Technical Library | 2017-12-07 10:35:50.0
Electronics manufacturers protect their circuit boards with conformal coatings. Conformal coatings serve as a barrier from environmental hazards and internal shorts, tin whiskers, and corrosion at the board level. Within conformal coatings different material chemistries specialize in shielding from an array of hazards and can be applied by multiple methods. The most common method is atomized spray which disperses the material into a fine mist. Alternatively, non-atomized coating controls the materials' dispense shape while maintaining the original liquid form. While some applications demand atomized spray and other scenarios overlap between atomized and non-atomized coating, this paper focuses on the circumstances where materials are ideally suited for non-atomized, selective coating.
Technical Library | 2013-07-03 10:31:54.0
It has been demonstrated in numerous pieces of work that stencil printing, one of the most complex PCB assembly processes, is one of the largest contributors to defects (Revelino et el). This complexity extends to prototype builds where a small number of boards need to be assembled quickly and reliably. Stencil printing is becoming increasingly challenging as packages shrink in size, increase in lead count and require closer lead spacing (finer pitch). Prototype SMT assembly can be further divided between industrial and commercial work and the DIYer, hobbyist or researcher groups. This second group is highly price sensitive when it comes to the materials used for the board assembly as their funds are sourced from personal or research monies as opposed to company funds. This has led to development of a lower cost SMT printing stencil made from plastic film as opposed to the more traditional stainless steel stencil used by industrial and commercial users.This study compares the performance of these two traditional materials and their respective impact on solder paste printing including efficiency and print quality.
Technical Library | 2024-09-02 17:01:54.0
A printed circuit board (PCB) is an integral component of any electronic product and is among the most challenging components to recycle. While PCB manufacturing processes undergo generations of innovation and advancement with 21st century technologies, the recycling of PCBs primarily employs 1920's shredding and separation technologies. There is a critical need for alternative PCB recycling routes to satisfy the increasing environmental demands. Previous work has developed an environmentally benign supercritical fluid process that successfully delaminated the PCB substrates and separated the PCB layers. While this work was successful in delamination of the PCB substrates, further understanding is needed to maximize the interactions between the supercritical fluid and PCB for an optimal processing scenario. As such, this research presents an exploratory study to further investigate the supercritical fluid PCB recycling process by using supercritical carbon dioxide and an additional amount of water to delaminate PCB substrates. The focus of this study is to test delamination success at low temperature and pressure supercritical conditions in comparison to the previous studies. Furthermore, material characterization methods, such as differential scanning calorimetry, dynamic mechanical analysis, and Fourier transform infrared spectroscopy, are included to study the delaminating mechanisms. Results from the recycling process testing showed that the PCB substrates delaminated easily and could be further separated into copper foils, glass fibers and polymers. Surprisingly, the material characterization suggested that there were no significant changes in glass transition temperature, crosslink density, and FTIR spectra of the PCBs before and after the supercritical fluid process.
Technical Library | 2013-04-25 11:42:01.0
Specification and control of surface roughness of copper conductors within printed circuit boards (PCBs) are increasingly desirable in multi-GHz designs as a part of signal-integrity failure analysis on high-speed PCBs. The development of a quality-assurance method to verify the use of foils with specified roughness grade during the PCB manufacturing process is also important... First published in the 2012 IPC APEX EXPO technical conference proceedings.
Technical Library | 2021-06-07 19:10:16.0
The aim of this study was to compare leaching characteristics of metals from printed circuit boards (PCBs), taken from waste electrical and electronic equipment in the presence and in the absence of the iron-oxidizing bacteria, Acidithiobacillus ferrooxidans. A. ferrooxidans not only increases the leached concentration of Cu from the PCBs, but also inhibits the components of the 0K medium and leached Cu from forming precipitates such as libethenite (Cu2(PO4)(OH)), thereby assisting Cu recovery from the PCBs. In addition, the leached concentration of Pb from PCBs decreased in the presence of A. ferrooxidans, due to Pb forming amorphous precipitates. It is expected that Pb is not highly toxic to A. ferrooxidans. Consequently, A. ferrooxidans can be used as a cost-effective and environmentally friendly way to leach out valuable metals from PCBs as low-grade urban ore.
Technical Library | 2023-09-08 06:33:02.0
Fume extraction starts with the capturing of airborne pollutants. In principle, the right collection strategy makes a decisive contribution to the quality of the extraction and filtration technology in air purification systems. Because the degree of collection is the basis for subsequent high-grade filtration, which ultimately results in the efficiency of an extraction system.
Technical Library | 2021-07-27 14:59:56.0
With increasing focus on reliability and miniaturized designs, Conductive Anodic Filament (CAF) as failure mechanism is gaining a lot of attention. Smaller geometries make the printed circuit board (PCB) susceptible to conductive anodic filament growth. Isola has carried out work to characterize the CAF susceptibility of various resin systems under different process and design conditions. Tests were carried out to determine the effect of various factors such as resin systems, glass finishes, voltage bias and hole and line spacings on the CAF resistance. This work was intended to provide information to the user on the suitability of various grades for specific end use applications. The focus of the work at Isola is to find the right combination of process and design conditions for improved CAF resistant products.
Technical Library | 2007-08-28 20:18:06.0
A conformal coating is defined as a thin polymeric material which covers the surface of an electronic assembly. These coatings are used to provide an electrically insulative and environmentally protective seal or cover to a completed printed circuit board (PCB).
Technical Library | 2011-01-20 19:50:30.0
This article introduces the technical development that went in to realizing an 80-layer ultra-multilayer printed circuit board, which meets the market demand for a "semiconductor test board supporting memory increases".
Technical Library | 2007-03-13 14:29:57.0
This article tells about the basics of manufacturing printed circuit boards including the terminology and the steps to processing a PCB.
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