Thanks for your input.
Suitability was the wrong choice of words. I was looking for the answer to
the question of IPC defect or not. Our designers ignore the dielectric
properties of the mask. I was reminded that in the event of a conflict I
should use the words in the IPC standard, not the picture. I find figure
10-109 to be in conflict with the words next to 10-116 as the cracks shown
in 10-109 connect non common circuits. I find no conflict in the words
that have led to the following conclusion for our particular application.
If there is a crack adjacent to a trace that does not connect with a non
common trace it is not a defect. If there is a crack that communicates with
a non common trace it is a defect.
There are certainly other considerations relative the boards fabrication,
moisture and life issues.
Thanks again.
Bill
Bill Clark
Manufacturing Engineering and Quality Manager
ERG, Inc. 2601 Wayne Street, Endicott, NY 13760
607-754-9187
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: Thursday, March 22, 2012 12:39 PM
To: [log in to unmask]
Subject: Re: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask
One a possible cause.
There are a couple of questions in my mind:
Has the mask performed its role in achieving form fit and function?
Is the anomaly and indication that some other condition may exist? In other
words, was the board subject to conditions that might have caused some less
visible condition that reduces the product life in its service environment.
Committee consensus: A1, A2, D3.
Your mileage may vary, Guy.
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Thursday, March 22, 2012 12:08 PM
To: [log in to unmask]; [log in to unmask]
Cc: [log in to unmask]
Subject: RE: [TN] EXTERNAL: [TN] Acceptability of Cracked Solder Mask
Moisture ingression point to the laminate.
Victor,
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Guy Ramsey
Sent: Thursday, March 22, 2012 11:04 AM
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
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