scholarly journals Experimental and Numerical Simulation Study of the Vibration Properties of Thin Copper Films Bonded to FR4 Composite

2020 ◽  
Vol 10 (15) ◽  
pp. 5197
Author(s):  
Sufyan A. Azam ◽  
Alex Fragoso
Keyword(s):  
Printed Circuit Boards ◽  
Copper Films ◽  
Circuit Boards ◽  
Good Correspondence ◽  
Printed Circuit ◽  
Modal Properties ◽  
Aspect Ratios ◽  
Different Diameters ◽  
First Time ◽  
Bare Copper

Printed circuit boards constitute the basis of most electronic devices and are mainly fabricated of thin copper films bounded to fiber epoxy laminates, such as FR4. Vibrational stress can induce device failure, and hence, studies addressing their modal properties have important applications. In this paper, cantilever samples made of bare copper bounded to FR4 have been studied to analyze, for the first time, the vibration behavior of specimens with different aspect ratios, with and without central holes of different diameters. Natural frequencies and damping ratios were determined experimentally and analytically using a finite element method for four groups of samples with a very good correspondence between both methods. The fundamental resonance frequency of all the specimens was found to be less than 40 Hz and the influence of a central hole was not significant to affect the modal properties.

Synergism of mechanical activation and sulfurization to recover copper from waste printed circuit boards

RSC Advances ◽  
2014 ◽  
Vol 4 (94) ◽  
pp. 51970-51976 ◽  
Author(s):  
Zhiyuan Ou ◽  
Jinhui Li
Keyword(s):  
Free Radical ◽  
Mechanical Activation ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Free Radical Theory ◽  
Radical Theory ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
First Time

This work proposed a synergistic route of mechanic activation and sulfurization to recover copper from waste printed circuit boards for the first time and take successful use of free radical theory in assessing the synergism mechanism.

Market volatility is a gift to the gold price

2019 ◽  
Keyword(s):  
Gold Mining ◽  
Printed Circuit Boards ◽  
Gold Price ◽  
Automotive Electronics ◽  
Circuit Boards ◽  
Content Type ◽  
Printed Circuit ◽  
The Us ◽  
Asset Classes ◽  
First Time

Significance Gold outperformed other asset classes, including US equities, last year for the first time since 2011. However, this was due more to gold's relatively low volatility than to spectacular price gains. After losing 8.5% in the first nine months of the year the gold price has risen by 9.0% since late September, driven largely by the dollar stuttering on speculation that the US Federal Reserve (Fed) might slow its interest rate tightening. Impacts Cryptoassets have failed to exhibit a negative correlation to mainstream assets and are unlikely to constitute a viable alternative to gold. The downturn in crypto mining infrastructure will cut gold demand as it is used in smartphones, game consoles and automotive electronics. China’s environmental regulations will hurt cyanide-dependent gold mining and reduce demand for gold for use in printed circuit boards. Freeport-owned Grasberg, the largest gold-copper mine, will reduce its volumes by over two-thirds in 2019 as output is moving underground.

Analysis of PCB via for Signal Integrity Using ANOVA

2013 ◽  
Vol 446-447 ◽  
pp. 956-960
Author(s):  
Shi Lei Zhou ◽  
Ya Lin Guan ◽  
Xin Kun Tang
Keyword(s):  
Printed Circuit Boards ◽  
Signal Integrity ◽  
Point Of View ◽  
Electromagnetic Simulation ◽  
Physical Aspect ◽  
Circuit Boards ◽  
Anova Analysis ◽  
Printed Circuit ◽  
Full Wave ◽  
Aspect Ratios

This paper based on ANOVA (ANalysis Of VAriance) presents an investigation in the design of signal via in multilayered printed circuit boards (PCB) technology from a signal integrity point of view. Using the concept of the orthogonal array (OA), different vias physical aspect ratios have been set in the analysis. The impacts of these parameters are investigated with the help for a full-wave electromagnetic simulation soft HFSS. This study demonstrates the factors which is the most influence on the signal integrity.

