cu-direct laser drilling. Therefore, we propose a new method using thermography to measure the absorptance of a PWB's surface for a CO2laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-Drilled Hole. Two kinds of surface treatment, roughening and application of black-oxide, were attempted as ways to improve the absorptance of a surface for the laser. As a result, it was found that not only the surface absorptance but also the method of surface treatment affects the quality of a Drilled Hole.
-
Quality Control of Micro-Drilled Hole Wall of PWBs Using Data-Mining
Volume 3: 25th Computers and Information in Engineering Conference Parts A and B, 2005Co-Authors: Eiichi Aoyama, Toshiki Hirogaki, Keiji Ogawa, Tsuyoshi Otsuka, Katsutoshi YamauchiAbstract:In the manufacturing of printed wiring boards (PWBs), various methods have been developed in order to improve the circuit packaging density. Micro-drills are generally used to make smaller diameter through-Holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by Hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of Drilled Hole wall is one of the important factors affecting the plating quality. The purpose of the present report is to apply data-mining to the surface roughness data of Drilled through-Hole walls, and to elucidate the factors required to control the Drilled Hole quality. The following conclusions were obtained. (1) The data-mining aided by a computer was found to be effective to control the Drilled Hole wall quality in the PWBs manufacturing. (2) It was clear that the surface roughness of Drilled Hole walls depended on three factors: the drill temperature, cutting distance, and the width of the fiber bundle of weft yarn.Copyright © 2005 by ASME
-
Drilled Hole damage of small diameter drilling in printed wiring board
Journal of Materials Processing Technology, 2001Co-Authors: Eiichi Aoyama, Hiromich Nobe, Toshiki HirogakiAbstract:Abstract Of late, it has become necessary to improve the packaging density of printed wiring board (PWB), because the demand for size reduction of the electric devices is increasing. Therefore, the pitches between through Holes in electric circuits have become fine for the high package density. On the other hand, various forms of damage occur around the Holes after drilling. Much research has been done on internal damage in order to prevent the reduction of the insulation resistance between the Holes after through Hole plating, and the blow Holes after soldering. This study is about the damage factors around the Drilled Hole wall in small diameter drilling of an PWB in order to prevent the ion migration between the Holes. It is shown that there are two important factors of internal damage around the Drilled Hole: (1) the relative angles between cutting directions and fibre directions; (2) fibre bundle thickness of glass cloth at the Drilled Hole wall. In particular, it is demonstrated that the reduction of the fibre bundle thickness is effective to decrease the internal damage of Drilled Hole.
M Gunjima - One of the best experts on this subject based on the ideXlab platform.
-
investigation on cutting mechanism in small diameter drilling for gfrp thrust force and surface roughness at Drilled Hole wall
Composite Structures, 1997Co-Authors: Keiji Ogawa, Toshiki Hirogaki, Eiichi Aoyama, Hiromich Nobe, Hisahiro Inoue, Youji Kitahara, Tsutao Katayama, M GunjimaAbstract:This study describes the relation between the cutting force and the surface roughness of a Drilled Hole wall in small-diameter drilling of GFRP for a printed wiring board. In order to investigate the characteristics of small diameter drilling for GFRP, the surface of the Drilled Hole wall is observed by SEM, and the surface roughness along the feed direction is measured at various edge position angles of the Drilled Hole. The cutting force during drilling is measured. Moreover, the thrust force is devided into two components (the static component and the dynamic component). It is shown that the dynamic components are related with the surface roughness of the Drilled Hole wall. In conclusion, it is found that the major cutting edge of the drill is more influential in the quality of the Drilled Hole wall than the chisel edge of the drill in small diameter drilling of PWB.
