Mechanical and thermal reliability of conductive circuits inkjet printed on flexible substrates

Circuit World ◽  
2017 ◽  
Vol 43 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Aneta Arazna ◽  
Kamil Janeczek ◽  
Konrad Futera
Keyword(s):  
Thermal Annealing ◽  
Inkjet Printing ◽  
Printed Circuit Boards ◽  
Flexible Substrate ◽  
Flexible Substrates ◽  
Circuit Boards ◽  
Electronic Circuits ◽  
Content Type ◽  
Printed Circuit ◽  
Kapton Foil

Purpose This paper aims to present the results of investigations of inkjet-printed electronic circuits fabricated on a flexible substrate (KAPTON foil) using silver nanoparticles ink. Design/methodology/approach Fully inkjet-printed conductive circuit tracks were printed on a flexible, transparent KAPTON foil, using a commercial 40LT-15 C nanosilver ink as well as a PixDro LP50 inkjet printer with KonicaMinnolta 512 printhead. After cure, electrical properties by resistance measurements and printing quality by optical and SEM microscopic observation of conductive tracks were examined. Afterwards, the tested samples were annealed for 1, 2 and 3 h at 150°C or subjected to cycling bending. Findings It was found that silver nanoparticles ink could be used for the preparation of electronic circuits using the inkjet printing technique. The obtained patterns had appropriate mapping and good quality. It was also noticed that thermal annealing caused a decrease in resistivity values of the tested lines irrespective of their width. Approximately 34 per cent decrease was achieved in the values of resistivity of all the tested lines after the first hour of thermal annealing. After the second hour, the values of resistivity decreased by another 50 per cent. There were no visible changes in resistivity values after 1,000 cycles of bending. Originality/value In this paper, the results of thermal annealing and bending tests of inkjet-printed silver nanoparticle conductive tracks on flexible substrate were presented. That is very important information for producing printed circuit boards using ecological, rapid and low-cost inkjet printing techniques, particularly during the production of printed circuit boards on flexible substrates working in different conditions of mechanical and thermal stresses.

scholarly journals Stretchable and Washable Electronics for Embedding in Textiles

2010 ◽  
Vol 1271 ◽  
Author(s):  
Thomas Vervust ◽  
Frederick Bossuyt ◽  
Fabrice Axisa ◽  
Jan Vanfleteren
Keyword(s):  
Printed Circuit Boards ◽  
Electronic System ◽  
Flexible Substrates ◽  
Circuit Boards ◽  
Electronic Circuits ◽  
Testing Methods ◽  
Printed Circuit ◽  
Wearable Systems ◽  
Led Matrix ◽  
User Comfort

AbstractElectronics in “wearable systems” or “smart textiles” are nowadays mainly realized on traditional interconnection substrates, like rigid Printed Circuit Boards (PCB) or mechanically flexible substrates. The electronic modules are detachable to allow cleaning and washing of the textile. In order to achieve a higher degree of integration and user comfort, IMEC-UGent/CMST developed a technology for flexible and stretchable electronic circuits. The electronic system is completely embedded in an elastomer material like PDMS (silicone), resulting in soft and stretchable electronic modules. The technology uses standard packaged components (IC's) and meander shaped copper tracks, so that stretchable systems with complex functionality can be achieved. Testing methods for washability were selected and developed. First tests are showing promising results, leveling the path to washable electronics in textiles. In order to show the possibilities of the technology in the field of textile applications a 7x8 single color stretchable LED-matrix was designed and integrated in textile. This LED-matrix can be applied for example in wearable signage applications.

New technologies of multi-layered printed circuit boards, intended of rapid-design electronic modules

Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 121-124
Author(s):  
Wojciech Stęplewski ◽  
Mateusz Mroczkowski ◽  
Radoslav Darakchiev ◽  
Konrad Futera ◽  
Grażyna Kozioł
Keyword(s):  
Printed Circuit Boards ◽  
New Technologies ◽  
Circuit Board ◽  
Circuit Boards ◽  
Content Type ◽  
Signal Distribution ◽  
Printed Circuit ◽  
Rapid Design ◽  
Small Pitch ◽  
Signal Path

