Investigation of Drill Hole Quality of Multi-Layer PWBs for High Current Capacity

2007 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Kenichi Mori ◽  
Yuusuke Itagaki
Keyword(s):  
Copper Foil ◽  
Drill Hole ◽  
Foil Thickness ◽  
Electronic Systems ◽  
Hole Quality ◽  
Large Current ◽  
Drill Holes ◽  
Objective Variable ◽  
Chip Load ◽  
Through Hole

Recently, as a result of changes in the automotive industry, a large number of electronic systems have been installed in cars. The thickness of the copper foil used for printed wiring boards (PWBs) has tended to increase in response to the large current capacity required for such electronic equipment. Therefore, the nail head generated in the inner layer copper foil was examined with respect to the influence of the thickness of the copper foil on the through-hole quality. In the present study, the size of the nail head generated in the copper foil after drilling a through hole was used as the objective variable. The explaining variables included drill wear, frequency, feed rate, chip load, drill temperature, copper foil thickness, copper foil cutting distance, and number of drill holes. We investigated the relationships between these explaining variables and the objective variable and found that the copper foil cutting distance was a very important parameter in generating nail heads. In addition, we found that the chip load is important for controlling nail head generation.

PATTERNS OF GASTROPOD MOLLUSK PREDATION ON BIVALVE MOLLUSKS ALONG THE UPPER TEXAS GULF COAST

2018 ◽  
Vol 70 (1) ◽  
Author(s):  
Serena J. Randolph ◽  
Alan D. Maccarone
Keyword(s):  
Shell Thickness ◽  
Prey Species ◽  
Gulf Coast ◽  
Prey Selection ◽  
Drill Hole ◽  
The United States ◽  
Hole Diameter ◽  
Bivalve Mollusks ◽  
Collection Site ◽  
Drill Holes

Abstract Predation on bivalve mollusks by gastropod mollusks is common in coastal regions of the United States; however, few previous studies have examined whether drilling gastropods exhibit prey selection. In 2016, shells with small holes drilled by as many as two gastropod predators were collected at three sites separated by 30 km along the Texas Upper Gulf Coast on the Bolivar Peninsula (29° 40′N, 94° 90′W). The likeliest predators in these waters are the southern oyster drill (Stramonita haemastoma Linnaeus 1767) and the moon snail (Neverita duplicate Say 1822). Collected shells were identified to species and measurements were taken to examine statistical relationships between predators and prey species. These measurements included drill-hole diameter, shell thickness, drill-hole completeness, number of drill attempts, and collection site. Across the three locations, 17 different species of shells with drill holes were collected; of these, we focused on the ten most abundant species (n = 277 shells). The sample showed high variation in drill-hole diameter, shell thickness, and drill-hole completeness. Both the total number of holes and mean drill-hole diameter differed significantly among prey species (ANOVA, both P < 0.0001). In addition, drill-hole diameter correlated directly with prey shell thickness (P < 0.0001). Shells whose drill holes were complete were significantly thinner than shells with incomplete holes (P < 0.0001). Mean prey shell thickness, mean drill-hole diameter, and mean number of drill holes all differed significantly by collection site (all P < 0.0001). Ecological and morphological implications related to gastropod predation on mollusks are discussed.

Cu-Direct Laser Drilling of Blind Via-Hole in Multi-Layer PWBs: Influence of Surface Treatment on Drilled Hole Quality

2009 ◽  
Author(s):  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
Keiji Ogawa ◽  
Tsukasa Ayuzawa
Keyword(s):  
Surface Treatment ◽  
Co2 Laser ◽  
Copper Foil ◽  
Laser Energy ◽  
Copper Surface ◽  
Laser Drilling ◽  
Hole Quality ◽  
Direct Laser ◽  
Overhang Length ◽  
Direct Drilling

This report describes the quality assessment of Blind Via Holes (BVHs) of Printed Wiring Boards (PWBs) drilled by a CO2 laser using Cu-direct drilling. In the Cu-direct drilling method, the copper foil and the build-up layer are melted at the same time, and the surface is treated to increase the laser energy absorbed by the copper foil since an untreated copper surface reflects most of the 10.6-μm-wavelength CO2 laser beam. However, there are few reports dealing with Cu-direct laser drilling of PWBs. In addition, when copper and resin with different processing thresholds are drilled at the same time, occurrences of a defect called overhang have been observed. So, in this report, first we propose a new method using thermography to measure the absorptance of a PWB surface for a CO2 laser. Moreover, we investigate how surface treatment of the outer copper foil influences the quality of a laser-drilled hole. Then, we observe the circumference of a point irradiated with the CO2 laser and explain how melting processes are different from surface treatment. Finally, based on the research we establish a method in order to cut down the overhang length as a parameter of drilled-hole quality. We also show that a high absorptance improves BVH quality.