A Novel Route for Copper Recovery from Waste Printed Circuit Boards via Mechanochemistry

2015 ◽  
Vol 768 ◽  
pp. 569-575
Author(s):  
Zhi Yuan Ou ◽  
Jin Hui Li
Keyword(s):  
Copper Sulfide ◽  
Printed Circuit Boards ◽  
Milling Time ◽  
Iron Sulfide ◽  
Xrd Analysis ◽  
Copper Recovery ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
First Time

This paper mainly introduces a novel route for copper recovery from waste printed circuit boards (WPCBs) via mechanochemistry. Copper in the crust is most commonly present as copper-iron-sulfide and copper-sulfide minerals (about 80%) and there exist many methods to extract copper from cooper ores in mineral engineering. It seems an alternative to transform the metallic components in obsolete materials to their corresponding compounds common in nature. By means of mechanochemistry, copper and sulfur were verified to form into copper sulfide in the model experiment, where, meanwhile, the optimal ball milling time was determined (20 minutes). In the real experiment, WPCB fragments and sulfur were mixed and ground for 20 minutes, no copper was detected by XRD analysis but copper sulfide was left. After leaching in sulfuric acid (3M) and hydrogen peroxide (30 wt%), the yield of copper reached nearly 95% and, also, resin was conserved for further utilization. This paper, for the first time, reports the green recovery route combining mechanical activation and sulfurization and may provide an alternative in other studies of metal recovery.

scholarly journals Periodic Pulse Plating of Mid-Aspect Ratio Printed Circuit Boards for Enhanced Productivity

2020 ◽  
Vol 33 (2) ◽  
pp. 14-21
Author(s):  
Carmichael Gugliotti ◽  
Rich Bellemare ◽  
Andy Oh ◽  
Ron Blake
Keyword(s):  
Aspect Ratio ◽  
Printed Circuit Boards ◽  
High Volume ◽  
Pulse Plating ◽  
Circuit Boards ◽  
Throwing Power ◽  
Printed Circuit ◽  
Aspect Ratios ◽  
High Volume Production ◽  
Volume Production

ABSTRACT Pulse plating of copper has typically found use in the plating of very difficult, high aspect ratio printed circuit boards. Its ability to provide throwing power deep within through holes with aspect ratios as high as 30:1 is well established. This technology has long been thought of as a high technology, high cost, specialty process applicable only to high end products. This paper will discuss the advantages that pulse plating offers over conventional DC copper plating in high volume production applications for panels with aspect ratios of up to 12:1. These advantages are reduced plating time, increased throughput, and reduced plated copper thickness on the panel surface while meeting minimum in-hole copper thickness requirements.  

A New Method for Non-Destructive Characterization of Through Holes in Printed Circuit Boards

2018 ◽  
Vol 2018 (1) ◽  
pp. 000589-000595
Author(s):  
Sarah Czaplewski ◽  
Joe Doman ◽  
Joe Kuczynski
Keyword(s):  
Laser Scanning ◽  
Printed Circuit Boards ◽  
Critical Factor ◽  
Laser Scanning Microscopy ◽  
Circuit Boards ◽  
Casting Technique ◽  
Printed Circuit ◽  
Aspect Ratios ◽  
Plated Through Hole ◽  
Non Destructive

Abstract Plated through hole (PTH) quality, including plating roughness, is a critical factor in the manufacture of reliable printed circuit boards (PCBs). Currently, cross-sectioning is most commonly used to assess PTH roughness but sectioning is a destructive process and offers a limited view of the PTH. Therefore, a non-destructive casting method using a silicone elastomer was developed to evaluate PTH roughness. Castings were successfully created from PTHs with aspect ratios as high as 22:1 and the castings accurately replicated the microtopography of the plating. Laser scanning microscopy was used to quantitatively measure the surface roughness of the castings which was shown to correlate to current induced thermal cycling (CITC) coupon cycles to failure, a measurement of PTH reliability. Thus, the casting technique can be used to quickly assess PTH quality and its effect on reliability. In addition to plating roughness, it was demonstrated that the casting technique can be used to evaluate back drill quality, PTH diameter along the length of the barrel, as well as drill and desmear processes by casting non-plated through holes.

Ion Track Enabled High Aspect Ratio Flexible PCB Via Technology

2004 ◽  
Vol 833 ◽  
Author(s):  
Mikael Lindeberg ◽  
Hanna Yousef ◽  
Erik Öjefors ◽  
Anders Rydberg ◽  
Klas Hjort
Keyword(s):  
Cross Section ◽  
Printed Circuit Boards ◽  
Low Cost ◽  
Microwave Filters ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Aspect Ratios ◽  
Flexible Printed Circuit ◽  
Ion Track Technology ◽  
Resonance Microwave

ABSTRACTBy combining ion track technology with ordinary low-resolution printed circuitboard lithography it is possible at low cost to create high aspect ratios via connectors, as solid plugs or consisting of bundles of sub-micron connector wires at a small total cross-section.Ion track enabled microwave circuits in flexible printed circuit boards are suggested to be used in applications like inductors, ferromagnetic resonance microwave filters, circulators and magnetoresistive sensors. In this paper we demonstrate this technology with integrated printed circuitboard devices in two different flexible polyimide-based foils (Espandex and Kapton HN), using the ultra-high-density vias and the sub-micron wires.

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