Specification for conformal coating material for use on printed circuit assemblies

1980 ◽  
Keyword(s):  
Coating Material ◽  
Conformal Coating ◽  
Printed Circuit

scholarly journals Impact of Conformal Coating Material on the Long-Term Reliability of Ball Grid Array Solder Joints

2019 ◽  
Vol 38 ◽  
pp. 1138-1142
Author(s):  
Abid-Alrahman Fawzi Abbas ◽  
Christopher M. Greene ◽  
Krishnaswami Srihari ◽  
Daryl Santos ◽  
Ganesh Pandiarajan
Keyword(s):  
Solder Joints ◽  
Ball Grid Array ◽  
Coating Material ◽  
Conformal Coating

Arcing and Spacing Requirements for High Voltage Printed Circuit Boards

2015 ◽  
Author(s):  
Prabjit Singh
Keyword(s):  
High Voltage ◽  
Printed Circuit Boards ◽  
Power Supplies ◽  
Circuit Boards ◽  
High Voltage Power Supply ◽  
Conformal Coating ◽  
Printed Circuit ◽  
Electronic Hardware ◽  
Vacuum Test ◽  
Partial Vacuum

The electronic hardware miniaturization trend continues unabated. The reduced feature spacing expose the high voltage power supply circuits to arcing. The power MOSFET gate to drain and the drain to source lead gaps are narrow enough for zinc whiskers emanating from under the raised floor zinc plated tiles to arc across the MOSFET leads. Arcing can also occur because of paper cellulose fibers and dust in high relative humidity environments. The physics of arcing will be presented. Paschen’s law of arcing will be described; it will be shown how the law led to a novel way of testing power supplies for propensity to arcing. Examples of application of the test, called the partial vacuum test, to power supplies will be described. Testing the integrity of conformal coating is one useful application of the partial vacuum test. A novel zinc whisker spray test, developed to determine the spacing required to avoid arcing between features at high electric potential between them, will be described and its results will be presented that verify the UL feature spacing guidelines.

Contamination profile on typical printed circuit board assemblies vs soldering process

2014 ◽  
Vol 26 (4) ◽  
pp. 194-202 ◽  
Author(s):  
Helene Conseil ◽  
Morten Stendahl Jellesen ◽  
Rajan Ambat
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Content Type ◽  
Contamination Control ◽  
Conformal Coating ◽  
Printed Circuit ◽  
Soldering Process ◽  
Wave Soldering ◽  
Solder Flux ◽  
Set Up

Purpose – The purpose of this paper was to analyse typical printed circuit board assemblies (PCBAs) processed by reflow, wave or selective wave soldering for typical levels of process-related residues, resulting from a specific or combination of soldering processes. Typical solder flux residue distribution pattern, composition and concentration are profiled and reported. The effect of such contaminants on conformal coating was tested. Design/methodology/approach – Presence of localized flux residues was visualized using a commercial residue reliability assessment testing gel test and chemical structure was identified by Fourier transform infrared spectroscopy, while the concentration was measured using ion chromatography, and the electrical properties of the extracts were determined by measuring the leak current using a twin platinum electrode set-up. Localized extraction of residue was carried out using a commercial critical contamination control extraction system. Findings – Results clearly show that the amount and distribution of flux residues are a function of the soldering process, and the level can be reduced by an appropriate cleaning. Selective soldering process generates significantly higher levels of residues compared to the wave and reflow process. For conformal coated PCBAs, the contamination levels generated from the tested wave and selective soldering process are found to be enough to generate blisters under exposure to high humidity levels. Originality/value – Although it is generally known that different soldering processes can introduce contamination on the PCBA surface, compromising its cleanliness, no systematic work is reported investigating the relative levels of residue introduced by various soldering processes and its effect on corrosion reliability.

Impact of Conformal Coating Material on the Long-Term Reliability of Ball Grid Array Solder Joints

2020 ◽  
Vol 10 (11) ◽  
pp. 1861-1867
Author(s):  
Abid Alrahman Fawzi Abbas ◽  
Ganesh Pandiarajan ◽  
Satyanarayan Iyer ◽  
Christopher M. Greene ◽  
Daryl Santos ◽  
...  
Keyword(s):  
Solder Joints ◽  
Ball Grid Array ◽  
Coating Material ◽  
Conformal Coating

Characteristics of Radiated Emission from a Printed Circuit Board with a Slit

2012 ◽  
Vol 132 (6) ◽  
pp. 404-410 ◽  
Author(s):  
Kenichi Nakayama ◽  
Kenichi Kagoshima ◽  
Shigeki Takeda
Keyword(s):  
Printed Circuit Board ◽  
Circuit Board ◽  
Printed Circuit ◽  
Radiated Emission
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