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1 – 10 of 353Aleksandar B. Menićanin, Mirjana S. Damnjanović and Ljiljana D. Živanov
The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant consideration…
Abstract
Purpose
The appropriate selection of a testing method largely determines the accuracy of a measurement. Parasitic effects associated with test fixture demand a significant consideration in a measurement. The purpose of this paper is to introduce a measurement procedure which can be used for the characterization of surface mount devices (SMD) components, especially devoted to SMD inductors.
Design/methodology/approach
The paper describes measurement technique, characterization, and extracting parameters of SMD components for printed circuit board (PCB) applications. The commercially available components (multi‐layer chip SMD inductors in the ceramic body) are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. Measurement results strongly depend on the choice of the PCB; the behaviour of the component depends on the environment where the component is placed.
Findings
The equivalent circuit parameters are extracted in closed form, from an accurate measurement of the board‐mounted SMD inductor S‐parameters, without the necessity for cumbersome optimization procedures, which normally follow the radio frequency circuit synthesis.
Originality/value
It this paper, a new adaptation test fixture in PCB technology is realized. It is modeled and it has provided the extraction of parameters (intrinsic and extrinsic) of SMD inductor with great accuracy.
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Jose James, Bhavani Rao R. and Gabriel Neamtu
Offering unskilled people training in engineering and vocational skills helps to decrease unemployment rate. The purpose of this paper is to augment actual hands-on conventional…
Abstract
Purpose
Offering unskilled people training in engineering and vocational skills helps to decrease unemployment rate. The purpose of this paper is to augment actual hands-on conventional vocational training methods with virtual haptic simulations as part of computer-based vocational education and training.
Design/methodology/approach
This paper discusses the design of a bi-manual virtual multi-modal training interface for learning basic skills in surface mount device hand soldering. This research aims to analyze human hand dexterity of novices and experts at micro level skill knowledge capture by simulating and tracking the users’ actions in the manual soldering process through a multi-modal user interface.
Findings
Haptic feedback can enhance the experience of a virtual training environment for the end user and can provide a supplementary modality for imparting tangible principles to increase effectiveness. This will improve the teaching and learning of engineering and vocational skills with touch-based haptics technology, targeted toward teachers and students of various disciplines in engineering. Compared with the traditional training methods for learning soldering skills, the proposed method shows more efficiency in faster skill acquisition and skill learning.
Originality/value
In this study, the authors proposed a novel bi-manual virtual training simulator model for teaching soldering skills for surface mount technology and inspection. This research aims to investigate the acquisition of soldering skills through virtual environment, with and without haptic feedback. This acts as a basic-level training simulator that provides introductory training in soldering skills and can help initially unskilled people find educational opportunities and job offers in the electronics industry.
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Muna Raypah, Mutharasu Devarajan and Shahrom Mahmud
The presence of voids in the solder layer has been considered as one of the main issues causing reliability problems in optoelectronic devices. Voids can be created due to trapped…
Abstract
Purpose
The presence of voids in the solder layer has been considered as one of the main issues causing reliability problems in optoelectronic devices. Voids can be created due to trapped gas, clean-up agent residues (fluxes), poor wettability at interface or shortcoming of the reflow process. The voids hinder the heat conduction path and subsequently, the thermal resistance will increase. The purpose of this paper is to investigate the influence of lead-free water-washable Sn96.5Ag3.0Cu0.5 (SAC305) solder paste (SP) voids on the thermal and optical performance of white high-power (HP) surface-mounted device (SMD) light-emitting diode (LED).
Design/methodology/approach
Five LEDs are mounted on five SinkPAD substrates by using the SP. The SMT stencil printing is used to control the thickness of the SP and reflow oven for the soldering process. The fraction of voids in the SP layer is calculated using the X-ray machine software. The thermal parameters of the LEDs with different voids fraction and configuration are measured using a thermal transient tester (T3Ster) system. In addition, the optical characterizations of the LEDs are determined by the thermal and radiometric characterization of power LEDs (TeraLED) and the electroluminescence by using the spectrometer.
