Hi Joyce,
I see that nobody got the post I made earlier either. I can only
communicate by replying to the sparse emails that show up once in a blue
moon.
I've contacted the IPC and the IPC answers desk via email, but they don't
seem to want to be bothered with the Technet list anymore.
I find that strange because the listserver still keeps a history of
anything you post, it's just not sending it out to all of the members:
https://linkprotect.cudasvc.com/url?a=http%3a%2f%2flistserv.ipc.org%2fscripts%2fwa.exe%3fA1%3dind2403%26L%3dTECHNET%26X%3dOA7ABD561BF127A026B%26Y%3dsgregory%2540kimco.net&c=E,1,utptAhaahnaPvUVJLR_ma13_7CvTbhtHGOwBQ80J1sAA1enSMjAmaWiENIZPhaK93NioKAmSjJbOWHaLzrXYdhQ-Bij-zZM8iKroXZABn6x5&typo=1
It's too bad, I found over the years that Technet is a very valuable
resource. I guess they don't care anymore
Steve
On Wed, Mar 20, 2024 at 2:30 PM Joyce Koo <
[log in to unmask]> wrote:
> I didn't.
> jk ;-(
> > I got it Steve.
> >
> > Ioan
> >
> > De : Steve Gregory <[log in to unmask]>
> > Envoyé : March 20, 2024 8:49 AM
> > À : TechNet E-Mail Forum <[log in to unmask]>; Ioan Tempea
> > <[log in to unmask]>
> > Objet : Re: [TN] Surface energy for conformal coating
> >
> > Hi all,
> >
> > So I've seen Doug's reply and Ioan's reply. I'm going to reply and see if
> > anybody gets this...
> >
> > Steve
> >
> > On Wed, Mar 20, 2024 at 6:34 AM Ioan Tempea
> > <[log in to unmask]<mailto:
> [log in to unmask]>>
> > wrote:
> > Thanks Doug,
> >
> > Can't get it more thorough than that!
> >
> > We do have a Surface Analyst so I guess I'll request a side by side
> > dyne/contact angle characterization, to get the angle equivalents of 40+
> > dynes.
> >
> > Best regards,
> >
> > Ioan
> >
> > -----Message d'origine-----
> > De : TechNet <[log in to unmask]<mailto:[log in to unmask]>> De la part de
> > Pauls, Doug O Collins
> > Envoyé : March 20, 2024 8:18 AM
> > À : [log in to unmask]<mailto:[log in to unmask]>
> > Objet : Re: [TN] Surface energy for conformal coating
> >
> > You're welcome.
> >
> > Indiscrete Answers
> > - We will typically take surface energy readings when we qualify a new
> > board site, then monitor a few incoming lots, but often we do not test
> > again unless we have reason to go looking. The dyne pens, while
> > inexpensive and easy to use, are variable in interpretation. A more
> > accurate and repeatable measurement can be made with instruments designed
> > to measure surface tension and surface energy. There is one by Kruss,
> out
> > of Switzerland, and one from Brighton Science (formerly BTG Labs)
> (Surface
> > Analyst). We have both. Both work.
> > - Yes, manufacturing processes can impact surface energy. When we
> > qualify a site, we have a qualification vehicle fabricated by the
> > candidate site that then goes through our manufacturing processes. Then
> > we measure surface energy to see how much the manufacturing process
> > impacted the surface. We have some very robust cleaning processes, so
> we
> > seldom see the surface energy go down if the solder mask was fully cured
> > to start with.
> >
> > Douglas Pauls | Sr. Technical Fellow | Electronics AMT COLLINS AEROSPACE
> > 400 Collins Road NE, MS 108-101, Cedar Rapids, IA 52498 USA
> > Tel: +1 319 295 2109 | Mobile: +1 319 431 3773
> >
> > -----Original Message-----
> > From: TechNet <[log in to unmask]<mailto:[log in to unmask]>> On Behalf Of
> Ioan
> > Tempea
> > Sent: Wednesday, March 13, 2024 6:11 AM
> > To: [log in to unmask]<mailto:[log in to unmask]>
> > Subject: [External] Re: [TN] Surface energy for conformal coating
> >
> > Thanks Doug!
> >
> > Indiscreet questions:
> > - How do you make sure your spec is what you get? Do you request dyne
> > testing by the PCB fab?
> > - Do you measure dynes at Incoming or just in case you have issues on the
> > assembly line?
> > - Does surface energy variate during assembly? I mean a 40+ dynes/cm at
> > Incoming, will it stay the same after 2 reflows, some TH assembly,
> rework,
> > staking, etc., even with proper cleaning?
> >
> > Best regards,
> >
> > Ioan
> >
> > -----Message d'origine-----
> > De : TechNet <[log in to unmask]<mailto:[log in to unmask]>> De la part de
> > Pauls, Doug Collins Envoyé : March 12, 2024 10:03 PM À :
> > [log in to unmask]<mailto:[log in to unmask]> Objet : Re: [TN] Surface energy
> > for conformal coating
> >
> > Ioan,
> > In general, I have used this rule of thumb:
> > <30 dynes/cm - you will see problems with adhesion and wetting.
> > 30-35 dynes/cm - you will still see problems with adhesion and wetting,
> > but not as much as under 30.
> > 35-40 dynes/cm - generally decent adhesion and wetting but occasional
> > issues
> > 40+ dynes/cm - good adhesion and wetting. Collins specifies >44 dynes/cm
> > for its solder mask.
> >
> > Douglas Pauls | Sr. Technical Fellow | Electronics AMT COLLINS AEROSPACE
> > 400 Collins Road NE, MS 108-101, Cedar Rapids, IA 52498 USA
> > Tel: +1 319 295 2109 | Mobile: +1 319 431 3773
> >
> > -----Original Message-----
> > From: TechNet <[log in to unmask]<mailto:[log in to unmask]>> On Behalf Of
> Ioan
> > Tempea
> > Sent: Monday, March 11, 2024 2:42 PM
> > To: [log in to unmask]<mailto:[log in to unmask]>
> > Subject: [External] [TN] Surface energy for conformal coating
> >
> > Hello Technos,
> >
> > Some many years ago I have discovered, with help from this illustrious
> > panel, the existence of the dyne pens. Have used them for a while and
> them
> > moved to microelectronics, where I have spent 11 years without any
> contact
> > with conformal coating. So I've kinda forgot some details.
> > Where I work we have the Surface Analyst device, measuring contact angles
> > and this is supposed to obsolete the use of dyne pens.
> >
> > The trouble is I can't remember what dyne values are related to good
> > coating wetting. Or even better, which contact angles are preferred?
> >
> > Can anyone help?
> > I'm interested in both solder masked PCBs and Au plated ceramics and the
> > optimal values I believe differ from PCB to ceramics.
> >
> > Also, do you have any good articles or textbooks to recommend on this
> > matter?
> >
> > Thanks,
> >
> > Ioan
> >
> >
> > --
> > Steve Gregory
> > Kimco Design and Manufacturing
> > Process Engineer
> > (208) 322-0500 Ext. -3133
> > Cell Phone: (918) 706-2779
> >
> > [
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> >
>
--
Steve Gregory
Kimco Design and Manufacturing
Process Engineer
(208) 322-0500 Ext. -3133
Cell Phone: (918) 706-2779
--
This email and any attachments are only
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