Reflow Soldering of Through-Hole Components Phil Zarrow, ITM, Inc. The rallying cry of manufacturing has been "do it cheaper, faster, better". Consequently there is a constant drive to reduce the cost of the product. After the cost of material, the cost of manufacturing is usually the most significant area contributor to product cost. The SMT manufacturing process is constantly being examined for ways of streamlining assembly. Aside from faster (and hopefully accurate) equipment, elimination of process steps is a practical approach to the enigma. Each process stop carries with it related capital costs for the equipment utilized as well as recurring costs for process material, support labor, equipment spare parts, and, of course, overhead such as floor space, power, and other utilities. In many cases, steps can sometimes be eliminated through incorporation of advanced SMT manufacturing methods. Bear in mind that alteration of the assembly process in such a manner will entail formal process development using designed experiments and statistical studies if the manufacturing process is indeed to be optimized.
Processing and Reliability of Low Cost Flip Chip Assemblies Implementing Fast-Flow, Snap-Cure Underfills byPaul N. Houston, Daniel F. Baldwin, Ph.D., Marnico Deladisrna, The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology,andLawrence N. Crane, Ph.D., Mark Konarski, Ph.D., Loctite Electronics Flip chip technology is finding increasing applications in the electronics manufacturing and packaging industries and continued growth is projected. Advances in flux and underfill materials will increase this growth provided the materials reduce manufacturing time and enhance yield and reliability. Fast-flow, snap-cure underfills are one of these new material sets. These underfills significantly reduce underfill flow times and lengthy dedicated cure cycles. One significant advantage is in double-sided board assembly applications where snap-cure underfills can be cured during the soak stage of a typical second side reflow cycle while the reflow spike forms the second side interconnects and also provides for additional curing This work presents a study of fast-flow, snap-cure underfill materials and a reliability assessment. The reliability of these materials are tested in air to air thermal cycling (-55�C to 125�C), liquid to liquid thermal shock (-55�C to 125�C) and J Standard 020 Level 3 Moisture Sensitivity Preconditioning prior to thermal cycling or thermal shock exposure. Comparisons are made between samples cured using a second reflow pass and samples cured in a standard batch oven at the underfill manufacturers' recommended cure schedule.
SMTnet.com Receives a Major Upgrade SMTnet.com has been upgraded once again, marking the first major change in the site's appearance in almost a year. In addition to an entirely new look, some new features have been added to the Electronics Forums, and other sections.
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Registered users will now find all of their Account Management information is accessible via a single link at the top and bottom of every page.
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Pages now fill the entire width of the screen, regardless of a user's screen resolution.
In addition to the aesthetic and functional changes, the back-end of the Web site has been upgraded as well. The site now runs entirely on SQL databases, allowing for more flexibility, and the Cold Fusion server software has also been updated.
This is a major upgrade that will improve the functionality and usefulness of the SMTnet Web site, making it an even more invaluable tool for the electronics manufacturing community.
Publish Your Papers and Promote Your Company As SMTnet prepares for the next issue of the SMT Express, we are looking to our readers for articles and papers to feature. Submissions will be accepted any time for future issues. If you have anything you wish to offer, such as papers you have written, book reviews, anecdotes, commentaries, or anything we haven't thought of, please send it to SMTnet. Also, please read the submission guidelines.
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SMTnet.com Receives a Major Upgrade
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