Surface Mount Research Articles

Cost-Effective Surface-Mount Off-Center-Fed Dipole Antenna Element and Its Array for 5G Millimeter Wave New Radio Applications

A cost-effective ball grid array (BGA) packaged surface-mount off-center-fed dipole antenna element and its array are proposed for 5G millimeter-wave new radio (NR) applications. The proposed antenna element exhibits a compact size of 0.61 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.61 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.16 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ( λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> is the wavelength in free space at the center operating frequency) and is realized by only one FR4 layer to minimize cost. Plated through holes (PTHs) connect the dipole patch on the top layer to the bottom layer. Furthermore, tin-lead solder balls are mounted under the bottom layer to form the BGA packaging. The surface-mountable feature enables the antenna element to be integrated with other surface mount devices without any waveguide or coaxial connectors. The evaluation board uses a 50- Ω grounded coplanar waveguide (GCPW) line to test the performance of the antenna element and array. The antenna prototype and evaluation board have been manufactured and measured. The measurement results show that the -10-dB impedance bandwidth of the proposed antenna element achieves 35.7% in the range of 25.1-36 GHz. The measured peak gains of the antenna element and the 1 ×8 arrays are 6.72 and 13.53 dBi, respectively.

Parameter Optimization of Pretin Printing Process of Wireless Communication Module

For system manufacturers, packaging of the ball grid array (BGA) of wireless communication modules can be performed via solder paste printing. As reballing can be conducted via the pretinning process, it can be compatible with its existing surface mount technology (SMT). This study referred to the Taguchi experimental design to plan its experiment. Three quality characteristics related to the consistency of the solder volume are applied for printing, that is, the standard deviation of the deposition volume of solder paste on all bonding pads of a single component, the coplanarity of the solder balls of the component, and the height range of the solder ball of a single component, which were regarded as the response values. Important design and process parameters related to the pretinning process and the relative location of the bonding pads of components on a connecting board are considered as the controlling factors. Then, this study applied and integrated the results of two multivariate analysis methods, i.e., gray correlation of the principal components and a technique for order preference by similarity to ideal solution (TOPSIS), in order to determine the ideal solution and propose the optimal parameter combination: general squeegee: pressure 40 N and speed 30 mm/s; steel: separation distance 3 mm, speed 2 mm/s, and aspect ratio 0.17; and cleaning frequency: cleaning of stencils after the printing of every two boards. This method effectively improves the control of the solder volume in the pretinning process and meets the acceptance criteria of manufacturers.

Design and investigation of a high integrated reliable ceramic package for surface mount technology

With the development of automobile, communication, computer, aerospace and artificial intelligence, Small Outline Packages (SOP) are difficult to meet the needs of putting more integrated circuits, analog-digital signal processing circuit, storage or multi-functional modules into one package, and letting them work on the same voltage for compacted space and high reliable application. Unlike conventional SOP packages, a ceramic package of CSOP64 with larger outline and bigger cavity is designed and fabricated for surface mount technology in this paper. Also fairly strict conditions of environmental reliabilities compared to criterions commonly used on accelerated testing, such as temperature cycling, thermal shock, mechanical shock, constant acceleration and gas leakage are carried out to assure the reliabilities of package. Coffin-Manson model, dual capillary model, finite element simulation and theory calculation methods are applied to explain the mechanism of reliability problems in this investigation. Experiment results showed that all samples passed tests. The reliability of fabricated package samples meet the requirement in application.

