Surface Mount Research Articles

A Method for Deembedding the Mounting Pad and Via-Hole Effect in a Test Fixture for Accurate Impedance Measurement of the Surface Mount Device Component

A Method for Deembedding the Mounting Pad and Via-Hole Effect in a Test Fixture for Accurate Impedance Measurement of the Surface Mount Device Component

Controlling PMSG Wind Turbine Connected to Three Level Neutral Point Clamped Inverter Based on MPC

Wind energy generation systems are facing increasing importance in terms of harmonic distortion control and power quality standards. In recent years, variable speed has also risen rapidly due to advancements in power electronics. The three key elements of a wind power conversion system (WECS) are electrical generators, machine-side converters, and grid-side converters. It should be noted that the permanent magnet synchronous generator is one of the most often used types of electrical generators due to its special qualities. When wind energy is converted to the proper electrical power, it may be injected into the utility grid using either synchronous generators or grid-side converters. Therefore, an investigation of several topologies and control strategies is required to determine which is the best for the machine-side converter. The use of model predictive control (MPC) for a surface mount permanent magnet synchronous machine wind turbine is the main topic of this work. The machine's electrical model is the one that was utilized. The power converters are selected considering the intricate and highly nonlinear aerodynamic system of the wind turbines. MPC is a promising control technique despite being a relatively recent application in power electronics. In addition, MATLAB and Simulink are used to build the MPC code and offer a simplified model of the turbine.

A matrix eddy current transducer using surface mount inductors

The paper reports the results of testing the by us developed detachable matrix eddy current transducer designed to detect discontinuities on the surface of thin (tens of micrometers) inspected conductive objects, in particular, electrically conductive coatings of aircraft fuel tanks. The transducer can be useful for other applications, e.g. magnetic tomography. The device consists of 32 miniature inductors series-produced by the electronic industry and allowing you to cover an 80 mm wide band with a 2.5 mm wide test path. The use of inductance coils as magnetic receivers is due to the small thickness of the coatings to be tested. With this thickness, testing is effective only at an operating frequency of hundreds of kilohertz. Otherwise, the sounding magnetic field will not be reflected from the item under inspection. At these frequencies, modern microelectronic magnetic field sensors are inoperable. Scanning was carried out at an operating frequency of about 100 kHz. The scan results were displayed on the monitor of the personal computer. By selecting the operating frequency, the information content of the examination can be increased. The transducer detects the pattern of the copper foil of glass textolite both on the foil side and on the reverse side when the material thickness is 1.5 mm. The foil pattern is also detected through an aluminum foil gasket with a thickness of more than 10 μm. Steel plate surface discontinuities have also been detected, and this can be of interest for in-tube flaw detection. Cheap serial inductors designed for surface mounting take up a minimum of space on the printed circuit board and provide higher inspection resolution compared to coils obtained by printing. The scanning step (2.5 mm) achieved in this device is unique to matrix eddy current transducers. The study demonstrates the practicality and efficiency of using serial miniature inductors in eddy current testing.

Low-Cost Optical pH Sensor with a Polyaniline (PANI)-Sensitive Layer Based on Commercial Off-the-Shelf (COTS) Components.

In this paper, we presented a novel, compact, conceptually simple, and fully functional low-cost prototype of a pH sensor with a PANI thin film as a sensing layer. The PANI deposition process is truly low-cost; it performs from the liquid phase, does not required any specialized equipment, and comprises few processing steps. The resulting PANI layer has excellent stability, resistance to solvents, and bio- and chemical compatibility. The pH sensor's sensing part includes only a few components such as a red-light-emitting diode (LED) as a light source, and a corresponding photodiode (PD) as a detector. Unlike other PANI-based sensors, it requires no sophisticated and expensive techniques and components such lasers to excite the PANI or spectrometry to identify the PANI color change induced by pH variation. The pH sensor is sensitive in the broad pH range of 3 to 9, which is useful for numerous practical applications. The sensor requires a tiny volume of the test specimen, as little as 55 µL. We developed a fully integrated packaging solution for the pH sensor that comprises a limited number of components. The pH sensor comprises exclusively commercial off-the-shelf (COTS) components and standard printed circuit boards. The pH sensor is assembled using standard surface mounting technology (SMT).