Purpose – The purpose of this study was the use of embedded components technology and innovative concepts of the printed circuit board (PCB) for electronic modules containing field-programmable gate array (FPGA) devices with a large number of pins (e.g. Virtex 6, FF1156/RF1156 package, 1,156 pins). Design/methodology/approach – In the multi-layered boards, embedded passive components that support FPGA device input/output (I/O), such as blocking capacitors and pull-up resistors, were used. These modules can be used in rapid design of electronic devices. In the study, the MC16T FaradFlex material was used for the inner capacitive layer. The Ohmega-Ply RCM 25 Ω/sq material was used to manufacture pull-up resistors for high-frequency pins. The embedded components have been connected to pins of the FPGA component by using plated-through holes for capacitors and blind vias for resistors. Also, a technique for a board-to-board joining, by using castellated terminations, is described. Findings – The fully functional modules for assembly of the FPGA were manufactured. Achieved resistance of embedded micro resistors, as small as the smallest currently used surface-mount device components (01005), was below required tolerance of 10 per cent. Obtained tolerance of capacitors was less than 3 per cent. Use of embedded components allowed to replace the pull-up resistors and blocking capacitors and shortens the signal path from the I/O of the FPGA. Correct connection to the castellated terminations with a very small pitch was also obtained. This allows in further planned studies to create a full signal distribution system from the FPGA without the use of unreliable plug connectors in aviation and space technology. Originality/value – This study developed and manufactured several innovative concepts of signal distribution from printed circuit boards. The signal distribution solutions were integrated with embedded components, which allowed for significant reduction in the signal path. This study allows us to build the target object that is the module for rapid design of the FPGA device. Usage of a pre-designed module would lessen the time needed to develop a FPGA-based device, as a significant part of the necessary work (mainly designing the signal and power fan-out) will already be done during the module development.

Influence of the cavities on the PCB mechanical properties

Circuit World ◽  
2015 ◽  
Vol 41 (2) ◽  
pp. 76-79
Author(s):  
Boleslav Psota ◽  
Alexandr Otáhal ◽  
Ivan Szendiuch
Keyword(s):  
Mechanical Properties ◽  
Resonant Frequency ◽  
Design Methodology ◽  
Printed Circuit Boards ◽  
Measured Data ◽  
Circuit Boards ◽  
Frequency Range ◽  
Content Type ◽  
Printed Circuit ◽  
Acceleration Amplitude

Purpose – The main aim of this paper is to investigate the influence of the cavity coverage on the printed circuit boards (PCB) to the resonant frequency, acceleration and displacement. Design/methodology/approach – Tests were realized on four PCBs with different cavity areas. Frequency range of tests was between 10 and 2,000 Hz with 0.3 g acceleration amplitude. In addition, more simulations were performed to check different setups of the boards. Findings – From the calculated and measured data, it is clear that with the larger cavity area the resonance frequency drops. In case a greater number of components placed in cavities are needed on board, it is appropriate to use multiple smaller cavities than the bigger ones. Originality/value – Results in this paper could be very useful for PCB manufacturers and designers during designing of the new PCBs with cavities for dipped components.

Identification of printed circuit boards mechanical properties using response surface methods

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammad Gharaibeh
Keyword(s):  
Finite Element ◽  
Response Surface ◽  
Material Properties ◽  
Printed Circuit Boards ◽  
Dynamic Testing ◽  
Mode Shapes ◽  
Fe Model ◽  
Circuit Boards ◽  
Content Type ◽  
Printed Circuit

Purpose This study aims to discuss the determination of the unknown in-plane mechanical material properties of printed circuit boards (PCBs) by correlating the results from dynamic testing and finite element (FE) models using the response surface method (RSM). Design/methodology/approach The first 10 resonant frequencies and vibratory mode shapes are measured using modal analysis with hammer testing experiment, and hence, systematically compared with finite element analysis (FEA) results. The RSM is consequently used to minimize the cumulative error between dynamic testing and FEA results by continuously modifying the FE model, to acquire material properties of PCBs. Findings Great agreement is shown when comparing FEA to measurements, the optimum in-plane material properties were identified, and hence, verified. Originality/value This paper used FEA and RSMs along with modal measurements to obtain in-plane material properties of PCBs. The methodology presented here can be easily generalized and repeated for different board designs and configurations.

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.

