Visual inspection remains the dominant method of assessing component lead solderability and finished board solder joint quality. In recent years the wetting balance has received…
Abstract
Visual inspection remains the dominant method of assessing component lead solderability and finished board solder joint quality. In recent years the wetting balance has received much attention as an attractive alternative to the inherently subjective visual inspection method of assessing component termination solderability. Whether direct visual inspection or wetting balance methods are used, the method can be shown to be effective only if the results are in agreement with board‐level soldering performance. This paper addresses the issue of the agreement of visual board‐level solder joint quality with both visual ‘dip and look’ solderability assessment and wetting balance measurement of the components prior to board assembly. A description of visual ‘dip and look’ solderability test assessment and of wetting balance methodology for components is presented, and a compendium of wetting balance tests and indices are documented in the Appendix. The experimental strategy employed is outlined, and details of the experimental technique (including the equipment, materials and component sample preparations) are provided. The experimental results present a comparison of both ‘dip and look’ visual solderability assessment and wetting balance measures with regard to actual board‐level soldering performance. The ability of the various assessment methods to predict board level defects is also explored.
J.L. Marshall, D.E. Miiller, J. Sees, S.E. Matteson, D. Weathers and L. Lichtenberg
A combination of analytical methods was used on printed circuit board coupons to conclude the following: (1) while steam ageing deteriorates solderability of tinned coupons, it…
Abstract
A combination of analytical methods was used on printed circuit board coupons to conclude the following: (1) while steam ageing deteriorates solderability of tinned coupons, it does not increase the oxide thickness or tin‐lead ratio of the surface (top 50 Angstroms) of tinned coupons; (2) therefore, some other factor, probably oxidation of the copper or tin/copper intermetallic substrate, determines solderability of the coupons.
A significant number of integrated circuit (IC) package leads failing solderability tests also had a very thin eutectic solder coating. Poor solderability is attributed to…
Abstract
A significant number of integrated circuit (IC) package leads failing solderability tests also had a very thin eutectic solder coating. Poor solderability is attributed to degradation of this coating during various burn‐in times and temperatures. Techniques were developed to pre‐tin IC leads with lead‐rich solder (95Pb‐5Sn) as this finish had been reported in the literature to be particularly effective and superior to the eutectic composition in preserving solderability even after long ageing treatments. The present work has not confirmed those recommendations. In fact, surface analyses and various solderability tests performed on steam‐aged finishes demonstrate that 95Pb‐5Sn is not a viable alternative to 63Sn‐37Pb if standard spacecraft soldering practices are to be followed. Good solder wetting was always achieved if the artifically aged leads had a minimum eutectic coating thickness of 5–7 micrometres.
Sandra Healy, Michael Wallace and Eamonn Murphy
Market demands, especially within the automotive sector, are pushing towards increased product complexity and performance with zero ship parts per million (PPM) requirements. To…
Abstract
Purpose
Market demands, especially within the automotive sector, are pushing towards increased product complexity and performance with zero ship parts per million (PPM) requirements. To achieve both quality and performance goals very stringent requirements are being placed on the test manufacturing solution. These requirements lead to conflicts between cost, performance and quality. The purpose of this paper is twofold: first, to investigate the conflicts that exist between quality, performance, and cost, and second, to review current practices and techniques being used in tests to minimise ship PPM.
Design/methodology/approach
In the paper a test process development flow chart is presented, along with a review of current methods being used for both defect screening and performance testing. The relationship between test coverage and ship PPM is investigated using established yield models. The cost in terms of gross margin degradation of yield loss at final test to extensive screening and aggressive limits is modelled.
Findings
The paper finds that to maintain ship PPM very high levels of test coverage are required – typically test coverage needs to be > 98 per cent. The cost of yield loss to this testing typically matches on a percentage point basis gross margin degradation. Reviewing current test methods shows the need both for extensive defect‐screening techniques for the defective portion of the population, and for optimised guardbanding techniques for performance testing. Weaknesses that exist are the absence of a model to predict outgoing PPM, and the conservative nature of existing guardband techniques for performance testing.
Originality/value
This is a review paper and it serves to highlight both the weaknesses in current practices, and areas where improved models are required.