Qualitätssteigerung von Bohrungen in Faserkunststoffverbunden*/Increased quality of bores in fiber reinforced polymers

2015 ◽  
Vol 105 (07-08) ◽  
pp. 501-507
Author(s):  
L. Heberger ◽  
S. Nissle ◽  
M. Gurka ◽  
B. Kirsch ◽  
J. C. Aurich
Keyword(s):  
Carbon Fiber ◽  
Computer Tomography ◽  
Drill Hole ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Hole Quality ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Carbon Fiber Reinforced

Beim Bohren von kohlefaserverstärktem Kunststoff treten verstärkt Schädigungen wie Delaminationen und Faserüberstände auf. Mit dem Ziel die Bohrlochqualität zu verbessern, wurde der Einfluss der Werkstückeinspannung hinsichtlich Einspanngeometrie, -kraft und -material untersucht. Zusätzlich zur konventionellen optischen Delaminationsmessung wurde die äußere und die innere Delamination mittels Mikrocomputertomografie analysiert. Durch eine Optimierung der Einspannung konnte die Bohrlochqualität gesteigert werden.   When drilling carbon fiber reinforced polymers damages like delamination and fiber protrusion appear. Aiming to improve the drill hole quality, the influence of the fastening device with respect to fastening geometry, force and material is analyzed. In addition to the conventional optical delamination measurement, the outer and inner delamination is investigated by micro computer tomography. The optimization of the fastening device leads to a higher drill hole quality.

Large Drill Holes Are Still Present in the Long Term After Arthroscopic Bankart Repair With Absorbable Tacks: An 18-Year Randomized Prospective Study

2020 ◽  
Vol 48 (8) ◽  
pp. 1865-1872
Author(s):  
Christina Chrysanthou Constantinou ◽  
Ninni Sernert ◽  
Lars Rostgård-Christensen ◽  
Jüri Kartus
Keyword(s):  
Study Groups ◽  
Drill Hole ◽  
Ct Images ◽  
Bankart Repair ◽  
Plain Radiographs ◽  
Arthroscopic Bankart Repair ◽  
Absorbable Tacks ◽  
Drill Holes

Background: Studies have demonstrated the development of an osseous reaction at the drill sites of anchors after arthroscopic shoulder surgery. Purpose: To investigate the drill-hole size at 18 years after arthroscopic Bankart repair using either fast polygluconate acid (PGA) or slow polylevolactic acid (PLLA) absorbable tacks and to compare the functional outcomes and development of osteoarthritis. Study design: Randomized controlled trial; Level of evidence, 2. Methods: 40 patients with unidirectional anterior shoulder instability, treated with arthroscopic Bankart repair, were randomized into the PGA group (n = 20) or the PLLA group (n = 20). Plain radiographs of both shoulders, as well as computed tomography (CT) images of the operated shoulder, were used to evaluate the drill-hole size, volume, and degenerative changes. Functional outcomes were assessed by use of the Rowe score, Constant score, and Western Ontario Shoulder Instability (WOSI) index. Results: Of the 40 patients, 32 patients returned for the follow-up (15 PGA and 17 PLLA). No significant differences were found in the population characteristics between the study groups. The mean follow-up time was 18 years for both groups. No significant differences were seen in range of motion, strength in abduction, or Constant, Rowe, and WOSI scores between the groups. Recurrence rate was 33% in the PGA group and 6% in the PLLA group during the follow-up period ( P = .07). The drill-hole appearance on plain radiographs (invisible/hardly visible/visible/cystic) was 11/2/2/0 and 6/5/5/1 for the PGA and PLLA groups, respectively ( P = .036). The mean ± SD drill-hole volume as estimated on CT images was 89 ± 94 and 184 ± 158 mm3 in the PGA and PLLA groups, respectively ( P = .051). Degenerative changes (normal/minor/moderate/severe) on plain radiographs were 7/4/4/0 and 3/8/5/1 for the PGA and PLLA groups, respectively ( P = .21), and on CT images were 5/7/3/0 and 2/6/6/3 for the PGA and PLLA groups, respectively ( P = .030). Conclusion: This long-term follow-up study demonstrated that the PLLA group had significantly more visible drill holes than the PGA group on plain radiographs. However, this difference was not evident on CT imaging, with both groups having several visible cystic drill holes and a substantial drill-hole volume defect. No significant differences were found between the study groups in terms of clinical outcomes.

