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 <[log in to unmask]>: host aspmx.l.google.com[172.253.62.26] said: 550-5.7.1 [208.65.246.140 12] Gmail has detected that this message is 550-5.7.1 likely unsolicited mail. To reduce the amount of spam sent to Gmail, 550-5.7.1 this message has been blocked. For more information, go to 550 5.7.1 https://support.google.com/mail/?p=UnsolicitedMessageError c22-20020a05620a269600b0078a2fff5023si252461qkp.210 - gsmtp (in reply to 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 >> >> [https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fkimco.net%2fEmailLogos%2fKDMsig200.png&c=E,1,0APBNUk0JMqSWmGtbQ-2dgP4NS89V7fk5PB3LC6-K_ea5qcPK8EohtSXRw3aowB6LulGdhRY0tALvdEN2gAJdwTx4K7DstOXuQCKkuHbu349PYjoZg,,&typo=1] >> This email and any attachments are only for use by the intended >> recipient(s) and may contain legally privileged, confidential, >> proprietary >> or otherwise private information. Any unauthorized use, reproduction, >> dissemination, distribution or other disclosure of the contents of this >> e-mail or its attachments is strictly prohibited. If you have received >> this email in error, please notify the sender immediately and delete the >> original. >> >