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A thick film superconductor paste has been produced to determine the properties of granulated superconductor materials and to observe the percolation effect. The base of the paste was chosen to be of the BiSrCaCuO system because of its high Tc and advantageous current density properties. For contacts, a conventional Ag/Pt paste was used. The critical temperature was between 110 K and 115 K depending on the printed layer thickness. The critical current density was between 200 and 300 A/cm2. The R‐T and U‐l functions were measured with different parameters (Imeasuring. Bexternal. Number of layers, T). The measurement results confirmed the conducting mechanism theory in the material. A percolation structure model was built and is described. Finally, some fundamental advantages and problems of the process are discussed and the high‐frequency electric field sensor realised is described.

Fabrication and performance characteristics of a thick‐film laser power detector are presented. The new sensor combines the advantages of a circular resistor and highly sensitive NTC resistor paste. As a consequence of the layout, the sensitivity of this sensor depends slightly on the eccentricity and positioning of the laser beam. Therefore the measurement is simpler and the linearity and the reliability of detector are of a high standard.

The purpose of the present study was to review the thermo-mechanical challenges of reflowed lead-free solder joints in surface mount components (SMCs). The topics of the review include challenges in modelling of the reflow soldering process, optimization and the future challenges in the reflow soldering process. Besides, the numerical approach of lead-free solder reliability is also discussed.

Lead-free reflow soldering is one of the most significant processes in the development of surface mount technology, especially toward the miniaturization of the advanced SMCs package. The challenges lead to more complex thermal responses when the PCB assembly passes through the reflow oven. The virtual modelling tools facilitate the modelling and simulation of the lead-free reflow process, which provide more data and clear visualization on the particular process.

With the growing trend of computer power and software capability, the multidisciplinary simulation, such as the temperature and thermal stress of lead-free SMCs, under the influenced of a specific process atmosphere can be provided. A simulation modelling technique for the thermal response and flow field prediction of a reflow process is cost-effective and has greatly helped the engineer to eliminate guesswork. Besides, simulated-based optimization methods of the reflow process have gained popularity because of them being economical and have reduced time-consumption, and these provide more information compared to the experimental hardware. The advantages and disadvantages of the simulation modelling in the reflow soldering process are also briefly discussed.

This literature review provides the engineers and researchers with a profound understanding of the thermo-mechanical challenges of reflowed lead-free solder joints in SMCs and the challenges of simulation modelling in the reflow process.

The unique challenges in solder joint reliability, and direction of future research in reflow process were identified to clarify the solutions to solve lead-free reliability issues in the electronics manufacturing industry.

In microfluidic channel fabrication in low temperature co‐fired ceramics (LTCC), one of the biggest challenges is the elimination of channel deformation during lamination. The purpose of this paper is to describe the expected deformation of the substrate and the sacrificial layer (starch powder and 3D printed UV polymerized material) during the lamination process of microfluidic structure fabrication.

Uniaxial compression and Jenike shear test were used to obtain the mechanical parameters of starch sacrificial volume material (SVM). To determine the stress‐strain characteristics of LTCC a uniaxial compression experiment was conducted. The shape of the laminated LTCC containing embedded channel was modeled by finite element method using the mechanical parameters obtained by the measurements.

It was found that the choice of SVM plays an important role in channel deformation. A design rule is given considering the channel width and the choice of SVM based on the simulation results.

Until now the lamination step of LTCC technology was only optimized in an empirical way.

This study seeks to investigate the electrochemical migration (ECM) behaviour of printed circuit boards (PCBs) with Sn‐37Pb and Sn‐3.0Ag‐0.5Cu (wt.%) solders under various factors such as the distance between the electrodes and bias voltage.

This study investigated the ECM phenomena with different surface finishes of Sn‐37Pb and Sn‐3.0Ag‐0.5Cu solders using water drop (WD) and temperature and humidity bias (THB) tests. After the WD and THB tests, the dendrite phase was identified using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).

The ECM resistance of the conventional Sn‐37Pb alloy was lower than that of the Pb‐free Sn‐3.0Ag‐0.5Cu alloy. The dendrites grew at the cathode electrodes on the PCB and expanded to the anode electrode. The main elements in the dendrites on the Sn‐37Pb and Sn‐3.0Ag‐0.5Cu finished PCBs were tin and lead, respectively.

This study evaluates the ECM phenomena of representative solder alloys on PCBs.

This paper aims to present the results of investigations that show the influence of soldering process parameters on the optical and thermal parameters of power LEDs.

The power LEDs were soldered onto metal core printed circuit board (MCPCB) substrates in different soldering ovens: batch and tunnel types, characterized by different thermal profiles. Three types of solder pastes based on Sn99Ag0.3Cu0.7 with the addition of TiO₂ were used. The thermal and optical parameters of the diodes were measured using classical indirect electrical methods. The results of measurements obtained were compared and discussed.

It was shown that the type of oven and soldering thermal profile considerably influence the effectiveness of the removal of heat generated in the LEDs tested. This influence is characterized by thermal resistance changes. The differences between the values of this parameter can exceed 20%. This value also depends on the composition of the soldering paste. The differences between the diodes tested can exceed 15%. It was also shown that the luminous flux emitted by the diode depends on the soldering process used.

The results obtained could be useful for process design engineers for assembling power LEDs for MCPCBs and for designers of solid-state light sources.

This paper presents the results of investigations into the influence of the soldering profiles and soldering pastes used on the effectiveness of the removal of heat generated in power LEDs. It shows and discusses how the factors mentioned above influence the thermal resistance of the LEDs and optical parameters that characterize the light emitted.