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Anh Tuan Nguyen and Nguyen Vang-Phuc Nguyen
The purpose of this paper is to identify the best practices of industrial engineering (IE) programs that could be learnt and used at other educational institutions.
Abstract
Purpose
The purpose of this paper is to identify the best practices of industrial engineering (IE) programs that could be learnt and used at other educational institutions.
Design/methodology/approach
Nine IE programs in the USA are benchmarked using a conceptual framework that considers an educational program as a system consisting of a purpose, a curriculum, resources, and quality processes. The information used in benchmarking is collected from the program self-study reports, course catalogs, and websites which are available on the internet.
Findings
It is found that in spite of their diversity in history, missions, sizes, and reputations, the studied programs are rather unified in terms of purpose definition, curriculum formation, resource selection, and quality process usage. From the analysis, a template of IE curriculum is proposed.
Research limitations/implications
As the selection of the studied programs is based on the availability of the information, the findings may not be representative for IE programs in the USA. Future work can aim at comparing IE programs from various countries.
Practical implications
The findings could be used as benchmarks by IE schools interested in the improvement of operations.
Originality/value
A conceptual framework for benchmarking is proposed and proves useful for comparing educational programs. The findings represent the current best practices at IE schools in the USA.
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As the world emerges from the COVID-19 global pandemic and medical emergency, the author looks at the impacts on the world of work and its management and also tries to set them in…
Abstract
Purpose
As the world emerges from the COVID-19 global pandemic and medical emergency, the author looks at the impacts on the world of work and its management and also tries to set them in some context. This study aims to discuss the aforementioned idea.
Design/methodology/approach
The author uses some of the latest global and comparative media and survey research as well as some theories to explore the topic of post-pandemic work and management.
Findings
Work – and its management – is impacted on by crisis, such as the pandemic, for twin inter-locking reasons. First, it engenders uncertainty, which comes in different degrees and levels and variability in people's comfortableness with it. Second, the commensurate jolt of a crisis can block existing models and force common experimentation, even in areas previously resisted, such as more flexible working patterns. There are a variety of short and longer term reasons for both changes to work and management and also responses and commitment to them by management and organisations.
Originality/value
The author details the impact of both the COVID-19 pandemic and wider contextual changes on the world of work. The author notes a set of reasons, both practical and theoretical, as to why flexible or hybrid working, while sometimes seen as a problem, can work. The author shows that rather than a simple “either-or” dichotomy in choice and support for post-pandemic work arrangements, there is a range of options.
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Sherri Sheinfeld Gorin and Patrick McAuliffe
The aims of this paper are to: briefly review the long‐term or late effects of cancer diagnosis and treatment on children and youth; examine the implications of these effects on…
Abstract
Purpose
The aims of this paper are to: briefly review the long‐term or late effects of cancer diagnosis and treatment on children and youth; examine the implications of these effects on the educational needs of the child or youth; explore the implications of childhood cancer survivorship on the school, particularly for female students. Over the last 25 years, treatments for childhood cancers have increased survival rates by 45 per cent, to nearly 77 per cent. It is estimated that one in 900 people aged 15‐44 years in the USA is a childhood cancer survivor; 80 per cent of children diagnosed with cancer in 1990 will survive into adulthood.
Design/methodology/approach
A comprehensive literature review of studies relevant to female childhood cancer survivorship and education over the past ten years was conducted, having been collected through searches of MEDLINE, CINAHL, PSYCINFO, and EMBASE.
Findings
Long‐term and late effects of cancer have been observed in neurocognition, cardiopulmonary symptoms, second cancers, reproductive organs, and hearing loss. Other health effects, such as impaired growth, osteopenia, hepatitis C infection, oral and dental malformations, and behavioral risk factors such as fatigue, obesity, and smoking have also been reported among childhood cancer survivors. These longer‐term treatment sequelae, particularly on neurological systems, have implications for changed student educational needs, including the provision of specialized instruction, classroom adaptations, as well as ancillary health services.
Research limitations/implications
Based on the ecologic model, a research agenda is proposed for better integrating the increasing numbers of childhood cancer survivors into the educational environment.
Practical implications
Practical interventions for survivors who are experiencing difficulties in school are listed.
Originality/value
To the best of one's knowledge, this is the first comprehensive review on the implications of childhood cancer survivors in schools.