Effect of Sn Plating Thickness on Wettability, Solderability, and Electrical Connections of Electronic Lead Connectors for Surface Mount Technology Applications

The wettability of solder is important to achieve good solderability between the electronic component and printed circuit board (PCB). Tin (Sn) plating is widely used to promote the wettability of the solder on the substrates. However, an adequate amount of Sn plating thickness must be taken into consideration to acquire good wettability and solderability. Thus, this study investigates the Sn plating thickness of the electronic lead connector and their effect on the wettability and electrical connection. Two types of Sn plating thicknesses, ~3 μm, and 5 μm were applied on the electronic lead connector surface. It was found that the thin Sn plating thickness of ~3 μm has shown failure in electrical connections and lack of solder joint wettability and solderability properties. A thicker Sn plating thickness of 5 μm, has shown better wettability and solderability properties. In addition, the electrical connections also passed which implies that the thicker Sn plating thickness provides good solder joint establishment leading to good electrical connections. It is also observed that the better wettability of solder has been achieved for thicker Sn plating thickness. The finding from the field emission scanning electron microscope (FESEM) shows that the intermetallic compound (IMC) layer growth in the lead connector surface is regarded as abnormal for thin Sn plating thickness (~3 μm), in which the IMC layer was consumed and penetrating up to the surface of Sn-coating. This has led to poor solderability of the thin Sn plating with the solder to establish solder joint. The findings from this study have shed some light upon a better understanding of the importance of considering the adequate amount of Sn coating thickness to avoid IMC consumption at the Sn plating, better wettability properties, solderability, and solder joint quality for surface mount technology (SMT) especially for electronic lead connector applications.

Glass Devices for Next-Generation Packaging and RF Signal Conditioning

The push for higher communications frequencies, greater system integration, and smaller space imparts many unique challenges on RF and packaging engineers in the development of next generation cellular products for 5G, WiFi 6, Military, and other applications. Traditional materials, such as LTCC, organic laminates, and silicon face major limitations to dramatically improve system size, weight, and performance (SWAP). Photosensitive Glass-Ceramics (PSG) have gained a lot of attention as a next generation RF and RF packaging substrate for their ability to simultaneously solve these two important challenges. In this paper the authors will present on our work using PSG for RF and RF packaging solutions. We will share (1) the advantages of using PSG for advanced RF packages, and (2) our work demonstrating glass as an RF substrate integrating discrete components and embedded die for passive RF filters, and (3) our work towards building vertically stacked glass packages for advanced RF systems-in-package (SiP). The described work presents a manufacturing platform for the production of vertically stacked glass substrates with integrated high Quality Factor passive devices, such as inductors and capacitors, and heterogeneously integrated surface mount devices for advanced RF systems-in-package. The presented material demonstrates a production and assembly process for the manufacturing of advanced systems. In this paper, we present design, production, assembly considerations that impact size, weight, and performance (SWAP) metrics for a variety of product definitions and multiple simulation vs. product testing to demonstrate a reliable design to product flow.

An efficient microwave outphasing transmitter based on class-E power amplifiers

This article presents two alternative topologies combining lumped and distributed elements for designing class-E power amplifiers (PAs) for the 3.5 GHz frequency band, that differ in their approach to terminating the second harmonic. The first design employs a transmission line with a capacitor to create a short-circuit, while the second design uses a simple stub. The first design outperforms the second one in terms of efficiency enhancement. Accordingly, an outphasing transmitter based on a surface mount hybrid coupler combiner is designed using the first topology, achieving peak value results of 78% drain efficiency and 44.3 dBm output power. At a 6 dB back-off point, the simulation results show that the proposed architecture achieves 67.6% drain efficiency.

Terminals and Connector Inspection Innovation using Machine Vision

Customer demands for product quality that are increasingly complex and require more accurate inspection are not sufficient if done manually due to high costs and different operator precision. To solve this problem, automatic vision inspection was created to check the product quality of terminal-type electronic components. Machine Vision is robust equipment for examining electrical components, agroindustry, surface mounting technology industry, plastic industry, and glass industry. In this research, the design and application of machine vision are used to inspect terminals and connectors, supporting automotive and electrical equipment components. Machine vision checks three quality functions, namely structural quality, surface quality, and dimensional quality. Optimization of image capture using backlighting and darkfield lighting. Implementing machine vision is carried out by verifying image retrieval's stability using a gage study with the results that there is no measurement bias.