Controlling atomic phosphorous-mounting surfaces of ultrafine W2C nanoislands monodispersed on the carbon frameworks for enhanced hydrogen evolution

Controllably mounting foreign atoms on the surfaces of earth-abundant electrocatalysts strongly improve their surface electronic properties for optimizing the catalytic performance of surficial sites to an unusual level, and provides a good platform to gain deep insights into catalytic reactions. The present work describes, employing ultrafine W2C nanoislands (average size: 2.3 nm) monodispersed on the N, P dual-doped carbon frameworks as a model system, how to regulate the atomic phosphorous-mounting effect on the surfaces of W2C to derive an active and stable P-mounting W2C (WCP) catalyst for both acidic and alkaline hydrogen evolution reaction (HER). Since in situ phosphorus substitution into carbon sites of preformed W2C nanoislands gradually proceeds from surfaces to solids, so that using a proper amount of phosphorus sources can readily control the surface mounting level to avoid the mass P-doping into the bulk. By this way, the activity per active site of WCP catalyst with robust stability can be optimized to 0.07 and 0.56 H2 s−1 at –200 mV overpotential in acid and base, respectively, which reach up to the several-fold of pure-phase W2C (0.01 and 0.05 H2 s−1). Theoretical investigations suggest that compared with solid P doping, the P mounting on W2C surface can more remarkably enhance its metallicity and decrease the hydrogen release barrier. This finding disclosed a key correlation between surface foreign atom-mounting and catalytic activity, and suggested a logical extension to other earth-abundant catalysts for various catalytic reactions.

Improving the sensitivity of statistical process monitoring of manifolds embedded in high-dimensional spaces: The truncated-Q statistic

We address the limitations of applying the well-known Q/SPE statistic for statistical process monitoring (SPM) on manifolds embedded in high-dimensional systems. Our analysis considers scenarios where the number of samples used for deriving the control limits during Phase I analysis is small regarding the number of variables to monitor, which is the prevalent situation in modern industry. After diving into the root causes of some problems associated with the implementation of SPM in large-scale processes, we propose an alternative residual statistic, called the truncated-Q statistic (QΔ) and the associated control limit. The sensitivity of the new statistic for sensor faults is analyzed through a Monte Carlo study involving processes of different dimensionalities and correlation structures, under different testing conditions. A significant improvement in detection sensitivity is observed, especially when the dimensionality of the process is high and the faults have low magnitudes and only affect a few sensors. The practical relevance of this finding is discussed in the paper and further corroborated with a real case study from an industrial Surface Mount Technology (STM) process. The truncated-Q statistic, whose code is made available, can be readily extended to linear and non-linear manifolds embedded in high-dimensional systems.

Experimental measurements of the shear force on surface mount components simulating the wave soldering process

PurposeThis study aims to determine the minimum force required to pull out a surface mount component in printed circuit boards (PCBs) during the wave soldering process through both experimental and numerical procedures.Design/methodology/approachAn efficient experimental technique was proposed to determine the minimum force required to pull out a surface mount component in PCBs during the wave soldering process.FindingsThe results showed that the pullout force is approximately 0.4 N. Comparing this value with the simulated force exerted by the solder wave on the component ( 0.001158 N), it can be concluded that the solder wave does not exert sufficient force to remove a component.Originality/valueThis study provides a deep understanding of the wave soldering process regarding the component pullout, a critical issue that usually occurs in the microelectronics industry during this soldering process. By applying both accurate experimental and numerical approaches, this study showed that more tests are needed to evaluate the main cause of this problem, as well as new insights were provided into the depositing process of glue dots on PCBs.

Electroplating of Aerosol Jet‐Printed Silver Inks

Aerosol jet printing of silver inks is a promising approach for 3D printing of electronics, particularly for obtaining very complex circuits with high‐resolution conductive pads and traces. Common silver inks are however not competitive with traditional bulk metal conductors, requiring sintering at high temperatures as well as having significant porosity that can result in early failure. Herein, the possibility of using electroplating to deposit bulk metal copper on aerosol jetted inks is investigated, and more than an order of magnitude reduction in electrical resistivity is shown. The plating rate, resistivity, and adhesion are characterized, along with the morphology of the resulting deposits. This approach is then shown to allow high‐strength soldering to the electroplated metal traces, demonstrating the capability of this technology for integration of soldered surface mount components with aerosol jet‐printed electronics.

