Effect of High-Humidity Testing on Material Parameters of Flexible Printed Circuit Board Materials

Lahokallio, Sanna; Saarinen, Kari; Frisk, Laura

doi:10.1007/s11664-013-2652-6

Cited by 11 publications

(4 citation statements)

References 24 publications

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“…In Ref. 40, no variation of the elastic moduli was observed for PI films subjected to high humidity environments (85°C and 85% RH) after 6000 h of aging, but the tests were performed on relatively thick (50 μm) PI films.…”

Section: Resultsmentioning

confidence: 99%

Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method

Montinaro,

Lo Cicero,

D’Anca

et al. 2023

J. Astron. Telesc. Instrum. Syst.

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The x-ray detectors on board astrophysics space missions require optical blocking filters that are highly transparent to x-rays. The filter design typically consists of a polymeric film that is a few tens of nanometers thick coated with aluminium. Due to the large size of the filter membrane (from a few tens to a few hundred square centimeters) and the extreme aspect ratio, together with severe loading conditions during launch and different stoichiometries of the polymer that could change its mechanical properties, a characterization study of the employed material is needed. The plane strain bulge test is a well-accepted methodology for the mechanical testing of structures that are less than a micrometer thick, and especially for freestanding membranes. Unfortunately, testing such ultra-thin films is not a simple task due to residual stress and experimental uncertainty at very low pressure. In this work, the elastic properties of an extremely thin (between 45 and 415 nm) membrane made of bare polyimide and coated with aluminium were derived through adopting a combined experimental-numerical methodology based on the bulge test and numerical simulations.

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Section: Resultsmentioning

confidence: 99%

Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method

Montinaro,

Lo Cicero,

D’Anca

et al. 2023

J. Astron. Telesc. Instrum. Syst.

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“…Experiments reveal that the water/moisture absorption can be reduced from 4.87% to 1.15% and the electrical properties of the PCB improved by means of chemical treatment [28,29]. However, it has also been reported that these alternate materials are not a wise choice, since they tend to absorb moisture which reduces their dielectric integrity [30] and interferes with the performance of electronic devices [30].…”

Section: Impact Of Water Ingress Of Moisture On Pcbmentioning

confidence: 99%

Influence of Water Ingress on Surface Discharges Occurring on the Silicone Gel Encapsulated Printed Circuit Boards Developed for Deep-Sea Applications

Arumugam

Haba

et al. 2023

Energies

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This paper discusses the influence of water ingress on the electrical discharges that arise on the surface of printed circuit boards that are developed for deep sea applications. The primary concern is the electrical discharges arising on the surface of the PCB bridging localized spots/areas between conductive traces, high voltage terminal, mounting hole options, and so on. The current literature focuses on electrical discharges arising on the surface of PCB at low-pressure environments emulating aircraft and space applications. Extending the same approach to deep-sea environments is not feasible since the pressure is very high and the temperatures are very low. In all, a meager attempt has been made to investigate the possible application of such gel-encapsulated PCBs in adverse high-pressure, salt/sea water, low-temperature, deep-sea environments. This experimental study focuses on studying the influence of deionized and sea water on electrical discharges arising on the surface, between conductive tracks of PCB. A group of PCBs with different gaps between the conductive tracks was produced and immersed in deionized and seawater for a specific duration at standard pressure. Afterward, the discharge characteristics were measured the using partial discharge (PD) test method and the respective phase-resolved PD pattern was studied and analyzed. Pertinent experiments revealed that the PD process and eventual failure manifests as a typical and substantial pattern. The apparent charge measured during the PD inception and near-by failure condition, influenced by deionized and seawater, reveals a regular trend. Naturally, a simple observation of the PD pattern might help to identify the intricacy and to initiate a preventive measure well before the complete system suffers a premature failure. Also, based on these results, making slight structural modifications on the PCB at crucial locations might help in retaining the dielectric integrity of the material.

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“…Moreover, the PCB substrate can be fragile and its performance may depend on humidity and other environmental conditions. Lahokallio et al (2013) presented the influence of humidity and temperature onto the mechanical and electrical properties of the three popular PCB materials. Presented results of aging process proved, that each of them may change their technical parameters in time and it could be difficult to predict this process because of many factors.…”

Section: Introductionmentioning

confidence: 99%

Highly accurate and numerically stable computations of double-layer coaxial waveguides

Kubiczek

Kampik

2019

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Purpose The purpose of this study is to develop and investigate a fast and accurate algorithm for the modeling of characteristic impedance of double-layer coaxial waveguides. Design/methodology/approach This paper presents the newly developed numerically stable analytical formula for calculation of the characteristic impedance of double-layer coaxial conductor and its elements such as resistance, inductance, capacitance and conductance per unit length. The formula contains modified scaled Bessel functions. The results of the developed analytical formula were compared with results obtained from the axis-symmetric 2D and 3D finite element method (FEM) simulations, using three different solvers. Findings The proposed method shows a good agreement between results obtained with the new fast and stable analytical model and particular FEM models, selected depending on frequency range. The relative difference between characteristic impedance calculated using the new analytical method and obtained from chosen FEM method for discussed frequency range is less than 0.1 per cent which proves the correctness of the new analytical formula. Noteworthy is the fact that the relative difference of the resistance computed using the developed analytical method and obtained with Maxwell FEM solver for the frequency in range from 1 Hz to 10 MHz is less than 0.01 per cent. The presented work shows that when the calculations are performed over wide frequency range, it is necessary to use more than one solver, especially when the wavelength is comparable with dimensions of the conductor. The computation time of the new analytical model is much shorter than the computation time of FEM. Originality/value An efficient, numerically stable algorithm for computation of characteristic impedance of a double-layer coaxial conductor (waveguide).

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Effect of High-Humidity Testing on Material Parameters of Flexible Printed Circuit Board Materials

Cited by 11 publications

References 24 publications

Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method

Elastic characterization of nanometer-thick polymeric film for astrophysics application with an experimental-numerical method

Influence of Water Ingress on Surface Discharges Occurring on the Silicone Gel Encapsulated Printed Circuit Boards Developed for Deep-Sea Applications

Highly accurate and numerically stable computations of double-layer coaxial waveguides

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