P. McCluskey, R. Munamarty and M. Pecht
Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptanceas potentially the lowest cost packages for high pin count applications. The main factors for…
Abstract
Plastic ball grid arrays (PBGAs) have been gaining increasing industry acceptance as potentially the lowest cost packages for high pin count applications. The main factors for their success include the inherent low cost of plastic packages, the high yields achievable with existing assembly equipment, the density advantages of an area array and, in many cases, superior electrical performance. The reliability of these packages with respect to solder joint fatigue has been extensively studied; however, little has been published on their reliability with respect to moisture‐related failure mechanisms during assembly, such as popcorning. In this study, two types of plastic ball grid array packages, a 225‐lead full matrix array and a 256‐lead perimeter array, which were preconditioned by baking at 125°C for 24 hours followed by exposure to 85°C and 30% relative humidity for 168 hours, were then subjected to three passes of simulated infra‐red reflow at 1°C/s and 0.67°C/s. Subsequent examination using scanning acoustic microscopy and environmental scanning electron microscopy revealed considerable delamination and cracking in both package types reflowed at the higher ramp rate. This damage originated in the die attach and propagated along the weakest interfaces in the package. At the lower ramp rate, a much smaller amount of delamination was observed. This suggests that there is a critical ramp rate below which popcorn cracking can be inhibited.
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R. Munamarty, P. McCluskey, M. Pecht and L. Yip
Two types of Plastic ball Grid array packages, a225‐lead full matrix array and a 256‐lead perimeter array, were subjected to 168 hours of moisturepreconditioning at 85°C and 30…
Abstract
Two types of Plastic ball Grid array packages, a 225‐lead full matrix array and a 256‐lead perimeter array, were subjected to 168 hours of moisture preconditioning at 85°C and 30% relative humidity followed by simulated infra‐red reflow at temperature ramp rates of 1°C/s and 0.67°C/s. The packages were subsequently examined for delamination and cracking using scanning acoustic microscopy and environmental scanning electron microscopy. At the higher ramp rate, delamination and cracking were observed in both package types, originating in the die attach and propagating along the weakest interfaces. At the lower ramp rate, a small amount of delamination was observed. This suggests that there is a critical ramp rate below which popcorn cracking does not occur.
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M. Wickham and C.P. Hunt
A survey of rework practices of the UK electronics assembly industry has been undertaken. Rework of electronics components in the UK was found to be dominated by the use of…
Abstract
A survey of rework practices of the UK electronics assembly industry has been undertaken. Rework of electronics components in the UK was found to be dominated by the use of soldering irons. Many companies did not control tip temperatures, rework times, background heating or the number of rework operations which could be undertaken on any one component. Few companies followed the recommendations of the component manufacturers aimed at preventing damage to thermally sensitive components. It was found that those companies which did control rework temperatures, did reduce rework temperatures for surface mount components. In general, rework temperatures were much higher than those recommended by the component manufacturers. A great deal of cleaning was undertaken after rework, with most companies doing some form of local cleaning. Most companies reused components even if only on an occasional basis.
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Javad Barabady, Tore Markeset and Uday Kumar
The purpose of this paper is to review, discuss and further develop the production assurance (PA) concept; and to define and describe a typical production assurance program (PAP…
Abstract
Purpose
The purpose of this paper is to review, discuss and further develop the production assurance (PA) concept; and to define and describe a typical production assurance program (PAP) and its elements.
Design/methodology/approach
An explorative literature study covering PA and dependability concept was carried out on contemporary literature. During the course of the study, meetings and discussions with a number of experts in Sweden and Norway were performed. Different types of data and examples from the oil and gas industries are used to illustrate and support the discussions.
Findings
This paper indicates that the concept of PA helps the decision maker to estimate whether a production plant is able to meet customer requirements, as it provides information about the production plant's delivery capacity, production rate and ability to deliver according to design or customer demands. PAP can provide a basis for effective production control.
Research limitations/implications
The material analysed was mainly related to the oil and gas industry. However, the findings and discussion can be transferred to other areas of application, such as mine production plants and chemical process plants.
Practical implications
A PAP is a valuable tool for production plant managers and engineers, not only for documenting a production plant's performance, but also for providing decision support for the development and optimization of the production plant to improve the plant's performance and reduce risk and uncertainties.