Electronic component detection based on image sample generation

PurposeThis paper aims to propose a deep learning model that can be used to expand the number of samples. In the process of manufacturing and assembling electronic components on the printed circuit board in the surface mount technology production line, it is relatively easy to collect non-defective samples, but it is difficult to collect defective samples within a certain period of time. Therefore, the number of non-defective components is much greater than the number of defective components. In the process of training the defect detection method of electronic components based on deep learning, a large number of defective and non-defective samples need to be input at the same time.Design/methodology/approachTo obtain enough electronic components samples required for training, a method based on the generative adversarial network (GAN) to generate training samples is proposed, and then the generated samples and real samples are used to train the convolutional neural networks (CNN) together to obtain the best detection results.FindingsThe experimental results show that the defect recognition method using GAN and CNN can not only expand the sample images of the electronic components required for the training model but also accurately classify the defect types.Originality/valueTo solve the problem of unbalanced sample types in component inspection, a GAN-based method is proposed to generate different types of training component samples and then the generated samples and real samples are used to train the CNN together to obtain the best detection results.

Simple Design of a Wideband and Wide-Angle Insensitive Metamaterial Absorber Using Lumped Resistors for X- and Ku-Bands

We report a wideband and polarization-/wide-angle insensitive metamaterial absorber based on a symmetry structure associated with surface mount resistors. The proposed structure consists of a periodic array of a top metal symmetry resonator loading with four lumped resistors and a continuous metal ground plane separated by a dielectric substrate of FR-4. A prototype of the proposed absorber is fabricated and measured, confirming a good agreement between the measurement and simulation results. The proposed absorber shows polarization-insensitive behavior and the absorption response in a frequency range from 8-18 GHz covering the entire X- and Ku- bands with an absorptivity above 80$\%$ for a wide incident angle up to 40 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">°</sup> for both transverse electric and transverse magnetic polarizations. Compared with the reported broadband absorbers using lumped resistors, our proposed absorber exhibits excellent characteristics in terms of compact and simple structure, high relative absorption bandwidth, and polarization and wide-incident insensitivity. Therefore, this design shows promising potential for both X- and Ku-band applications.

The effect of variable irradiation mask in Focused Infrared Light Soldering Systems for electronic components

The surface mount technology (SMT) has allowed to include more electronic components with different shapes and sizes on printed circuit boards (PCB), improving the storage capabilities, transmission rates, and data processing; also, some optical elements have been incorporated in their composition. Therefore, an evolution in the methods and processes of non-contact soldering is required to adhere the elements without damaging them. In the present paper is presented the irradiance analysis when a Variable Irradiation Mask (VIM) is inserted in the output of a focused infrared soldering system (FILSS) to obtain a different light distribution, which can be compared with the thermal distribution obtained in the electronic component that is being analyzed, a Ball Grid Array (BGA) in this case. The results of irradiance in the simulation are congruent with thermal distribution obtained experimentally in the study area of the target's surface. It is observed that at the borders with the VIM, 50% of the total intensity of the máximum termal distribution is obtained. The soldering quality in the electronic component can be correlated with the thermal distribution and irradiance in this system.

Optimization of the Rapid Design System for Arts and Crafts Based on Big Data and 3D Technology

In this paper, to solve the problem of slow design of arts and crafts and to improve design efficiency and aesthetics, the existing big data and 3D technology are used to conduct an in-depth analysis of the optimization of the rapid design system of arts and crafts machine salt baking. In the system requirement analysis, the functional modules of this system are identified as nine functional modules such as design terminology management system and external information import function according to the actual usage requirements. In the system design, the overall structure design, database design, and functional module design of the system are comprehensively elaborated, and the key issues such as 3D display and home layout generation algorithm based on reinforcement learning are analyzed and designed. In the implementation part of the system, the overall construction of the system and the composition of functional modules are introduced in detail and the main functional modules of the system are presented with interface diagrams. In the system implementation part, the overall system construction and functional module composition are introduced in detail, the main functional modules of the system are shown with interface diagrams, codes, and algorithms, and the specific implementation process of 3D display and soft layout algorithms are also explained in detail. The process of Surface Mount Technology (SMT) big data processing and analysis is designed, and the design of SMT production line data collection scheme and real-time data processing architecture is completed. Based on the characteristics of SMT production line data, the K-means algorithm is used to detect data outliers and verify the accuracy of the method; also, the Spark-based association rule printing parameter recommendation model is designed, and the efficiency of the Apriori algorithm is significantly improved by parallelization.

