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First, a short history of surface mount technology is given, followed by a section describing the current status of surface mount components and the impact of these on printed wiring boards. Then, two essential steps of SMT, component mounting and soldering, as practised in Japan, are discussed. The advantage of additive technology for SMT is briefly reviewed.

Low relative humidity (RH) effect surface mount devices in numerous ways. The smaller size (0201) capacitor and resistor start wasting when RH is low. Due to low RH, electrostatic charges built-up on the surface of surface mount devices (SMDs) and component’s reel. The positive charged SMDs stick with the negatively charged reel tape and are wasted. This paper comprehensively explores the environmental effects on 0201 size surface mount devices during mounting process. Different type and size of surface mount devices are tested in low and desired RH to validate the effectiveness of the proposed approach. This paper will also highlight high electrostatic discharge (ESD) due to low RH which can be detrimental for small size surface mount devices. The experimental and graphical illustrations will stipulate the results of success rate for mounting components. The effect on ESD, subsequently varying temperature and humidity will also be analyzed.

In this paper, 0201 SDMs will be considered for analysis. The surface mount technology (SMT) plant temperature and humidity has been varied to examine the properties of small size SMDs. Total 5 hours production data are collected from Laptop motherboard production environment. This approach is applicable to all SMT environment.

The authors reduced the wastage of 0201 chip size resistor and capacitor. Total 11 components are selected of this size, and there success rate is observed during mounting. These components are first observed in harsh environment where the temperature is first set to 20ºC and RH is set to 25 per cent. The success rate of these components is very low due to component’s wastage. When the plant temperature is set to 25ºC and RH is set to 45 per cent, the success rate of mounting increased up to 100 per cent. A single component placement success rate with respect to RH is observed for one month. The results are shown in Table IV. It can be seen that the success rate is near 100 per cent when RH and temperature is maintained in production environment. To eliminate the ESD build-up in material and equipment in manufacturing environment humidification is a very effective way. When the RH is kept to 45 per cent, the moisture content of the air is a natural conductor and earths any ESD in environment.

Experimental data have been obtained from Laptop motherboard manufacturing process to validate the effectiveness of proposed approach.

With the increased functional density requirements of military avionics it is impossible to meet these demands without utilising Surface Mount Technology. The Electronics Manufacturing Technology Group at Boeing Military Airplanes is working to meet SMT design requirements through research and development of processes, materials and equipment for all variations of SMT. Basic processes have been established for both 100% SMT and mixed technology. However, the Group continues to advance its capabilities by evaluating and improving all aspects of SMT manufacturing. A description of the initial thrust into Type III SMT as well as subsequent development is given. This includes a description of the evaluation of Surface Mount Component (SMC) attach adhesives comparing the adhesive used initially with others available by examining the various criteria involved in selecting the appropriate one for a given process. Also, a discussion follows of factors involved in determination of Mil‐spec. passive SMCs which are compatible with wave soldering. Included in the evaluation of passive SMCs is a comparison of the compatibility of the wave solder system in use with the component industry's recommended temperature profiles through an analysis based on in‐house testing to determine the actual component endurance to solder system heating. Throughout this discussion emphasis is placed on a systematic guided approach to examining process development.

Alpha Metals Ltd (UK) have announced the appointment of David Crimp to the position of General Manager. Having served the company for four years as Sales Manager, Mr Crimp now assumes complete responsibility for Alpha's entire UK operation. Prior to his appointment with Alpha Metals, he was employed by AMAX in both the UK and France.

The wearout characteristics were investigated for soldered interconnections of surface mount technology (SMT) chip resistors, chip capacitors and a 44 I/O ceramic leaded chip carrier (CLCC) package. Four double‐sided test vehicles were subjected to accelerated thermal cycling in the — 10°C to + 110°C range; 30°C/min ramp rate; and 1 minute dwell time at each temperature extreme. The test was interrupted at initially 500 cycle and later at 1000 cycle intervals to perform visual inspection of all soldered interconnections, functional performance verification for the test vehicles, and resistance measurement on leaded SMT joints. Metallographic examinations and fractographic studies were also performed after 0, 4500 and 13000 cycles to characterise the micromechanisms of soldered joint strength degradation and failure. The wearout thresholds for soldered joints of chip resistors and capacitors on side 1 were respectively 2500 and 4500 cycles. The greater thermal fatigue resistance of the latter joints was attributed to a lower device‐substrate coefficient of thermal expansion (CTE) mismatch and a more favourable device geometry compared with chip resistors. These passive components on side 2, however, showed a virtually identical soldered joint wearout threshold of 6500 cycles. The constraints imposed by the applied mounting adhesive were primarily responsible for this behaviour. No correlation appeared to exist among various failure criteria used to determine the onset of failure for leaded SMT soldered connections. The concurrent monitoring of electrical resistance and the applied tensile load showed a modest relationship between the load drop and resistance increase, however. The test vehicles continued to pass the functional performance verification, even after 13000 thermal cycles. Nonetheless, the joint wearout thresholds were considered to be 2500, 4500 and 4500 cycles for chip resistor, chip capacitor and CLCC components, respectively. A 50% soldered joint strength drop was considered as the wearout threshold for the CLCC device. Metallographic examination showed limited barrel wall cracking of the vias and no evidence of cracks with the through‐hole soldered joints, even after 13000 thermal cycles.