Originality/value
In this paper the concept of dependability is extended to include capacity performance and customer requirements or market demand, which provides a measure for delivery assurance or plant production performance in relation to customer requirements. This paper also develops a generic PAP to achieve a high level of delivery assurance.
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N. Geren, M. Çakirca and M. Bayramoğlu
To design a flexible integrated robotic assembly and rework (remanufacturing) cell for assembly, selective assembly and rework of advanced surface mount components (SMCs) using…
Abstract
Purpose
To design a flexible integrated robotic assembly and rework (remanufacturing) cell for assembly, selective assembly and rework of advanced surface mount components (SMCs) using the generic methodology developed in this paper.
Design/methodology/approach
Manual rework procedures are investigated for all advanced SMCs. General and specific component‐related rework considerations are obtained and necessary tooling candidates for automation are determined. This is followed by determination of the specific automated rework procedure and selection of suitable tooling for automated robotic rework and generation and evaluation of design concepts.
Findings
The developed methodology, which considers the reflow tool at the centre of the development process, has worked well in designing a flexible integrated robotic assembly and rework cell.
Practical implications
This study identified the rework requirements for advanced SMCs, the essential features for rework reflow tools, criteria for comparing reflow tools, and a generic procedure for design and concept selection.
Originality/value
It provides valuable knowledge for designers of flexible integrated robotic assembly and rework cells for assembly, selective assembly and rework of advanced SMCs.
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Ji Hyuck Yang and Kang Yong Lee
To apply the design of experiments (DOE) methodology to the problem of cracking of plastic ball grid array (PBGA) packages during the reflow soldering process.
Abstract
Purpose
To apply the design of experiments (DOE) methodology to the problem of cracking of plastic ball grid array (PBGA) packages during the reflow soldering process.
Design/methodology/approach
The DOE methodology was used in order to identify the optimum design. CAE was used for the required stress analysis and for integral calculation during crack analysis.
Findings
The optimum design to reduce the stress and fracture probability for the PBGA package was obtained and the DOE technique was shown to be very powerful for establishing the optimum design when there are many design parameters.
Research limitations/implications
In future research, a robust design methodology could be applied including design for six sigma considering the noise parameters.
Practical implications
For better design of a PBGA package, the DOE methodology has been shown to be very useful.
Originality/value
In this paper, application of the DOE approach to a PBGA package design in order to reduce the stresses and probability of fracture was attempted for the first time.
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Necdet Geren, Çağdaş Sarıgül and Melih Bayramoğlu
The purpose of this paper is to apply the developed systematic mechanical design methodologies, that are obtained in part I, to investigate their success in designing mechanics of…
Abstract
Purpose
The purpose of this paper is to apply the developed systematic mechanical design methodologies, that are obtained in part I, to investigate their success in designing mechanics of a flexible printed circuit board assembly (PCBA) rework cell.
Design/methodology/approach
The decision of soldering and desoldering tool, which is the most critical function of a PCBA rework or remanufacturing cell, significantly influences overall design concept. Therefore, the paper starts by applying the design methodology to the soldering and desoldering function. The same study is repeated for the rest of the sub‐functions but only the results are provided.
Findings
An application of rework machine design methodology for the design of a PCBA rework cell has been made available. In addition to this, the embedded knowledge, such as the requirements list, the function structure, the function/means tree, the weighted objective tree and evaluation chart for the soldering and desoldering function are provided.
Practical implications
The paper is the first work providing both embedded knowledge and the application of the systematic design methodology for the design of a fully automated flexible PCBA rework cell. The methodology leads rework machine designers in a well‐controlled and structured design environment.
Originality/value
The design methodology can be applied to all functions or targeted on key weighted areas to ensure that the designed rework machine meets the key areas of concerns. Furthermore, the methodology is generic and may be used to develop other complex manufacturing sytems.
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M. Dube, T.J. Dishongh, K.E. Beatty and M. Pecht
Temperature measurements using thermocouples are made at several locations on J‐leaded plastic quad‐flat packs and printed wiring boards during the reflow soldering process. Both…
Abstract
Temperature measurements using thermocouples are made at several locations on J‐leaded plastic quad‐flat packs and printed wiring boards during the reflow soldering process. Both moisture saturated and dry packages are studied, with little difference found in the measured temperature on the package surfaces. The temperature at the component lead is found to be a good approximation to the temperatures observed near the die. This provides an externally measurable parameter to assess delamination and popcorning.