The paper aims to present a comparative study of various thermocouple (TC) attaching methods for the proper measurement of soldering temperature profiling during vapour phase soldering (VPS). The heat transfer process during VPS is different from common methods, while the required heat for reflow is provided by the condensation. The condensate is a flowing layer on the board, where the dynamic behaviour also affects the local conditions on the surfaces. Temperature measurements based on TCs are also affected this way; it is important to investigate the process for deeper understanding.

Bare printed circuit boards (PCBs) were prepared for standard K-Type TCs attachment with industry standard materials: kapton polyimide tape, aluminium tape, SMD adhesive and high-temperature solder (HTS). Heating experiments were performed in a batch-type VPS oven with Galden LS240 fluid and fixed oven parameters.

According to the specific attachment requirements, HTS and Alu-tape are the suggested methods for better profiling reliability and repeatability. Alu-tape is the preferred all-around method, for fast, exchangeable, cheap, reliable and repeatable profiling in a VPS oven. It was presented that the heating factor (Q?) gives more reliable comparison overview; the time period-based comparisons may be affected by the thermal inertia, while heating factor also includes temperature conditions at the given time points.

The paper presents the reliability of the presented methods for VPS and present suggestions for the use of different TC ends and attaching materials during condensation heating of the PCBs. Also a new approach on profiling data evaluation based on the heating factor is presented and suggested for wider use.

In forecasting unknown quantities, risk and finance decision makers often rely on one or more biased experts, statistical specialists representing parties with an interest in the decision maker's final forecast. This problem arises in a variety of contexts, and the decision maker may represent a corporate enterprise, rating agency, government regulator, etc. The purpose of the paper is to assist decision makers, experts, and others to have a better understanding of the dynamics of the problem, and to adopt strategies and practices that enhance efficiency.

The problem is formulated as a two‐person, non‐cooperative Bayesian game with the decision maker and one expert as players, and perfect Bayesian equilibrium solutions are identified. Then the analysis is extended to variations of the game in which the expert's loss function is not common knowledge, and in which there are multiple experts.

In the struggle for information between the decision maker and the experts, the experts generally benefit from greater uncertainty about the parameters of the model. Thus, in attempting to elicit as much information as possible from the experts, the decision maker must strive to minimize all sources of uncertainty.

As in most Bayesian games, the analysis requires that a variety of process assumptions and model parameters be common knowledge. These conditions may be difficult to satisfy in real‐world applications.

The principal finding of the study is that there is truly a struggle for information between the decision maker and the experts. This generally encourages the experts to inject as much uncertainty as possible into the process. To counter this effect, the decision maker might: provide incentives for the experts to increase their sampling information; try to mitigate specific uncertainties regarding the model parameters; and try to increase the number of experts.

This is the first paper to apply the framework of signaling games to the problem of eliciting information from biased experts. It is of value to decision makers, experts, and economic researchers.

This paper aims to present a new method to calculate the appropriate volume of solder paste necessary for the pin-in-paste (PIP) technology. By the aid of this volume calculation, correction factors have been determined, which can be used to correct the solder fillet volume obtained by an explicit expression.

The method is based on calculating the optimal solder fillet shape and profile for through-hole (TH) components with given geometrical sizes. To calculate this optimal shape of the fillet, a script was written in Surface Evolver. The volume calculations were performed for different fillet radiuses (0.4-1.2 mm) and for different component lead geometries (circular and square cross-sections). Finally, the volume obtained by the Evolver calculations was divided by the volume obtained by an explicit expression, and correction factors were determined for the varying parameters.

The results showed that the explicit expression underestimates the fillet volume necessary for the PIP technology significantly (15-35 per cent). The correction factors for components with circular leads ranged between 1.4 and 1.59, whereas the correction factors for square leads ranged between 1.1 and 1.27. Applying this correction can aid in depositing the appropriate solder paste volume for TH components.

Determining the correct volume of solder paste necessary for the PIP technology is crucial to eliminate the common soldering failure of TH components (e.g. voiding or non-wetted solder pads). The explicit expression, which is widely used for volume calculation in this field, underestimates the necessary volume significantly. The new method can correct this estimation, and can aid the industry to approach zero-defect manufacturing in the PIP technology.

This paper aims to reveal the causes and find an efficient method to compensate the shrinkage to reduce failure costs. Reflow-induced printed circuit board (PCB) shrinkage is inspected in automotive electronics production environment. The shrinkage of two-sided, large PCBs results in printing offset errors and consequently soldering failures on smaller components during the reflow soldering of the second PCB side.

During the research, the investigations had to adapt to actual production in an electronics manufacturing plant. A measurement method was developed to approximate the overall shrinkage of the given product. With the shrinkage data, it is possible to perform an efficient compensation on the given stencil design in computer-aided manufacturing environment.

It was found that even with the investigated lower-quality PCB materials, the compensation on the stencil significantly reduces the quantity of failures, offering an efficient method to improve the yield of the production.

Research was oriented by the confines of production (fixed PCB sources, given PCB materials, reflow process and production line), where an immediate solution is needed. Future investigations should be focussed on the PCB parameters (different epoxy types, glass-fibre reinforcements, etc.).

The optimised production reduces overall failure costs. The stencil re-design and application is a fast and efficient way to immediately act against the shrinkage-induced failures. The method was successfully applied in automotive electronics production.

The paper presents a novel approach on solving an emerging problem during reflow.