Present‐day electronics are shifting increasingly towards surface mounting technology (SMT) and hybrid technology (thick and thin film), which offer greater advantages due to their fabrication processes. Capacitors, like other components used in these processes, must occupy the smallest volume possible. Because of miniaturisation of the capacitors, the reliability of the surface mounting process is affected not only by the reliability of the components themselves but also by that of the assembly. In this study, a thermo‐mechanical simulation has been performed by means of ANSYS software based on the finite element method. This paper deals with the evaluation of a ceramic capacitor module (capacitors soldered on copper lands) on FR‐4 or alumina substrates during cooling to room temperature (25°C). The parameters of the assembly — temperature, length and thickness of the capacitor, thickness of the solder joint and nature of the substrate — were chosen by using the Design Of Experiments (DOE) method, which permits optimisation of these parameters and reduces the investigation time. The results showed a correlation between the length of the capacitor and the nature of the substrate used. Greater capacitor length is required for alumina substrate while a shorter length is preferred for FR‐4. It appears that a solder joint more than 100 urn thick may induce significant constraints on the copper lands and on the capacitor leads. It was noted that shear stress and voids in the solder joint can occur at temperatures higher than 250°C. This investigation makes it possible to prevent thermo‐mechanical stress damage during the mounting process and gives some recommendations for the choice of assembly variables.

The purpose of this paper is to develop a machine learning model that predicts the component self-alignment offsets along the length and width of the component and in the angular direction. To find the best performing model, various algorithms like random forest regressor (RFR), support vector regressor (SVR), neural networks (NN), gradient boost (GB) and K-nearest neighbors (KNN) were performed and analyzed. The models were implemented using input features, which can be categorized as solder paste volume, paste-pad offset, component-pad offset, angular offset and orientation.

Surface-mount technology (SMT) is the technology behind the production of printed circuit boards, which is used in several types of commercial equipment such as communication devices, home appliances, medical imaging systems and sensors. In SMT, components undergo movement known as self-alignment during the reflow process. Although self-alignment is used to decrease the misalignment, it may not work for smaller size chipsets. If the solder paste depositions are not well-aligned, the self-alignment might deteriorate the final alignment of the component.

It were trained on their targets. Results obtained by each method for each target variable were compared to find the algorithm that gives the best performance. It was found that RFR gives the best performance in case of predicting offsets along the length and width of the component, whereas SVR does so in case of predicting offsets in the angular direction. The scope of this study can be extended to developing this model further to predict defects that can occur during the reflow process. It could also be developed to be used for optimizing the placement process in SMT.

This paper proposes a predictive model that predicts the component self-alignment offsets along the length and width of component and in the angular direction. To find the best performing model, various algorithms like RFR, SVR, NN, GB and KNN were performed and analyzed for predicting the component self-alignment offsets. This helps to achieve the following research objectives: best machine learning model for prediction of component self-alignment offsets. This model can be used to optimize the mounting process in SMT, which reduces occurrences of defects and making the process more efficient.

Surface mount technology (SMT) is being increasingly used in printed circuit board (PCB) assembly. The reduced lead pitch of surface mount components coupled with their increased lead count and packing densities have made it imperative that automated placement methods be used. However, the SMT placement process is often a bottleneck in surface mount manufacturing. A reduction in placement time in SMT will enhance throughput and productivity. This paper describes the design and development of a prototype expert system based approach which identifies ‘near’ optimal placement sequences for surface mount PCBs in (almost) realtime. The software structure used integrates a knowledge based system with an optimisation module. PROLOG is the language used in this research. The system was rigorously validated and tested. Ideas for further research are also presented.

Implementing surface mount technology (SMT) into military systems has not progressed as rapidly as expected. One of the major reasons is the lack of availability of MIL Spec. surface mountable components. Therefore, if one is to realise the benefits of SMT, manufacturing processes must be developed that allow inserted components to be mounted on the same printed wiring board (PWB) with surface mount components (SMCs). Honeywell's Ordnance Division has developed manufacturing processes which allow SMCs to be mounted on both sides of the PWB and inserted components to be mounted on one side of the same PWB. The surface mount solder reflow and wave soldering are performed in a single‐step solder system. This simplifies and reduces the number of manufacturing process steps for this type of surface mount assembly (SMA). This paper describes three major types of SMAs and their complexity levels. Definitions of the SMA types and complexity levels are necessary for selecting production equipment and developing SMA processes. Assembly process limitations are directly related to the SMA type and complexity level. Layout guidelines and processes from solder deposition to cleaning are discussed. Full scale engineering development (FSED) hardware has been fabricated using the single‐step solder process for SMAs with both SMCs and inserted components on the same PWB. The single‐step solder process offers an excellent solution to fabricating electronic assemblies where SMCs and inserted components are mounted on the same PWB. Plans to expand and enhance the first generation SMA fabrication processes to accommodate higher complexity levels are discussed.

The popular reflow day was repeated at Henley and commenced with Mike Judd giving an overview of current reflow techniques.