Hello Ioan

I was previously advised by a coating manufacturer that the dyne measurement of solder resist should be >40.  I went through an exercise of evaluating various coatings to find the ones best suited for conformal coating and found that most matt solder resists achieve dyne >40, whereas gloss or semi-gloss resists were around 30 - 34 range. 

Regards

Mark

Mark Austin
Lead Engineer

Phoenix Systems UK Ltd

D: +44 1329 242325
T: +44 845 658 6111

 
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-----Original Message-----
From: TechNet <[log in to unmask]> On Behalf Of Ioan Tempea
Sent: Monday, March 11, 2024 7:42 PM
To: [log in to unmask]
Subject: [TN] Surface energy for conformal coating

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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