A novel placement method for mini-scale passive components in surface mount technology

This paper aims to propose a novel placing method, i.e., place-between-paste-and-pad (PB), for mini-scale passive components to enhance electronic assembly lines’ yield. PB means a component is designed to be placed at the midpoint between the pastes and pads on the length direction while it aligns with the pads’ center on the width direction. An experiment that involves 12 printed circuit boards (PCB) and 4500 resistors R0402M (0.40 mm × 0.20 mm) is designed and conducted to get comparative results of PB and two industrial placing methods, i.e., place-on-pad and place-on-paste. Based on this experiment’s results, PB outperforms the other two methods in terms of minimizing the components’ final misalignment. Furthermore, PB is a low-cost placing strategy because PB does not need the real-time communication between the solder paste inspection machine and the pick-and-place machine. The placement method proposed in this study is expected to offer a low-cost exploration in the pick-and-place procedure to enhance the surface mount assembly quality of mini-scale passive components.

Simulation of jet printing of solder paste for surface mounted technology

Purpose The purpose of this study is to propose a novel simulation framework and show that it captures the main effects of the deposition process, such as droplet shape, volume and speed. Design/methodology/approach In the framework, the time-dependent flow and the fluid-structure interaction between the suspension, the moving piston and the deflection of the jetting head is simulated. The system is modelled as a two-phase system with the surrounding air being one phase and the dense suspension the other. The non-Newtonian suspension is modelled as a mixed single phase with properties determined from material testing. The simulations were performed with two coupled in-house solvers developed at Fraunhofer-Chalmers Centre; IBOFlow, a multiphase flow solver; and LaStFEM, a large strain FEM solver. Experimental deposition was performed with a commercial jet printer and quantitative measurements were made with optical profilometry. Findings Jetting behaviour was shown to be affected by not only piston motion, fluid rheology and head deformation but also the viscous energy loss in the jetting head nozzle. The simulation results were compared to experimental data obtained from an industrial jetting head and found to match characteristic lengths, speed and volume within ca 10%. Research limitations/implications The simulations are based on a rheological description using the Carreau model that does not include a time-dependent relaxation of the fluid. This modelling approach limits the descriptive nature of the deposit after impact on the substrate. The simulation also adopts a continuum approach to the suspension, which will not accurately model the break-off of the droplet filament under the characteristic diameter of the particles in the suspension. Practical implications The ability to accurately simulate the deposition of functional materials will enable the efficient development of novel product designs with a minimum of used resources and minimised product development duration. Social implications The ability to accurately simulate the deposition of functional materials will enable the efficient development of novel product designs with a minimum of used resources and therefore an improvement from a sustainability perspective. The ability to plan deposition strategies virtually will also enable a decrease in consumables at manufacturers which will in turn decrease their carbon foot print. Originality/value While basic fluid dynamic simulations have been performed to simulate flow through nozzles, the ability to include both fluid-structure interaction and multiphase capability together with a more accurate rheological description of the suspension and with a substrate for surface mount applications has not been published to the knowledge of the authors.