Assessment of stability and reliability of embedded components in printed circuit boards

Circuit World ◽  
2017 ◽  
Vol 43 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Wojciech Steplewski ◽  
Andrzej Dziedzic ◽  
Janusz Borecki ◽  
Tomasz Serzysko
Keyword(s):  
Thin Film ◽  
Thick Film ◽  
Environmental Conditions ◽  
Printed Circuit Boards ◽  
Thermal Exposure ◽  
Circuit Boards ◽  
Content Type ◽  
Embedded Capacitors ◽  
Printed Circuit ◽  
Thin Film Resistors

Purpose The purpose of this paper is to investigate the basic functional parameters of passive embedded components in printed circuit boards (PCBs) under environmental exposures such as thermal-humidity and thermal exposure. Design/methodology/approach The investigations were based on the thin-film resistors made of NiP alloy, thick-film resistors made of carbon or carbon–silver inks, embedded capacitors made of FaradFlex materials and embedded inductor made in various configurations. The capacitors and thin- and thick-film resistors were tested in the climatic chamber in conditions of thermal-humidity exposure at 85°C and 85 per cent RH for 500 h. The embedded inductors were tested in two different environmental conditions: thermal-humidity exposure at 60°C and 95 per cent RH, and thermal exposure at 150°C and additionally at the temperature in the range of +25°C to +150°C. Findings Studies show that in the case of embedded capacitors, the changes caused by exposure to thermal-humidity are durable and lead to the capacity increase. The embedded thin-film resistors behave in the same manner, whereas the thick-film resistors were the least resistant to the conditions of exposure. Most of the polymer thick-film resistors have been damaged. The changes of coils' properties during aging are small, and what is most important is that, after some time of exposure, their parameters stabilize at a particular level. The changes resulting from the increase in temperature are typically related to the change of material resistance (Cu) of which coils are made, and as such, they cannot be avoided but they can be predicted. Research limitations/implications The realized studies allowed determination of the properties of the embedded passive elements with respect to specific environmental exposures. The studies show that embedded resistors can be used interchangeably with chip passive elements. It allows saving the area on the surface of PCB, occupied by these passive elements, for assembly of active elements integrated circuits (ICs) and thus enabling the miniaturization of electronic devices. Originality/value The knowledge about the behavior of the operating parameters of embedded components, considering the environmental conditions, allows for development of more complex systems with integrated PCBs.

Influence of thermal cycling on reliability of solder joints executed on long and metal core PCBs

2015 ◽  
Vol 27 (3) ◽  
pp. 120-124 ◽  
Author(s):  
Janusz Sitek ◽  
Aneta Araźna ◽  
Kamil Janeczek ◽  
Wojciech Stęplewski ◽  
Krzysztof Lipiec ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Circuit Board ◽  
Circuit Boards ◽  
Thermal Cycles ◽  
Metal Core ◽  
Content Type ◽  
Printed Circuit ◽  
Reliability Of Solder Joints

Purpose – The purpose of this paper is to evaluate the reliability of solder joints made on long FR-4 and metal core printed circuit boards using the accelerated thermal cycling. Design/methodology/approach – Solder joints of diodes and resistors samples made on long FR-4 and aluminum (Al) core printed circuit boards were examined. Two kinds of solder pastes were used for the samples preparation. All samples were subjected to temperature aging cycles (−40°C – 3 hours/+85°C – 3 hours). Solder joints resistance, X-Ray inspection and metallographic cross-sections for samples as received and after 100, 500 and 1,000 hours of thermal cycles were utilized for solder joints assessment. Findings – It was stated that 1,000 hours of thermal cycles were enough to show reliability problems in solder joints on long and/or AL core printed circuit board assembly (PCBA). The solder joints of R1206 components were the most sensitive reliability elements. The solder joints of LED diodes are more reliable than solder joints of R1206 resistors. Solder joints made on FR-4 substrate were about two times more reliable than ones on AL core substrate. Cracks in solder joints were the visible reason of solder joints failures. Originality/value – The influence of thermal cycles on the reliability of solder joints on long, FR-4 and metal core printed circuit boards were presented. Findings from this paper can be used for planning of reliability trials during validation of reflow processes of products containing long or long metal core printed circuit boards (PCBs).

