I got steve's post. https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fkimco.net&c=E,1,7nx7chTKr6cRWalef1EGT5qROT9nfoShuYpFMhC04CXjKV5k140bbIAl8W_TaEpctN4sa4vg5xO9zD9aqIA2YRNh7OrEH25We1kBanzNbSNKtAMkK5tzvTELmBo,&typo=1 host site blocked my reply because it is
hosted by google. See below. I guess google filter out some of the
emails deem to be "spam" risk. if I reply to technet, it will posted
because it is not direct from my IP address. I don't think TechNet can
fix the google filter issue.
fyi only.
jk
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550-5.7.1
likely unsolicited mail. To reduce the amount of spam sent to Gmail,
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end of DATA command)
> 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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>>
>
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