Schrodinger's? Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord Sent: Tuesday, June 18, 2013 2:12 PM To: [log in to unmask] Subject: Re: [TN] APEX Papers on Conformal coat and tin whiskers I am glad the whiskers in my nose isn't Tin. Imagine they grow and grow, and one day you look like a cat. Inge On 18 June 2013 12:00, Steven Creswick <[log in to unmask]> wrote: > Dewey > > Is this an e-mail link to a group or something? > > Steve C > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey > (EHCOE) > Sent: Tuesday, June 18, 2013 12:57 PM > To: [log in to unmask] > Subject: Re: [TN] APEX Papers on Conformal coat and tin whiskers > > Also try [log in to unmask] > Dewey > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Landman > Sent: Tuesday, June 18, 2013 9:50 AM > To: [log in to unmask] > Subject: Re: [TN] APEX Papers on Conformal coat and tin whiskers > > John Barnes is the person collecting the bibliography (> 20,000 > citations) > > * Bibliography for Tin Whiskers, Zinc Whiskers, Cadmium Whiskers, and > Other Conductive Metal Whiskers > http://www.dbicorporation.com/whiskbib.htm > > Bob Landman > > On Jun 18, 2013, at 5:52 AM, Steven Creswick > <[log in to unmask]> > wrote: > > > Inge, > > > > Sorry, but was not me. I can imagine there being a great deal of > > non-published work out there, however. > > > > Smooth skies! > > > > Steve C > > > > -----Original Message----- > > From: TechNet [mailto:[log in to unmask]] On Behalf Of Inge Hernefjord > > Sent: Tuesday, June 18, 2013 1:27 AM > > To: [log in to unmask] > > Subject: Re: [TN] APEX Papers on Conformal coat and tin whiskers > > > > FYI > > > > Someone (Trikeman?) told me that about 10,000 papers exist about > whiskers. > > Of course most of them are echoes. > > > > Inge > > > > > > On 12 June 2013 07:26, greg <[log in to unmask]> wrote: > > > >> There have been several papers published at APEX on the topic. But > >> whether they address the specific issues raised today I leave to > >> wiser heads than mine. > >> > >> APEX 2007: > >> > >> Effect of Conformal Coating on Tin Whisker Growth, Vijay Kumar and > >> Linda Woody, Lockheed Martin > >> > >> Parylene as a Suppressant for Tin Whiskers Growth on Printed > >> Circuit Boards, Rakesh Kumar Specialty Coating Systems > >> > >> Whisker Penetration into Conformal Coating, Stephen McKeown, Joseph > >> Kane, Dr. Stephan Meschter BAE Systems, Johnson City, NY > >> > >> > >> APEX 2008: > >> > >> Effects of Tin Mitigation Processes on Whisker Growth and Solder > >> Joint Reliability for Chip and Small-Outline Package Components, > >> Tom Lesniewski and Tom Higley, Northrop Grumman Network > >> Communications, San Diego, CA 92128 > >> > >> APEX 2010: > >> > >> Conformal Coatings for Tin Whisker Risk Management, William Fox and > >> Linda Woody Lockheed Martin Missiles and Fire Control, Ocala, > >> Florida > >> > >> > >> And Chris Hunt did publish also but the APEX papers of his do not > >> talk about conformal coating. (He may have published somewhere else > >> on whiskers/coatings. Dave who published on tin coated braided wire > >> may want to weigh in after he returns.) > >> > >> Having done the file search on the above whiskers/coatings APEX > >> papers and read their summaries the answer to "Does it help?" seems > >> (to me) to be somewhere between "yes/no/maybe/it depends." (i.e. > >> it's "above my pay > >> grade.") > >> > >> Greg Munie > >> IPC Director of Design Programs > >> > >> > >>> -------Original Message------- > >>> From: Mike Fenner <[log in to unmask]> > >>> To: [log in to unmask] > >>> Subject: Re: [TN] minimum thickness of Type UR Conformal coat and > >>> tin > >> whiskers > >>> Sent: 12 Jun '13 09:07 > >>> > >>> Richard, slightly tongue in cheek I ask: How does soldering with > >> tin/lead > >>> prevent tin finish on PCB whiskering? > >>> > >>> Phil I recall Chris Hunt of NPL in UK did some work on this. You > >>> can probably download a copy of paper from their WWW. > >>> > >>> Best Wishes > >>> > >>> > >>> > >>> Mike > >>> > >>> > >>> > >>> -----Original Message----- > >>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D. > >>> Sent: Wednesday, June 12, 2013 2:22 PM > >>> To: [log in to unmask] > >>> Subject: Re: [TN] minimum thickness of Type UR Conformal coat and > >>> tin whiskers > >>> > >>> Not only can the whiskers grow through the conformal coating, they > >>> can > >> grow > >>> under it like weeds in a stream. NASA has some good pictures of > >>> this on their website. > >>> The best tin whisker mitigation scheme is called tin/lead solder. > >>> > >>> -----Original Message----- > >>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls > >>> Sent: Wednesday, June 12, 2013 8:10 AM > >>> To: [log in to unmask] > >>> Subject: Re: [TN] minimum thickness of Type UR Conformal coat and > >>> tin whiskers > >>> > >>> Phil, > >>> While this is an answer I "should" know, I don't. Dave Hillman > >> regularly > >>> attends and presents at the CALCE yearly conference on whiskers > >>> and so > >> he > >>> keeps up on all of that. At present, my esteemed colleague is > >>> bumping > >> his > >>> head on rocks, kayaking upside down, on some white water in North > >> Carolina. > >>> He should be back in the office on Monday and will no doubt answer > > then. > >>> > >>> From our discussions, the general rule is still "no conformal > >>> coating prevents whiskers". A thicker coating may cause the > >>> whisker to expend > >> more > >>> energy punching through and yet more energy to punch through an > >>> adjacent coating on a lead (usually resulting in buckling), but I > >>> have yet to > >> hear > >>> about some magic thickness of any kind of coating that completely > >> mitigates > >>> whiskers. But I could be wrong. > >>> > >>> Dave? > >>> > >>> Doug Pauls > >>> > >>> > >>> > >>> From: Phil Bavaro <[log in to unmask]> > >>> To: <[log in to unmask]> > >>> Date: 06/11/2013 02:26 PM > >>> Subject: [TN] minimum thickness of Type UR Conformal coat and > > tin > >>> whiskers > >>> Sent by: TechNet <[log in to unmask]> > >>> > >>> > >>> > >>> Doug et al, > >>> > >>> Is there a disagreement in the industry as to what minimum > >>> thickness of urethane is required in order to mitigate tin > >>> whisker > > concerns? > >>> > >>> I am hearing that the .003+/-.002" does not provide enough of a minimum > >>> thickness and that the number is as high as .004". I can understand > >>> wanting the minimum being raised to .002" but higher than that > >>> would > >> seem to > >>> make the process much more difficult to control. > >>> > >>> I have a potential customer asking if we measure the thickness on > >>> the individual component leads which is another can of worms it > >>> seems. We always used flat samples to document our thicknesses. > >>> > >>> I did not get to attend this years APEX so I might have missed the > >> latest > >>> data. > >>> ________________________________ > >>> This message and any attachments are solely for the use of the > >>> addressee and may contain L-3 proprietary information that may > >>> also be defined as > >> USG > >>> export controlled technical data. 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