Local damage simulations of printed circuit boards based on in‐plane cohesive zone parameters

Circuit World ◽  
2013 ◽  
Vol 39 (2) ◽  
pp. 60-66 ◽  
Author(s):  
Peter Filipp Fuchs ◽  
Klaus Fellner ◽  
Gerald Pinter
Keyword(s):  
Finite Element ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Cohesive Zone ◽  
Printed Circuit Boards ◽  
Circuit Board ◽  
Circuit Boards ◽  
Content Type ◽  
Printed Circuit

PurposeThe purpose of this paper is to analyse, in a finite element simulation, the failure of a multilayer printed circuit board (PCB), exposed to an impact load, to better evaluate the reliability and lifetime. Thereby the focus was set on failures in the outermost epoxy layer.Design/methodology/approachThe fracture behaviour of the affected material was characterized. The parameters of a cohesive zone law were determined by performing a double cantilever beam test and a corresponding simulation. The cohesive zone law was used in an enriched finite element local simulation model to predict the crack initiation and crack propagation. Using the determined location of the initial crack, the energy release rate at the crack tip was calculated, allowing an evaluation of the local loading situation.FindingsA good concurrence between the simulated and the experimentally observed failure pattern was observed. Calculating the energy release rate of two example PCBs, the significant influence of the chosen type on the local failure behaviour was proven.Originality/valueThe work presented in this paper allows for the simulation and evaluation of failure in the outermost epoxy layers of printed circuit boards due to impact loads.

Defect detection of bare printed circuit boards based on gradient direction information entropy and uniform local binary patterns

Circuit World ◽  
2017 ◽  
Vol 43 (4) ◽  
pp. 145-151 ◽  
Author(s):  
Yunfeng Li ◽  
Shengyang Li
Keyword(s):  
Information Entropy ◽  
Printed Circuit Boards ◽  
Feature Vector ◽  
Local Binary Patterns ◽  
Significant Degree ◽  
Circuit Boards ◽  
Content Type ◽  
Printed Circuit ◽  
Gradient Direction ◽  
Direction Information

Purpose The purpose of this paper is to propose a defect detection method of bare printed circuit boards (PCB) with high accuracy. Design/methodology/approach First, bilateral filtering of the PCB image was performed in the uniform color space, and the copper-clad areas were segmented according to the color difference among different areas. Then, according to the chaotic characteristics of the spatial distribution and the gradient direction of the edge pixels on the boundary of the defective areas, the feature vector, which evaluates quantitatively the significant degree of the defect characteristics by using the gradient direction information entropy and the uniform local binary patterns, was constructed. Finally, support vector machine classifier was used for the identification and localization of the PCB defects. Findings Experimental results show that the proposed algorithm can accurately detect typical defects of the bare PCB, such as short circuit, open circuit, scratches and voids. Originality/value Considering the limitations of describing all kinds of defects on bare PCB by using single kind of feature, the gradient direction information entropy and the local binary patterns were fused to build a feature vector, which evaluates quantitatively the significant degree of the defect features.

Reactance components embedded in printed circuit boards

Circuit World ◽  
2015 ◽  
Vol 41 (3) ◽  
pp. 125-132 ◽  
Author(s):  
Wojciech Stęplewski ◽  
Andrzej Dziedzic ◽  
Adam Kłossowicz ◽  
Paweł Winiarski ◽  
Janusz Borecki ◽  
...  
Keyword(s):  
Loss Tangent ◽  
Radio Frequency Identification ◽  
Printed Circuit Boards ◽  
Elevated Temperatures ◽  
Magnetic Core ◽  
Circuit Boards ◽  
Magnetic Composites ◽  
Content Type ◽  
Embedded Capacitors ◽  
Printed Circuit

Purpose – This paper aims to report the investigations of capacitors and inductors embedded into printed circuit boards (PCBs) designed in various layouts. Design/methodology/approach – The research were focused on the components embedded into four-layer PCBs with different structures of the inner layers. Three special capacitive laminates for manufacturing of thin-film embedded capacitors and several types of coils in the form of a spiral, meander and solenoid are described. In addition, a part of the spiral-type coils was formed with an aperture in the center in which the magnetic core, made of soft magnetic composites’ material was placed to increase the coil inductance. Findings – Various constructions of embedded capacitors and coils were designed and manufactured. Capacitance and loss tangent of capacitors to determine the repeatability of the production process were determined. Capacitor’s long-term stability analysis was performed by exposing test samples to elevated temperatures (70, 100 or 130°C), realized with the aid of heating plate, for at least 160 h. The temperature characteristics for the capacitance and loss tangent from 15 to 100°C were determined. Also the induction of different designs and layouts coils was determined. Originality/value – The wide parameters’ characterization of capacitors and coils embedded into PCBs allow the analysis of their properties with regard to their practical application. The promising results of the realized measurements show that the capacitors and induction coils with studied structures can be widely used in the construction of embedded circuits into PCBs (e.g. filters, radio frequency identification systems and generators).

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