Technical Library | 2021-08-11 00:55:44.0
In this article, the influence of shrinkage tensile stress in potting materials on the anti-overload performance of a circuit board was studied. Firstly, the phenomenon of shrinkage tensile stress in common potting materials was analyzed, and it was found that the commonly used potting adhesives displayed large shrinkage characteristics. Secondly, a small experiment was set up to verify that the shrinkage tensile stress of potting adhesives would lead to printed circuit board (PCB) deformation, and the shrinkage stress was contrary to the acceleration direction of overload. Thirdly, the influence of potting adhesives on the overload resistance of the PCB was analyzed.
Technical Library | 2019-03-06 21:26:14.0
Electronic assemblies use a large variety of polymer materials with different mechanical and thermal properties to provide protection in harsh usage environments. However, variability in the mechanical properties such as the coefficient of thermal expansion and elastic modulus effects the material selection process by introducing uncertainty to the long term impacts on the reliability of the electronics. Typically, the main reliability issue is solder joint fatigue which accounts for a large amount of failures in electronic components. Therefore, it is necessary to understand the effect of polymer encapsulations (coatings, pottings and underfills) on the solder joints when predicting reliability.This paper presents the construction and validation of a thermo-mechanical tensile fatigue specimen. The thermal cycling range was matched with potting expansion properties in order to vary the magnitude of tensile stress imposed on solder joints
Technical Library | 2022-09-25 20:18:33.0
Printed circuit board (PCB) bending and/or flexing is an unavoidable phenomenon that is known to exist and is easily encountered during electronic board assembly processes. PCB bending and/or flexing is the fundamental source of tensile stress induced on the electronic components on the board assembly. For more brittle components, like ceramic-based electronic components, micro-cracks can be induced, which can eventually lead to a fatal failure of the components. For this reason, many standards organizations throughout the world specify the methods under which electronic board assemblies must be tested to ensure their robustness, sometimes as a pre-condition to more rigorous environmental tests such as thermal cycling or thermal shock.
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