10 GHz MONOLITHIC FILTER BASED ON STRIPLINE RESONATORS WITH SPLIT CONDUCTOR

The monolithic design of the compact bandpass filter X-band is made on technology of multilayered printed circuit boards. A quarter-wave stripline resonators of the filter have two conductors divided by the layer prepreg having low parameters which is bonding together a design. This eliminates influence of prepreg on the characteristics of the devices, ensuring good repeatability of filters in mass production. For increase the high-frequency stopband of filter, one of the conductors of each resonator is cut in half by a transverse slit. The constructive sizes of the device were obtained by parametric synthesis using the electrodynamic analysis of its 3D model. The experimental data of five-order filter are in good agreement with the electromagnetic simulation of filters 3D model. An experimental device has a central frequency of the passband of 10 GHz and fractional bandwidth of 5.7%, its dimensions and weight are 18.0 × 5.4 × 2.1 mm and 0.5 g. The important advantage of the developed design is the possibility of its installation on the board using the surface mounting method.

An improved spider monkey optimization algorithm for multi-objective planning and scheduling problems of PCB assembly line

In recent years, the demand for printed circuit boards (PCBs) with various electronic components has tremendously increased due to high customization in smart electronic devices. To meet the market competition, efficient and realistic decisions with optimum planning and scheduling are required to enhance the productivity of PCB industries. Processing time of surface mounting technology (SMT) machines defines the pace of PCB production because of time consuming and critical process. In addition, it is observed that various planning and scheduling problems exist in PCB assembly line which are required to emphasize to increase the productivity. Therefore, in this study critical planning and scheduling problems i.e., component allocation problem (CAP) and component placement sequence problem (CPSP) are considered to optimize. Moreover, the periodic maintenance (PM) is also considered to maintain the efficiency of machines and make the problem more realistic. A mathematical model is formulated to minimize the maximum completion time, total energy consumption and the total maintenance time simultaneously. To solve this multi-objective NP-hard problem, an improved spider monkey optimization (ISMO) algorithm is developed. The efficiency and effectiveness of ISMO algorithm is improved by embedding few additional features. a) Two heuristics to ensure better initial solutions; b) evolutionary state judgment based on change in Pareto entropy to ensure the tradeoff between exploration and exploitation; c) an archive-based Q-Learning strategy to ensure the parametric adaptive tuning. Finally, computational experiments and comprehensive performance comparisons with other well-known multi-objective algorithms are performed with several size problem instances. The statistical results and analysis demonstrate that the proposed ISMO algorithm outperforms the other competitors.

Unveiling High Performance Solder Alloys for Automotive Applications

Vehicle electrification and advances in autonomous driving technologies are creating unique opportunities and challenges in the automotive electronics assembly industry. The ever-increasing demand of reliability at higher temperatures and longer service life, especially for automotive electronics, is leading to the evolution of high reliability solder alloy design in the electronics assembly industry. The combination of harsh operating conditions, increasing power densities, and miniaturization has added to the complexity of assembly designs in the automotive electronics market for which traditional surface mount solders are no longer applicable. Thermo-mechanical reliability of solder alloys under harsh operating conditions has been a primary factor for defining suitability and selection of solder alloy for next generation designs. A next generation high reliability alloy for automotive electronics is introduced herein. The microstructure of this novel alloy consists of a well-distributed eutectic phase and finely distributed precipitates of intermetallic compounds which contributes towards solid solution strengthening as well as precipitation strengthening. It is shown that a high-temperature superior creep strength improvement of more than 100% over existing high reliability alloys is achieved at temperatures of 150°C. This and other mechanical properties of the bulk alloy are then correlated to performance with thermal cycling testing under extreme conditions. The novel alloy showed significantly higher thermal cycling performance, exhibiting more than 40% increase in the characteristic life over other existing high-reliability alloys while maintaining traditional surface mount target reflow temperatures. Considering these results, this new class of alloys has the capability to meet the increasingly challenging reliability requirements of automotive electronics.

Design and analysis of compact dual‐band WPT system using capacitively loaded interdigital capacitor

SummaryIn this paper, a noteworthy compact dual‐band wireless power transfer (DB‐WPT) system is presented and studied. This DB‐WPT system is proposed using a capacitively loaded interdigital capacitor which reduces the size of the whole system, lessens the number of the attached surface mount elements, and accomplishes high efficiencies. An interdigital capacitor is printed in the ground plane of the design and loaded with a chip capacitor to produce dual bands. The operation of the system is verified by fabricating the proposed DB‐WPT system, which shows measured coupling efficiencies of 96% and 98.8% at 0.53 and 1.1 GHz, respectively at a transfer space of 12 mm. The fabricated structure has dimensions of 13.5 mm × 20 mm. The results show good agreement between the circuit model and the measurements. The idea of this design makes it applicable for compact near‐field WPT applications.