Challenges in Minimizing Copper Dissolution for Lead Free Wave Soldering in Surface Mount Technology Going Towards Green Manufacturing

In surface mount technology, development toward green manufacturing by converting all leaded soldering processes to lead free soldering process has created a lot of challenges mainly in wave soldering process which led to copper dissolution to assemble board causing it to be scrapped if not contained. The paper aims to propose a workable and practical solution to reduce extensive copper dissolution in assemble board and expand the cycle of allowable rework in assemble board. The work was carried out using Six Sigma methodology with defining the problem and research goals, measure the details in various aspects of current process, analyse data to identify potential root cause in a process, improve the process and control the process through experimental approaches. Main factors contributing to copper dissolution were identified and analysed. Total of five factors were identified namely the printed circuit board (PCB) finishing and copper layer construction in PCB, component terminal and led finishing, soldering flux usage and solder alloy composition, environment control with the use of Nitrogen tunnelling and the last factor was on the process itself which was from the in-contact process with molten turbulence soldering or non-contact process with intrusive soldering. Combined controlled factors contributing to minimization of copper dissolution by reducing the direct contact time to molten solder with optimize solder alloy composition and process control was formulated. An increase of sixty percentage of boards with lower copper dissolution going through the lead free wave soldering and rework soldering were obtained, another forty percent reduction of board being scrapped were also obtained with boards going through the molten solder up to triple times.

Substrate‐Versatile Direct‐Write Printing of Carbon Nanotube‐Based Flexible Conductors, Circuits, and Sensors

AbstractManufacturing of printed electronics relies on the deposition of conductive liquid inks, typically onto polymeric or paper substrates. Among available conductive fillers for use in electronic inks, carbon nanotubes (CNTs) have high conductivity, low density, processability at low temperatures, and intrinsic mechanical flexibility. However, the electrical conductivity of printed CNT structures has been limited by CNT quality and concentration, and by the need for nonconductive modifiers to make the ink stable and extrudable. This study introduces a polymer‐free, printable aqueous CNT ink, and, via an ambient direct‐write printing process, presents the relationships between printing resolution, ink rheology, and ink‐substrate interactions. A model is constructed to predict printed feature sizes on impermeable substrates based on Wenzel wetting. Printed lines have conductivity up to 10 000 S m−1. The lines are flexible, with &lt;5% change in DC resistance after 1000 bending cycles, and &lt;3% change in DC resistance with a bending radius down to 1 mm. Demonstrations focus on i) conformality, via printing CNTs onto stickers that can be applied to curved surfaces, ii) interactivity using a CNT‐based button printed onto folded paper structure, and iii) capacitive sensing of liquid wicking into the substrate itself. Facile integration of surface mount components on printed circuits is enabled by the intrinsic adhesion of the wet ink.

Novel NSM configuration for RC column strengthening-A numerical study

Retrofitting of structures has gained importance over the recent years. Particularly, Reinforced Cement Concrete (RCC) column strengthening has become a challenge to the structural engineers, owing to the risks and complexities involved in it. There are several methods of RCC column strengthening viz. RCC jacketing, steel jacketing and Fiber Reinforced Polymer (FRP) wrapping etc., FRP wrapping is the most promising alternative when compared to the others. The large research database shows FRP wrapping, through lateral confinement, improves the axial load carrying capacity of the columns under concentric loading. However, its confining efficiency reduces under eccentric loading. Hence a relative newer technique called Near Surface Mounting (NSM), in which Carbon FRP (CFRP) strips are epoxy grouted to the precut grooves in the cover concrete of the columns, has been thrust domain of research. NSM technique strengthens the column nominally under concentric load case while significantly under eccentric case. A novel configuration of NSM in which the vertical NSM (VNSM) strips are being connected by horizontal NSM (HNSM) strips was numerically investigated under both concentric and eccentric loading. It was found that the configuration with 6 HNSM strips performed better under eccentric loading than under concentric loading, while the configuration with 3 HNSM strips performed better under concentric loading than under eccentric loading. Hence an optimum of 4 HNSM strips is recommended as strengthening measure for the given column specifications. It was also found that Aluminum alloy cannot be used instead of CFRP in NSM applications owing to its lower mechanical properties.