Findings
The results showed that the thermal performance and temperature distribution are improved for the LED with lower voids fraction and good filling state of soldering. In addition, luminous flux, efficacy and color shift of the LEDs with different fraction and configurations of voids on the SP layer are compared and discussed. It is found that the color shift of LED1 of low voids fraction and higher thickness are less than other LEDs.
Originality/value
The paper provides valuable information about the effect of water-washable SAC305 SP voids fraction and filling state of solder on the thermal and optical performance of ThinGaN HP SMD LED. A comprehensive overview of the outcomes is not available in the literature. It was shown experimentally that the voids fraction, height and configuration of the SP layer could strongly influence the heat dissipation efficiency and thermal resistance. This study can help in heat diffusion investigation and failure analysis of HP SMD LEDs.
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This paper reports on the planning, introduction, and implementation of surface mount technology (SMT) for printed circuit board assembly at Convergent Technologies. It is written…
Abstract
This paper reports on the planning, introduction, and implementation of surface mount technology (SMT) for printed circuit board assembly at Convergent Technologies. It is written from the production personnel's view‐point. The report starts with a brief history of the company, describes its dynamic environment, outlines the factors that led to the decision to implement SMT and provides the time‐frame for said implementation. With this background the paper then deals at length with design and manufacturing issues and questions that arose during this undertaking. The report concludes with a summary that outlines the benefits and concerns of SMT and highlights the future trends for this technology.
Surface mounting technology is beginning to be used in commercial electronic products. This paper discusses the advantages of the technology and outlines the methods of assembly.
Damian Nowak, Andrzej Dziedzic, Zbigniew Żaluk, Henryk Roguszczak and Mariusz Węglarski
– The paper aims to investigate on the mechanical properties of surface-mount device (SMD) interconnections made on flexible and rigid substrates.
Abstract
Purpose
The paper aims to investigate on the mechanical properties of surface-mount device (SMD) interconnections made on flexible and rigid substrates.
Design/methodology/approach
The durability of joints to shear strength was measured with tensile machine. Investigations were carried out for 0402- and 0603-sized ceramic passives and integrated circuits in SOIC-8, TSSOP-8, XSON3 and XSON6 packages. Three types of flexible substrates (Kapton, Mylar and Pyralux) and two types of rigid substrates (LTCC and alumina) were used. SMD components were mounted with SAC solder or electrically conductive adhesive. Contact pads were made of Ag-based polymer paste on flexible substrates and PdAg-based cermet paste on ceramics. The shear strength was measured for as-made and long-term thermally aged test structures. The average durability and standard deviation were compared for different combination of materials. Moreover, mechanical properties of interconnections made of polymer thick-film pastes or electrically/thermally conductive adhesives between ceramic chips and flexible/ceramic substrates were investigated.
Findings
The mechanical properties of joints strongly depend on configuration of applied materials. Some of them exhibit high durability to shear strength, while other should not be recommended due to very weak connections. Additionally, long-term thermal ageing showed that exploitation of such connections at elevated temperature in some cases might increase their strength. However, for some materials, it leads to accelerated degradation of joints.
Originality/value
This paper provides practical information about SMD interconnections made with standard materials (lead-free solder, electrically/thermally conductive adhesives) and proposed non-standard procedures, e.g. assembling of ceramic chips with low temperature cermet or polymer thick-film conductive pastes.
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Muna E. Raypah, Mutharasu Devarajan and Fauziah Sulaiman
Proper thermal management is a key to improve the efficiency and reliability of light-emitting diodes (LEDs). This paper aims to report the influence of applying thermally…
Abstract
Purpose
Proper thermal management is a key to improve the efficiency and reliability of light-emitting diodes (LEDs). This paper aims to report the influence of applying thermally conductive materials on thermal performance of indium gallium aluminum phosphide (InGaAlP)-based thin-film surface-mounted device (SMD) LED.
Design/methodology/approach
The LED thermal and optical parameters were determined using the combination of thermal transient tester (T3Ster) and thermal and radiometric characterization of power LEDs (TeraLED) instruments. The LED was mounted on FR4, 2W and 5W aluminum (Al) package substrates. Measurements were carried out by setting different boundary conditions: air between LED package and substrate and using thermally conductive epoxy (TIM A) and adhesive (TIM B) of thermal conductivity 1.67 and 1.78 W/mK, respectively.
