Comments on: Managing Whiskers – Both Tin and Facial http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/ by Cirexx Internatinoal Tue, 27 Jul 2010 10:49:38 -0700 http://wordpress.org/?v=2.8.4 hourly 1 By: Bruce http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-1293 Bruce Wed, 19 May 2010 14:45:32 +0000 http://www.cirexx.com/blog/?p=692#comment-1293 So conformal coating cannot be well controlled. I suggest to coat a number of boards, measure the resultant coating thickness, then proceed with the experiment. If a board coating is TOO thin, run it through again. The resultant graph would feature thickness on one graph axis, and propensity to grow whiskers on the other. Non-uniform coating thickness would not be an issue. A cursory googling on the term "conformal coating thickness gauge" produced lots of hits, including this one: http://www.defelsko.com/applications/conformal.htm. So conformal coating cannot be well controlled. I suggest to coat a number of boards, measure the resultant coating thickness, then proceed with the experiment. If a board coating is TOO thin, run it through again. The resultant graph would feature thickness on one graph axis, and propensity to grow whiskers on the other. Non-uniform coating thickness would not be an issue.

A cursory googling on the term “conformal coating thickness gauge” produced lots of hits, including this one: http://www.defelsko.com/applications/conformal.htm.

]]> By: Amadeo Isart http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-994 Amadeo Isart Fri, 16 Apr 2010 13:37:00 +0000 http://www.cirexx.com/blog/?p=692#comment-994 The use of Sn-Bi alloy has proven to be rather effective in avoiding tin whiskers. I have seen internal reports from two major defense contractors (sorry no names, NDA's in place)that will be using Bismuth at 2%. You also might be interested in checking the following report among the many you can Google out. http://www.welwyn-tt.com/downloads/pbfree/sn-whisker-report.pdf The use of Sn-Bi alloy has proven to be rather effective in avoiding tin whiskers. I have seen internal reports from two major defense contractors (sorry no names, NDA’s in place)that will be using Bismuth at 2%.
You also might be interested in checking the following report among the many you can Google out.

http://www.welwyn-tt.com/downloads/pbfree/sn-whisker-report.pdf

]]> By: Otto J Hunt http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-911 Otto J Hunt Tue, 23 Mar 2010 17:08:45 +0000 http://www.cirexx.com/blog/?p=692#comment-911 So conformal coating cannot be well controlled. I suggest to coat a number of boards, measure the resultant coating thickness, then proceed with the experiment. If a board coating is TOO thin, run it through again. The resultant graph would feature thickness on one graph axis, and propensity to grow whiskers on the other. Non-uniform coating thickness would not be an issue. A cursory googling on the term "conformal coating thickness gauge" produced lots of hits, including this one: http://www.defelsko.com/applications/conformal.htm. So conformal coating cannot be well controlled. I suggest to coat a number of boards, measure the resultant coating thickness, then proceed with the experiment. If a board coating is TOO thin, run it through again. The resultant graph would feature thickness on one graph axis, and propensity to grow whiskers on the other. Non-uniform coating thickness would not be an issue.

A cursory googling on the term “conformal coating thickness gauge” produced lots of hits, including this one: http://www.defelsko.com/applications/conformal.htm.

]]> By: Loretta Kish http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-893 Loretta Kish Sat, 20 Mar 2010 13:46:37 +0000 http://www.cirexx.com/blog/?p=692#comment-893 Conformal coating is not a prosess that is easy to control! You would have to make multiple passes through the machine for thickness, that is if the contract manufacture has one. Some CM's use a spray can. Conformal coating is not a prosess that is easy to control! You would have to make multiple passes through the machine for thickness, that is if the contract manufacture has one. Some CM’s use a spray can.

]]> By: Otto J Hunt http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-887 Otto J Hunt Fri, 19 Mar 2010 15:48:43 +0000 http://www.cirexx.com/blog/?p=692#comment-887 I understand that conformal coat suppresses whisker formation, but it has to be thick. I would like to see a study that establishes a curve of coating thickness on one axis, and probability of whisker growth on the other. I understand that conformal coat suppresses whisker formation, but it has to be thick. I would like to see a study that establishes a curve of coating thickness on one axis, and probability of whisker growth on the other.

]]> By: Loretta Kish http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-837 Loretta Kish Mon, 08 Mar 2010 15:57:53 +0000 http://www.cirexx.com/blog/?p=692#comment-837 I certainly hope the committee on Energy and Commerce understand that the RoHos Directive could be the issue causing "Tin Whiskers! I always used 63%tin/37%lead for decades. Now take the lead out,which was added to stop Tin Whiskers! I certainly hope the committee on Energy and Commerce understand that the RoHos Directive could be the issue causing “Tin Whiskers!

I always used 63%tin/37%lead for decades. Now take the lead out,which was added to stop Tin Whiskers!

]]> By: Loretta Kish http://www.cirexx.com/blog/2010/03/managing-whiskers-tin-facial/comment-page-1/#comment-836 Loretta Kish Mon, 08 Mar 2010 15:51:32 +0000 http://www.cirexx.com/blog/?p=692#comment-836 This is where I would start a Six Sigma Project! This is where I would start a Six Sigma Project!

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