Design of a high power density Halbach BLDC motor for an electric vehicle propulsion

The electric drives used for vehicle propulsion need to be highly efficient and high power dense to improve the performance of electric vehicles (EV) and make them competent in transportation applications. In the similar lines, this paper proposes a radial flux brushless direct current (BLDC) motor with surface magnet rotor with a Halbach array. The magnetic equivalent circuit of the motor is derived; nonlinear electromagnetic analysis carried out and arrived at performance characteristics for an EV propulsion. The proposed topology is compared with conventional BLDC motor with surface mount magnets and found an increment of 20% in power density. The hardware is realized, tested for its performance and the results are closely matching with design parameters.

Development and characterization of an LED-based detector for dosimetry in diagnostic radiology

Light-emitting diodes (LEDs) could be a potential dosimetry candidate because they are radiation hard, spectrally selective, direct band gap, and low-cost devices. Thus, an LED-based detector prototype was designed and characterized for dosimetry. A 20 × 20 cm2 array of surface mount device LED chips was sandwiched in photovoltaic mode between two intensifying screens to form a dosimetric system. The system was enclosed in a light-tight air cavity using black vinyl tape. The screens converted diagnostic x-ray beams into fluorescent blue light. LEDs, applied in detector mode, converted the fluorescent light into radiation-induced currents. A digital multimeter converted the analog currents into digital voltage signals. Prototype characterization was executed using (a) IEC 61267’s RQR 7 (90 kVp) and RQR 8 (100 kVp) beam qualities, and (b) low (25 mAs) and high (80 mAs) beam quantities. A standard dosimeter probe was simultaneously exposed with the prototype to measure the prototype’s absorbed dose. In all exposures, the x-ray beams were perpendicularly incident on both the dosimeter and prototype, at a fixed source to detector distance-60 cm. The LED array prototype’s minimum detectable dose was 0.139 mGy, and the maximum dose implemented herein was ∼13 mGy. The prototype was 99.18% and 98.64% linearly sensitive to absorbed dose and tube current–time product (mAs), respectively. The system was ±4.69% energy, ±6.8% dose, and ±7.7% dose rate dependent. Two prototype data sets were 89.93% repeatable. We fabricated an ultrathin (5 mm), lightweight (130 g), and a relatively low-cost LED-based dosimetric prototype. The prototype executed a simple, efficient, and accurate real-time dosimetric mechanism. It could thus be an alternative to the current passive dosimetric systems.

Fan-Out Panel-Level Packaging of Mini-LED RGB Display

In this study, the feasibility of mini-light-emitting diode (LED) RGB display fabricated by a chip-first fan-out panel-level packaging is investigated. Emphasis is placed on the design, materials, process, fabrication, and reliability of the mini-LED RGB display package on a printed circuit board (PCB). The mini-LEDs under consideration and their sizes are red ( 125 ×250 ×100 μm), green ( 130 ×270 ×100 μm), and blue ( 130 ×270 ×100 μm). The spacing among the RGB mini-LEDs is 80 μm, the pixel-to-pixel spacing is also ~ 80 μm, and the pixel pitch is 625 μm. The temporary glass panel for making the redistribution layers (RDLs) of the package is 515 ×510 ×1.1 mm in size. To increase the SMT assembly yield on the PCB, the mini-LEDs are grouped into 4( 2 ×2 pixels)-in-one surface mount device (SMD), that is, a total of 12 R, B, and G mini-LEDs. A PCB ( 132 mm ×77 mm) is designed and fabricated for the drop test of the mini-LED package. Thermal cycling of the mini-LED SMD PCB assembly is also performed by a nonlinear temperature- and time-dependent finite-element simulation.

Simulation and analysis of marine strong magnetic surface-mounted shield

In the course of the ship’s navigation, a strong magnetic surface mount method is used to realize real-time observation of the temperature and salt elements of the sea surface. In order to ensure the stability of the magnetic module (the shield) during navigation, the force condition was analyzed with ANSYS Fluent, and a design calculation method was proposed. Firstly, numerical simulation analysis is carried out on the force of the shield. Secondly, the magnetic force of permanent magnets with different sizes is calculated. Through the analysis of the overall force, the size and total number of magnets required on the shield are finally determined.