[tinwhiskers] Re: New study on coating to mitigate whiskers
- From: engelmaier@xxxxxxx
- To: tinwhiskers@xxxxxxxxxxxxx
- Date: Fri, 15 May 2009 16:54:18 -0400
How can yo study something that is non-existent—"brains of the EU
politicians"? the good news, there is lots of room for growth.
Werner
-----Original Message-----
From: Norman Dancer <ndancer@xxxxxxxxxxxxxxxxxxx>
To: tinwhiskers@xxxxxxxxxxxxx <tinwhiskers@xxxxxxxxxxxxx>
Sent: Fri, 15 May 2009 4:43 pm
Subject: [tinwhiskers] Re: New study on coating to mitigate whiskers
Be
sure to test the brains of the EU politicians. They’ve definitely
got something growing there. J
(OK,
I’ll behave myself now).
From:
tinwhiskers-bounce@xxxxxxxxxxxxx [mailto:tinwhiskers-bounce@xxxxxxxxxxxxx] On
Behalf Of Fritz, Dennis D.
Sent: Friday, May 15, 2009 11:41 AM
To: tinwhiskers@xxxxxxxxxxxxx; tinwhiskers@xxxxxxxxxxxxx
Subject: [tinwhiskers] Re: New study on coating to mitigate whiskers
What is your whiskers inspection methodology?
I
am getting ready to do a study with Purdue undergraduate interns (who work for
a VERY attractive price for our program). We will determine
both the extent of whiskers growth on commercial boards - scrap cell phones and
laptops, and the ease of measurement by "semi-skilled"
operators. We will be using optical microscope, enhanced di
gital
microscope, and simple SEM.
Can
you share your proceedures?
Denny
Fritz
SAIC
- Merrillville, IN
From: tinwhiskers-bounce@xxxxxxxxxxxxx on behalf
of Jim Bunn
Sent: Fri 5/15/2009 10:55 AM
To: tinwhiskers@xxxxxxxxxxxxx
Subject: [tinwhiskers] Re: New study on coating to mitigate whiskers
I think they are
saying it works if the thickness is at least 2mils. Or maybe that the coating
is better than nothing.
We have a lot of uncoated stuff out there running a test right now. And it's
pretty comprensive considering the voltage levels that we are using in the
PCUs. I'm suprised that we have not had some kind of problem.
________________________________
From: tinwhiskers-bounce@xxxxxxxxxxxxx on behalf of Pedro Tort
Sent: Thu 5/14/2009 7:48 AM
To: tinwhiskers@xxxxxxxxxxxxx
Subject: [tinwhiskers] New study on coating to mitigate whiskers
The National Physics Laboratory in UK has undertaken a study on the capability
of different coatings to mitigate tin whiskers growth. The results of this
investigation reinforces the findings of Jay Bruse and Dr. Henning Leidecker
who back in 2007 found the Uralane 5750 Polyurethane was an effective
mitigation strategy for tin whiskers provided the nominal coating thickness was
2mils.
I quote from the first issue of the NPL Electronics Interconne
ction Newsletter:
"The use of conformal coatings is seen as the only practical means of
controlling whisker growths shorting adjacent conductors on a PCB. NPL has
studied three types of coating, to assess their effectiveness for inhibiting
whisker growth.
Two coatings, polyurethane and paraxylene both were found to reduce the growth
of whiskers for up to 150 days of testing, compared with failure of 14 days for
uncoated samples. The acrylic coating was found not to perform as well as the
others in parallel tests. All coatings failed to provide sufficient protection
in areas of insufficient coating coverage, at corners and sides of the test
samples."
Pedro Tort
Quality Manager
DigiProces, S.A.
Solsones, 87 - P.I. Pla de la Bruguera
P.O. Box 127
E-08211 CASTELLAR DEL VALLES
TEL. +34 937 142 132
FAX. +34 937 142 072
www.digiproces.com
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