While it may or may not be rejectable as a lifted pad defect, if it in fact
does not meet the specification for wrap plating (IPC-6012B Amendment 1
3.6.2.11.1), and by the photo's it does not, then it is still rejectable
under IPC-6012. If the quest here is for the root cause of the failure then
this may or may not be a factor but if it is simply to determine if the part
is rejectable then maybe we have the answer. Of further interest on the
subject of wrap plating is this article
http://www.pcb007.com/pages/zone.cgi?a=52739&_pf_=1 .
Regards,
John
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: March-14-13 8:19 AM
To: [log in to unmask]
Subject: Re: [TN] IPC-6012
Victor,
Sorry, I hit send earlier by mistake.
IPC-6012 is not very clear on LIFTED lands definition or requirement.
BUT MIL-PRF-55110 is.
Page 15 Para A.3.6.8
Page 50 Fig A-12.
According to the above this condition (even though not classical PTH) is not
rejectable. Maybe an issue long-term for your application.
And since this is "lifting with adhered base material"...I won't call it
workmanship issue right away either.
What I would look at
1) Materials choice for the application...maybe you need to use something
with better Z-axis expansion with Hole-fill matching the same.
2) How well the moisture is removed before you performed the thermal test?
Rush
Accurate Engg Inc
www.Accueng.com
818-768-3919
-----Original Message-----
From: Victor Hernandez <[log in to unmask]>
To: TechNet <[log in to unmask]>
Sent: Thu, Mar 14, 2013 5:44 am
Subject: Re: [TN] IPC-6012
Can someone quote chapter and verse if this is a rejectable anomaly. In
IPC-A-600F, "Non-Conforming - Class 1, 2, & 3 No lift allowed from the
laminate plane to the bottom surface at the end of the copper land, whether
or
not resin appears on the copper land off the board." Need judgment from
the
gurus as what that really mean and with photos to ensure the issue is well
understood.
Victor,
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Paul Reid
Sent: Thursday, March 14, 2013 7:25 AM
To: [log in to unmask]
Subject: Re: [TN] IPC-6012
Hi Vladimir,
What you have here is a lifted pad. I think that that is rejectable to 6012.
There appears to be an adiquate wrap of copper.
Best regards,
Paul Reid
________________________________
From: TechNet on behalf of Vladimir Igoshev. PhD
Sent: Wed 13/03/2013 5:18 PM
To: [log in to unmask]
Subject: [TN] IPC-6012
I have a question for boards gurus,
We run a set of tests to assess the workmanship of a PWB. The board had
vias-in-pad (in essence PTHs overplated with Cu pads) under a BGA.
After a thermal stress the pads were partially flitted due to cracked
laminated underneath them. To me it's a recipe for disaster (like pad
cratering after assembly). However, I saw nothing about it in
IPC-6012. Did I just miss it?
I'd really appreciate any contractive comments.
--
Best regards,
Vladimir Igoshev. PhD
mailto:[log in to unmask]
SENTEC Testing Laboratory Inc.
11 Canadian Road, Unit 7.
Scarborough, ON M1R 5G1
Tel: (416) 899-1882
Fax: (905) 882-8812
www.sentec.ca
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