Influence of a PCB Layout Design on the Efficiency of Heat Dissipation and Mutual Thermal Couplings between Transistors

This article presents the results of the investigations concerning the influence of the printed circuit board (PCB) layout design on self and transfer transient thermal impedances characterizing thermal phenomena occurring in the network containing two power MOSFETs. The tested devices have the case D2PAK and are soldered to the PCB using the surface mount technology (SMT). The measurement method is described. The tested transistors are presented with the used PCBs on which they are mounted. The obtained measurement results of the mentioned thermal parameters of the tested transistors operating on all the tested PCBs are shown and discussed. The influence of a cooling area of the tested PCBs on the parameters describing self and transfer transient thermal impedances is analyzed.

Speed Control of PMSM Based on Fuzzy Active Disturbance Rejection Control under Small Disturbances

Permanent Magnet Synchronous Motors (PMSMs), with their simple design, small size, and high-power factor, are ideally suited for realizing high-power AC drives and are widely used in various industries. In this study, Fuzzy Active Disturbance Rejection Control (Fuzzy-ADRC) is used to control the speed of the PMSM. When a slight external disturbance occurs, this control strategy maintains the suppression characteristics of the self-excited control for the disturbance and enhances its ability to compensate for the disturbance. First, a mathematical model was developed to study the surface mount PMSM. Then, a motor control simulation model was created using PI control, vector control, and other control methods. The verification results indicate that the improved Fuzzy-ADRC system performs well under both internal and external minor disturbances. It exhibits a faster dynamic response and reduced regulation time (0.026 s to 0.017 s) compared to the traditional ADRC system. Furthermore, it shows less overshoot (reduced from 70% to 2.9%) compared to the Sliding Mode Observer (SMO). Taken together, the improved Fuzzy-ADRC system is characterized by small steady-state error, high load capacity, and control accuracy. With the assistance of this control strategy, the system can track speed with high accuracy and possesses stronger anti-interference capability to mitigate load disturbances.

Effect of PVD-coated wall aperture roughness on the life span of fine-pitch stencil printing

PurposeThis paper aims to investigate the effect of physical vapor deposition (PVD)-coated stencil wall aperture on the life span of fine-pitch stencil printing.Design/methodology/approachThe fine-pitch stencil used in this work is fabricated by electroform process and subsequently nano-coated using the PVD process. Stencil printing process was then performed to print the solder paste onto the printed circuit board (PCB) pad. The solder paste release was observed by solder paste inspection (SPI) and analyzed qualitatively and quantitatively. The printing cycle of up to 80,000 cycles was used to investigate the life span of stencil printing.FindingsThe finding shows that the performance of stencil printing in terms of solder printing quality is highly dependent on the surface roughness of the stencil aperture. PVD-coated stencil aperture can prolong the life span of stencil printing with an acceptable performance rate of about 60%.Originality/valueStencil printing is one of the important processes in surface mount technology to apply solder paste on the PCB. The stencil’s life span greatly depends on the type of solder paste, stencil printing cycles involved and stencil conditions such as the shape of the aperture, size and thickness of the stencil. This study will provide valuable insight into the relationship between the coated stencil wall aperture via PVD process on the life span of fine-pitch stencil printing.

Experimental Analysis of an Innovative Double Strap Joint Splicing of GFRP Bars by NSM Methods for Strengthening RC Beams

The double strap joint splicing of glass fiber reinforced polymer (GFRP) bars for reinforced concrete (RC) beams strengthening, applying the near surface mounting (NSM) method, has been proposed in the paper. The proposed method consists of application of the supplementary GFRP bars symmetrically positioned in the cut-off zone of the main GFRP reinforcement. The performances of this splicing method have been experimentally tested for the most unfavorable case of the GFRP reinforcement cut-off in the maximal bending moment zones. During the experiment, the varied parameter has been overlapping length of the bars, taking values of 20∅ and 40∅. Evaluation of the splicing technique is done comparing the experimental results with the results of the behavior of beams strengthened by GFRP bars without cut-off and with cut-off, but without splicing. Experimental research encompassed analysis of strength, stiffness, ductility, crack pattern, strains in the steel, GFRP reinforcement and concrete, and the failure modes of the beams. It has been shown that in case of the cut-off of the GFRP bar, strengthening effectivity decreases for 39%, and that in the case of bypassing the cut-off using double strap 20∅ and 40∅ long, strengthening effectivity decreased 23%, and 14% respectively, compared to the beam without GFRP bar cut-off. Using extrapolation, it has been shown that double strap with length of 60∅ provided strength equivalent to the case without cut-off. The result of application of this splicing method of the additional GFRP bars is significant increase of strength and serviceability of the strengthened RC beams.

