John Lau, Dongkai Shangguan, Todd Castello, Rob Horsley, Joe Smetana, Nick Hoo, Walter Dauksher, Dave Love, Irv Menis and Bob Sullivan
Failure analyses of the lead‐free and SnPb solder joints of high‐density packages such as the plastic ball grid array and the ceramic column grid array soldered on SnCu hot‐air…
Abstract
Failure analyses of the lead‐free and SnPb solder joints of high‐density packages such as the plastic ball grid array and the ceramic column grid array soldered on SnCu hot‐air solder levelling electroless nickel‐immersion gold or NiAu, and organic solderability preservative Entek printed circuit boards are presented. Emphasis is placed on determining the failure locations, failure modes, and intermetallic compound composition for these high‐density packages' solder joints after they have been through 7,500 cycles of temperature cycling. The present results will be compared with those obtained from temperature cycling and finite element analysis.
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John Lau, Walter Dauksher, Joe Smetana, Rob Horsley, Dongkai Shangguan, Todd Castello, Irv Menis, Dave Love and Bob Sullivan
The lead‐free solder joint reliability of several printed circuit board mounted high‐density packages, when subjected to temperature cycling was investigated by finite element…
Abstract
The lead‐free solder joint reliability of several printed circuit board mounted high‐density packages, when subjected to temperature cycling was investigated by finite element modelling. The packages were a 256‐pin plastic ball grid array (PBGA), a 388‐pin PBGA, and a 1657‐pin ceramic column grid array. Emphasis was placed on the determination of the creep responses (e.g. stress, strain, and strain energy density) of the lead‐free solder joints of these packages.
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Joe Smetana, Rob Horsley, John Lau, Ken Snowdon, Dongkai Shangguan, Jerry Gleason, Irv Memis, Dave Love, Walter Dauksher and Bob Sullivan
The High Density Packaging Users Group conducted a substantial study of the solder joint reliability of high‐density packages using lead‐free solder. The design, material, and…
Abstract
The High Density Packaging Users Group conducted a substantial study of the solder joint reliability of high‐density packages using lead‐free solder. The design, material, and assembly process aspects of the project are addressed in this paper. The components studied include many surface mount technology package types, various lead, and printed circuit board finishes and paste‐in‐hole assembly.
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John Lau, Nick Hoo, Rob Horsley, Joe Smetana, Dongkai Shangguan, Walter Dauksher, Dave Love, Irv Menis and Bob Sullivan
Temperature cycling tests, and statistical analysis of the results, for various high‐density packages on printed‐circuit boards with Sn‐Cu hot‐air solder levelling, electroless…
Abstract
Temperature cycling tests, and statistical analysis of the results, for various high‐density packages on printed‐circuit boards with Sn‐Cu hot‐air solder levelling, electroless nickel‐immersion gold, and organic solder preservative finishes are investigated in this study. Emphasis is placed on the determination of the life distribution and reliability of the lead‐free solder joints of these high‐density package assemblies while they are subjected to temperature cycling conditions. A data acquisition system, the relevant failure criterion, and the data extraction method will be presented and examined. The life test data are best fitted to the Weibull distribution. Also, the sample mean, population mean, sample characteristic life, true characteristic life, sample Weibull slope, and true Weibull slope for some of the high‐density packages are provided and discussed. Furthermore, the relationship between the reliability and the confidence limits for a life distribution is established. Finally, the confidence levels for comparing the quality (mean life) of lead‐free solder joints of high‐density packages are determined.
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Jade Danielle Hope and Faye Kathryn Horsley
Most individuals regularly encounter fire, but certain uses are legally disallowed. Horsley (2020, 2021; in press) proposed the continuum of fire use theory (CoFUT), which posits…
Abstract
Purpose
Most individuals regularly encounter fire, but certain uses are legally disallowed. Horsley (2020, 2021; in press) proposed the continuum of fire use theory (CoFUT), which posits that the legitimacy of fire use exists on a spectrum. This study aims to investigate the CoFUT and to elucidate the process of conceptualising legitimacy in a sample of legitimate fire users.
Design/methodology/approach
A sample of 16 legitimate fire users underwent semi-structured interviews regarding their own experiences with fire, the factors considered when determining the legitimacy of fire use and the relationships between those factors. The data extracted was subjected to conceptual analysis.
Findings
Analysis indicated that the legitimacy of fire use is best conceptualised along a continuum. Placement on the continuum required consideration of seven defining attributes: function; location; scale; materials used; characteristics of the actor(s); potential and actual consequences, and social acceptance. These attributes were shown to have interactive semantic relationships with one another.
Practical implications
A continuum approach to understanding fire use is a novel conceptualisation. Exposing the nuances that exist along the continuum could inform early intervention strategies aimed at fostering healthy relationships between young people and fire. Furthermore, practitioners working with arsonists would benefit from adopting a continuum perspective that allows for consideration of offenders’ individualised trajectory “up and down” the continuum of fire use.
Originality/value
Findings offer support for the CoFUT (2020; 2021; in press) and provide insight into how the legitimacy of fire use is conceptualised in legitimate fire users.
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President, Charles S. Goldman, M.P.; Chairman, Charles Bathurst, M.P.; Vice‐Presidents: Christopher Addison, M.D., M.P., Waldorf Astor, M.P., Charles Bathurst, M.P., Hilaire…
Abstract
President, Charles S. Goldman, M.P.; Chairman, Charles Bathurst, M.P.; Vice‐Presidents: Christopher Addison, M.D., M.P., Waldorf Astor, M.P., Charles Bathurst, M.P., Hilaire Belloc, Ralph D. Blumenfeld, Lord Blyth, J.P., Colonel Charles E. Cassal, V.D., F.I.C., the Bishop of Chichester, Sir Arthur H. Church, K.C.V.O., M.A., D.Sc., F.R.S., Sir Wm. Earnshaw Cooper, C.I.E., E. Crawshay‐Williams, M.P., Sir Anderson Critchett, Bart., C.V.O., F.R.C.S.E., William Ewart, M.D., F.R.C.P., Lieut.‐Colonel Sir Joseph Fayrer, Bart., M.A., M.D., Sir Alfred D. Fripp, K.C.V.O., C.B., M.B., M.S., Sir Harold Harmsworth, Bart., Arnold F. Hills, Sir Victor Horsley, M.D., F.R.C.S., F.R.S., O. Gutekunst, Sir H. Seymour King, K.C.I.E., M.A., the Duke of Manchester, P.C., Professor Sir Wm. Osler, Bart., M.D., F.R.S., Sir Gilbert Parker, D.C.L., M.P., Sir Wm. Ramsay, K.C.B., LL.D., M.D., F.R.S., Harrington Sainsbury, M.D., F.R.C.P., W. G. Savage, M.D., B.Sc., R. H. Scanes Spicer, M.D., M.R.C.S., the Hon. Lionel Walrond, M.P., Hugh Walsham, M.D., F.R.C.P., Harvey W. Wiley, M.D., Evelyn Wrench.