scholarly journals Drilling Tool Geometry Effects on the Hole Quality of Glare

2020 ◽  
Vol 8 (4S4) ◽  
pp. 156-159
Keyword(s):  
Structural Damage ◽  
Cutting Tool ◽  
Epoxy Composite ◽  
Drill Hole ◽  
Tool Geometry ◽  
Drill Bit ◽  
Machining Parameters ◽  
Hole Quality ◽  
Drilling Tool

Recently machining of hybrid stacking materials are much interested and challenging in manufacturing domains. Mostly, drill hole quality depends the machining parameters and type of cutting tool. This work investigates the experimental study for effects of drill bit geometry on hole quality of glass laminate aluminum reinforced epoxy (GLARE). GLARE have manufactured by alternative stacking of aluminum (AA7475) and glass fiber (E-glass)/epoxy composite through compression molding machine. Machining of GLARE by using of Computer numerical controller. Hole quality were studied with the aid of optical microscopic. Results show that a drill tip geometry to promote the reduction of delamination and structural damage. Superior hole quality is achieved with 2 fluted drill bit than 3 fluted drill bit.

Geometric Optimization of Crack Arresting Holes in an Operational Component

2010 ◽  
Author(s):  
Onome Scott-Emuakpor ◽  
Tommy George ◽  
Charles Cross
Keyword(s):  
Crack Growth ◽  
Fatigue Testing ◽  
Growth Arrest ◽  
Real Life ◽  
Design Procedure ◽  
Drill Hole ◽  
Geometric Optimization ◽  
Foreign Object Damage ◽  
Square Plate ◽  
Drill Holes

Crack-growth arrest is analyzed in this study with the simulation of real-life fatigue of a structure during service. Unlike conventional crack-growth arrest studies, this research does not analyze an opening mode (Mode I) crack extension from an induced crack-tip specimen. The work in this analysis focuses on designing drill-holes into a structure, without a preexisting crack, that will operate under cyclic loads. The purpose of the holes is to prevent through-crack propagation if a crack initiates during service of the structure. Prevention reduces the possibility of a phenomenon like Foreign Object Damage (FOD) by a fragment of a fractured structure in heavy operating machinery and over-looked cracks during routine inspections. The drill-hole design procedure for crack growth arrest explores the use of two, three and four-hole configurations as well as the effect of inserting hard Viton-rubber pins into each drill hole of a square plate test specimen. Each specimen configuration is geometrically designed with the following in mind: minimized the hole-to-fatigue zone stress ratio, minimize damping loss between the original and the new designs with holes and pins, and experimentally validating the theory of the crack arresting methods. The geometric optimization for the square plate specimen was developed in accordance with a vibration-based fatigue testing method for uniaxial bending, which is the benchmark method for this study.

A new technique for sampling water and gas from deep drill holes

1986 ◽  
Vol 23 (9) ◽  
pp. 1450-1454 ◽  
Author(s):  
Pekka A. Nurmi ◽  
Ilmo T. Kukkonen
Keyword(s):  
Drill Hole ◽  
Back Pressure ◽  
New Technique ◽  
Dissolved Gases ◽  
A New Technique ◽  
Drill Holes ◽  
Water Profile

A new technique for sampling water and gas from deep (500–1500 m) drill holes is described. The principle of the technique is to raise a continuous column of water inside a thin polyamide tube with a back-pressure valve at the lower end and with shutoff valves every 50 m. The equipment is easily assembled from standard parts. Sampling can be performed by three people without mechanical apparatus. Descent to 1000 m takes 2 hours and retrieval 1 hour. The method makes it possible to obtain a practically undisturbed continuous water profile from a drill hole. Dissolved gases remaining inside the tube can be sampled at the surface. To demonstrate the efficiency of the technique, selected results from the deepest drill hole in Finland, having a vertical depth of 1100 m, are presented.

OS1502 Influence of Foil Thickness on Mechanical Property of Pure Copper Foil

2011 ◽  
Vol 2011 (0) ◽  
pp. _OS1502-1_-_OS1502-3_
Author(s):  
Tomoyuki FUJII ◽  
Yasuhiro NODA ◽  
Keiichiro TOHGO ◽  
Yoshinobu SHIMAMURA
Keyword(s):  
Mechanical Property ◽  
Copper Foil ◽  
Pure Copper ◽  
Foil Thickness
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