Review of retrofitting techniques of deteriorated reinforced concrete columns

To ensure sustainability, all types of building structures should be kept in accepted condition throughout their life of service. Rehabilitation has been the subject of extensive research recently because of rising spending on construction and maintenance of constructed infrastructure. The most recent methods to reinforce current reinforced concrete columns, including both conventional and cutting-edge strengthening procedures, are presented in this study. Frequently, general materials used in repairing on-service reinforced concrete columns are concrete, steel, and different kind of Fiber Reinforced Polymer (FRP) composites. Conventional methods and procedures for different mode of failures strengthening, including all types of FRP procedures Near Surface Mounting (NSM) reinforcement, Externally Bonded (EB) FRP, and textile reinforced concrete will all be included in the discussion, and FRP pre-stressing methods for modifying existing structures.

Numerical Modeling, Experimental Investigation, and Optimization of a Micro Hot Embossing Process

Abstract This paper describes the development of a finite element simulation model and a self-made low-cost experimental setup for the micro hot embossing process. The simulation model incorporates stress relaxation behavior through the utilization of the generalized Maxwell model. It also considers thermal expansion and contact friction effects, enabling accurate prediction of the deformed pattern of polymethyl methacrylate (PMMA). Simulations and experiments were performed for various pressure and temperature combinations, and the resulting pattern profile depths were found to be in good agreement, between the simulation and experimental results. In addition, the simulation model was used to generate response surfaces through face-centered central composite design (CCD) to identify the ideal combination of process parameters of the micro hot embossing process for creating a patterned SMD (surface mount device) LED chip panel.

Surface mount multilayer ceramic capacitors as optically stimulated luminescent dosimeters

The choice of dosimetric materials for precise retrospective dose assessment in case of any emergencies is very challenging. Since few decades, electronic components like ceramic resistors, inductors, IC chips, surface mount resistors and inductors have been proven to be suitable candidates for dose estimation using thermoluminesce (TL)/optically stimulated luminescence (OSL) techniques. In this work, OSL technique is applied to study dosimetric properties of surface mount multilayer ceramic capacitors (SM MLCC) available in commonly used instruments like printer, computer mouse, USB flash drive and personal gadgets like mobile phone etc. To understand the OSL process involved, the elemental composition and crystallinity of the SM MLCCs were analyzed using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) techniques. It is found that the main constituent is barium titanate with aluminium silicate as major impurity along with some trace elements and is responsible for the origin of the radiation induced OSL signal. Some important dosimetric characteristics like OSL sensitivity, repeatability, OSL dose response, and OSL signal stability upon storage were studied. The stimulation time was optimized as 50 s and used for all OSL measurements. The dose response was found to be linear from 500 mGy to 15 Gy and simply increased (up to 40 Gy). Fading analysis showed that the OSL signal decreases by ∼ 25 % in 1 day, ∼ 50 % in 4 days, and remained stable after that at least up to 8 days. The dose was recovered using single aliquot regenerative-dose (SAR) technique with very good accuracy. These results of dosimetric studies and validation study suggest that surface mount multilayer ceramic capacitors have potential use as retrospective dosimeters.

Effect of Differently Shaped Solder Joints of Chip Resistor on Fatigue Life

Abstract As surface mount components shrink in size, smaller apertures on stencils during solder paste printing can lead to uneven solder volume on a single resistor. This can result in the formation of irregular solder shapes, which are often deemed acceptable criterion depending on assembly house. However, such irregularities can potentially introduce variations in the fatigue life of the surface mount component. This study employs experimental and numerical approaches to investigate the reliability of differently shaped SAC305 solder joints on a single chip resistor. Four distinct solder shapes, concave, straight, tiny convex, and convex, are generated using varying volumes of solder paste controlled by uniquely designed apertures on a stencil. Eight pairs of differently shaped solder joints are assembled to hold a chip resistor in place. The test assembly involves R1005 and R0402 soldered with SAC305 and undergoes thermal shock cycling. As a single chip resistor assembly consists of two solder joints connecting termination and pads, the effect of solder volume difference between two solder joints are investigated. The fatigue life corresponds to decrease as the solder volume difference increase as 40%, 80%, and 120%. Conversely, total volume of two solder joints in a single chip resistor increases in scenarios with the same volume difference between two solder joints. Experimental data and finite element analysis lead to a new set of Darveaux's constants specific to this assembly. This study provides guideline to control the solder paste volumes in relation to fatigue life and enables numerical solution using a new Darveaux's constants.