Findings
For LED mounted on FR4 package, the total real thermal resistance is improved because of TIM B by 6 and 9 per cent at 50 and 100 mA, respectively. Likewise, the relative decrease in total thermal resistance of LED on 2W Al package is about 9 and 11 per cent. As well, for LED mounted on 5W Al package, the total real thermal resistance is reduced by 2 and 4 per cent.
Originality/value
No much work can be found in the literature on thermal interface material effects on thermal performance of low-power SMD LED. This work can assist in thermal management of low-power LEDs.
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Muna E. Raypah, Dheepan M.K., Mutharasu Devarajan, Shanmugan Subramani and Fauziah Sulaiman
Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The…
Abstract
Purpose
Thermal behavior of light-emitting diode (LED) device under different operating conditions must be known to enhance its reliability and efficiency in various applications. The purpose of this study is to report the influence of input current and ambient temperature on thermal resistance of InGaAlP low-power surface-mount device (SMD) LED.
Design/methodology/approach
Thermal parameters of the LED were measured using thermal transient measurement via Thermal Transient Tester (T3Ster). The experimental results were validated using computational fluid dynamics (CFD) software.
Findings
As input current increases from 50 to 90 mA at 25°C, the relative increase in LED package (ΔRthJS) and total thermal resistance (ΔRthJA) is about 10 and 4 per cent, respectively. In addition, at 50 mA and ambient temperature from 25 to 65°C, the ΔRthJS and ΔRthJA are roughly 28 and 22 per cent, respectively. A good agreement between simulation and experiment results of junction temperature.
Originality/value
Most of previous studies have focused on thermal management of high-power LEDs. There were no studies on thermal analysis of low-power SMD LED so far. This work will help in predicting the thermal performance of low-power LEDs in solid-state lighting applications.
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This describes a new automated assembly technique, developed by Leica Geosystems and the Swiss Federal Institute of Technology, which allows the automated precision assembly of…
Abstract
Purpose
This describes a new automated assembly technique, developed by Leica Geosystems and the Swiss Federal Institute of Technology, which allows the automated precision assembly of miniature optical components and subsystems.
Design/methodology/approach
Dubbed TRIMO‐SMD (three‐dimensional miniaturised optical surface‐mounted device), this new technique is designed for use with optical components of around 2 mm in diameter such as laser diodes. It uses six‐axis robotic motion, automated optical alignment with cameras and position sensors and laser‐reflow soldering to assemble photonic modules.
Findings
This development has been commercialised and is being used in a production environment by Leica Geosystems. It fixes the optical element into position in just 2 s and the placement accuracy of each component is repeatable to within 1 μm.
Practical implications
This technique has allowed novel micro‐optical assemblies to be produced automatically and has improved the performance and reduced the size and weight of certain precision optical products such as laser rangefinders and Lidar transceiver modules.
Originality/value
This is a new technique which, by allowing the automated, precision assembly of miniature optical components, will benefit companies involved with the manufacture of optical sensing, telecommunications, medical and other products.
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The transition to surface mounted device (SMD) technology in electronics manufacturing has placed new demands on the post‐solder cleaning process. For spacecraft electronic…
Abstract
The transition to surface mounted device (SMD) technology in electronics manufacturing has placed new demands on the post‐solder cleaning process. For spacecraft electronic systems it is of the utmost importance that all flux residues be removed. This paper reports the results of an investigation of the impact of component stand‐off heights and the distance between solder joints on the cleaning process efficiency. The capability to clean beneath large chip carriers was evaluated for four different cleaning methods using isopropanol or CFC‐113 (Freon TMS) as cleaning liquid. The results show that the cleaning efficiency decreases considerably if the stand‐off height is less than 240 µm for 100 mil pitch chip carriers. For 50 mil pitch chip carriers the stand‐off height needs to be greater than 240 µm to achieve high cleaning efficiency. The cleaning efficiency beneath chip carriers with small stand‐off heights can be increased by using ultrasonic cleaning. However, a very thin layer of white residues is left where the flux has been removed if isopropanol is used as the cleaning liquid.