Ed,
In your study, make note of whether the surface you are testing rested
against any packing material (like polyethylene shrink wrap) or interleave
material (like paper or Silver Saver). I have found that boards from the
center of the pack of boards can sometimes have different energy than
those that are at the top or bottom.
Doug Pauls
From: Ed Popielarski <[log in to unmask]>
To: <[log in to unmask]>
Date: 02/12/2014 09:57 AM
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal
Coating Adhesion
Sent by: TechNet <[log in to unmask]>
I'm launching a study here to try to correlate variation in soldermask
surface activity measured with Dyne Pens vs. "spotty" defects we see from
time to time. My theory is that the "out of the box" surface activity may
be marginal in some cases, and wetting problems exacerbated by
environmental (handling, atmosphere, etc.) influences that would have
negligible effect if the activity were otherwise better.
I've selected 5 Dyne "classes" as a sorting mechanism, 46+, 42+, 36+,30+,
30- and will test one board per "batch", i.e., P/N & Job No. & record
measured value. I will have inspection scrutinize for dewetted spots and
advise before touchup so I can record the defect in its appropriate entry.
I'll let y'all know if there are any interesting results.
Ed Popielarski
Engineering Manager
970 NE 21st Ct.
Oak Harbor, Wa. 98277
Ph: 360-675-1322
Fx: 206-624-0695
Cl: 949-581-6601
https://maps.google.com/maps/myplaces?hl=en&ll=48.315753,-122.643578&spn=0.011188,0.033023&ctz=420&t=m&z=16&iwloc=A
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Braddock, Iain (UK)
Sent: Wednesday, February 12, 2014 7:41 AM
To: [log in to unmask]
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal Coating
Adhesion
Doug,
Hmm....now why did I not think of that?
The trouble is I am working on a special project that requires expensive
complicated processing so I was hoping to steal a lead from someone with
experience in this area - not being one for reinventing the wheel.
Iain
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: 12 February 2014 13:39
To: TechNet E-Mail Forum; Braddock, Iain (UK)
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal Coating
Adhesion
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Iain, quite simple. Start with a bad level for the material then improve
it until it is not bad anymore. That will be your good level.
I love being helpful.
Doug Pauls
From: "Braddock, Iain (UK)" <[log in to unmask]<
mailto:[log in to unmask]>>
To: <[log in to unmask]<mailto:[log in to unmask]>>
Date: 02/12/2014 04:24 AM
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal
Coating Adhesion
Sent by: TechNet <[log in to unmask]<mailto:[log in to unmask]>>
________________________________
Hi all,
On the Dyne pens theme, does anyone had an idea what would be a good value
for a Taconic TLY3 double sided laminate that has had one side of Cu
etched away.
Regards,
Iain
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of GRIVON Arnaud
Sent: 11 February 2014 08:05
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal Coating
Adhesion
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Hello,
Thank you for the clear information provided.
As a supplement, I would be interested in someone could give the reference
of the mentioned ASTM standard for surface energy measurement by Dyne
Pens.
Also wondering why there is no IPC standard or guideline on this topic, as
conformal coating adhesion on solder mask is a quite common concern within
the industry.
It looks like indications given by Doug are acknowledged as good practice
and therefore could be introduced within IPC standards.
Best regards,
Arnaud Grivon
-----Message d'origine-----
De : TechNet [mailto:[log in to unmask]] De la part de Lee Hitchens Envoyé :
mardi 4 février 2014 07:26 À : [log in to unmask]<mailto:[log in to unmask]>
Objet : Re: [TN] [COM] Solder Mask Surface Tension for Conformal Coating
Adhesion
Hi Arnaud
I agree with Doug on this on using Dyne Pens although with no clean
processing generally you are lucky if you can get close to the range of
35-40! We tend to be working in the lower range of this.
It's also solder resist / coating dependent. Don't dismiss the energy
value out of hand immediately. There is no logic sometimes to selection.
We found one case where we tried absolutely any coating we could find to
stick to a solder resist and only one did. No idea why and none of the
chemists could explain.
Best Regards
Lee Hitchens
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Douglas Pauls
Sent: 03 February 2014 17:01
To: [log in to unmask]<mailto:[log in to unmask]>
Subject: Re: [TN] [COM] Solder Mask Surface Tension for Conformal Coating
Adhesion
Arnaud,
I think you are asking about surface energy rather than surface tension.
We use the readily available Dyne Pens which have solutions calibrated
back to an ASTM standard.
I generally use this rule of thumb regardless of the coating used.
Under 30 dynes/cm: Coating adhesion will be poor
30-35 dynes/cm: Coating adhesion will be slightly better, but you can
expect more frequent cases of delamination.
35-40 dynes/cm: Coating adhesion generally good, but can have some
periodic delamination or adhesion issues.
40-45 dynes/cm: Coating adhesion is good and only rarely will you see
delamination problems
45+ dynes.cm: Good adhesion.
Of course, there will always be special cases but this is a good starting
point.
Doug Pauls
From: GRIVON Arnaud <[log in to unmask]<
mailto:[log in to unmask]>>
To: <[log in to unmask]<mailto:[log in to unmask]>>
Date: 02/03/2014 10:48 AM
Subject: [TN] [COM] Solder Mask Surface Tension for Conformal
Coating Adhesion
Sent by: TechNet <[log in to unmask]<mailto:[log in to unmask]>>
Hello TechNet,
I would like to sense the best practices in terms of solder mask surface
tension with respect to conformal coating adhesion :
- Which standard/test method are you using?
- Which requirement (e.g. minimum value in dyn/cm²) would you
accept for the various CC types (acrylics, urethanes, silicone, parylene)?
Thanks in advance for the insights.
Best regards,
Arnaud Grivon
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