It is interesting that the crack also cracked through the legend ink. I suspect this happened after PWB fab. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Thayer, Wayne - IIW Sent: Thursday, March 22, 2012 10:32 AM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask Be nice to figure out what caused the cracking, since that would give an indication as to whether the underlying laminate is at risk. But solder mask's job is to prevent solder wetting, and a cracked mask can still do a fine job with that. Matter of fact, I often don't even put mask down in places which don't need it to block solder flow (like across a dielectric which won't wet anyway). Solder mask is not intended as an electrical insulator (yes, I wear that t-shirt regularly). If the cracks mean that the soldermask is poorly cured or poorly adhered, then it probably won't block solder well, so it may be no good. But your pictures are of reflowed boards, so who really cares whether it has mask covering dielectric or not? Moisture ingress blocking has been brought up, but I doubt soldermasks, which are typically loaded with completely acceptable pinholes AND have generous clearances around pads, are much use there anyway. Wayne Thayer -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey Sent: Thursday, March 22, 2012 12:04 PM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask You looking at pate 10-46 in revE? Cracking of Solder mask: A1, A2, D3. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben Sent: Wednesday, March 21, 2012 3:39 PM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask Bill, Looking again at your images, you could say that the cracks don't actually bridge non-common circuits since you have non-solder mask defined pads - the crack ends before it reaches another circuit. Ben -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Gumpert, Ben Sent: Wednesday, March 21, 2012 3:30 PM To: [log in to unmask] Subject: Re: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask Bill, I see the confusion; 610 mentions a target condition for cracks, but then doesn't follow up with an acceptable or defect condition for cracks. But later in the document, a solder mask scratch that bridges non-common circuits is indicated as a defect for all classes, so I would have to say a crack bridging non-common circuits is also a defect for all classes. Ben -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of William Clark Sent: Wednesday, March 21, 2012 3:03 PM To: [log in to unmask] Subject: EXTERNAL: [TN] Acceptability of Cracked Solder Mask It is not clear to me from IPC 610-E if a crack in a solder mask constitutes a Class 1 or Class 2 defect. Pictures of the typical cracks we are seeing are at the link below. The crack in picture 3 repeats at the same feature on every board in the array. The cracks were not visible on the bare board and the boards passed the tape test. I'm looking for input on the suitability of these boards. Thanks Bill http://s1066.photobucket.com/albums/u408/clarkerg/ Bill Clark Manufacturing Engineering and Quality Manager ERG, <http://www.ergpower.com/> Inc. 2601 Wayne Street, Endicott, NY 13760 607-754-9187 ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ ______________________________________________________________________ This email has been scanned by the Symantec Email Security.cloud service. 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