May 22, 2013 - We use under-fill under large BGAs. According to the under-fill material supplier, heating the component to just above T-liquidis of the solder, then twist/rotate and remove the component. Obviously the ...
Mike Gearhart, Novatel Wireless, USA
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May 20, 2013 - There are companies specialized in long-term storage. There are also companies specialized in re-plating the pins. So you can go external.
Moisture may be an issue for larger parts, that ...
Pieter Hoeben, Hoeben Electronics, Netherlands
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May 17, 2013 - Solderability performance of components are affected by oxidation under the storage environment. Possibly in one year time period. I would like to invite your comments as to how such large ...
Kazuyuki Hatada, An QA adviser, Japan
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May 16, 2013 - JEDEC released a publication just over a year ago regarding this topic, JEP160 - Long-Term Storage for Electronic Solid-State Wafers, Dice, and Devices. It is a good reference document. ...
Curtis Grosskopf, IBM, USA
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May 16, 2013 - I came across this issue about 25 years ago for micro-circuits which were being declared as "Life Time Buys" and no longer being manufactured. After performing a few experimental samples ...
Pete Phillips, Retired from Honeywell Int'l, USA
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May 8, 2013 - You missed a very big issue, the size of the placement tool. Even at 0603 you need to watch out as the outside edge of a tool extends past the ...
Bob Kondner, Index Designs, USA
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May 8, 2013 - As a number of responses have indicated the black material is silver sulfide and indicates that the environment has a source of sulfur which is most likely from the air. ...
George Brutchen, PE, EnerDel, Inc., USA
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May 8, 2013 - While in the Navy as a computer tech we saw a blacking of silver soldered components in out Magnetic Tape Unit. After extensive lab analysis it was found to be ...
Glenn Little, Amateur Radio WB4UIV, USA
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May 8, 2013 - So why is a poor fill a problem, particularly for electrolytic capacitors?
Low PTH fill will typically not disrupt normal operation, but may cause temperatures to elevate in the vicinity ...
Bhanu Sood, CALCE, University of Maryland, USA
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May 1, 2013 - I'd like to hear you discuss more the failure analysis aspect of the original question. You theorize that the gummy material is no-clean flux residue, and possibly a process indicator. ...
Alan C.,PSI, USA
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May 1, 2013 - We had similar problems regarding hole fill on a large assembly in a selective wave solder process and succeeded to achieve 80 to 100% solder fill. Due to time between ...
Frits Schoonbeek, Benchmark Electronics, Netherlands
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May 1, 2013 - You can order bare boards with solder paste pre-deposited/pre-fluxed. The bare boards will arrive ready-to-assemble right out of the box. No stenciling, no additional paste, just hand place and reflow. ...
Bob Lazzara, Circuit Connect, Inc., USA
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Apr 24, 2013 - Work closely with your printer and stencil suppliers. There are a variety of newer technologies that have been developed to deal with the increasing disparity between paste deposit sizes caused ...
Devo, XSYS, USA
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Apr 24, 2013 - There are software tools to help here, valor mss process preparation has one 'stencil optimizer'. It can calculate every aperture in a stencil based on link to cad package to ...
Joshua Lawson, Onboard Solutions, Australia
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Apr 24, 2013 - Not only component connections but even vias will be produced as plated hole. Trough hole vias are much less expensive than buried or blind vias because less procedures are required ...
Daniel Schoeni, ETH, Switzerland
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