Same blocks that you had encountered the anomaly on.  For example, a
Blind Via B Block that has a barrel condition thought to be from
preparation required that 2 other samples be assessed from that same
feature type.

Jeffrey Bush
Director, Quality Assurance and Technical Support

VERMONT CIRCUITS INCORPORATED
  76 Technology Drive - POB 1890
    Brattleboro, Vermont 05302
      Voice: 802.257.4571.21 Fax: 802.257.0011
           http://www.vtcircuits.com
 
-----Original Message-----
From: Kerry Bode [mailto:[log in to unmask]] 
Sent: Friday, March 04, 2005 9:50 AM
To: [log in to unmask]
Subject: [TN] Interpretation of IPC6012A 4.2.2

As stated in IPC-6012 A section: 4.2.2 Referee Test: "Two additional
micro-
section sets from the same panel may be prepared and evaluated for
micro-
section defects that are considered to be isolated or random in nature
or
caused by micro-section preparation. For acceptance, both referee sets
must be defect free"   What is the interpretation of "Two additional
micro-
section sets"? Is it limited to the micro-section plating structure in
which the defect was detected. My thoughts are based upon IPC-6012A
Table
4-3 Acceptance Testing and Frequency. The table identifies the frequency
of micro-section evaluation based on PWB designs with a signal plating
structure. Does this table represent a micro-section set. As noted in.
IPC-
6012A section 3.6 Structural Integrity states "Blind and Buried vias
shall
meet the requirements of plated-through holes." This sentence requires
redeployment of table 4-3 for each additional plating structure within
the
PWB as a set.

For example: If a micro-section evaluation revealed low copper in one of
the 9 different plating structure it would be have no bearing on the
other
8 plating structures. The referee sections would only be relevant to the
set structure the defect was detected in. The example can be applied to
many attributes; however in each case the deficiency must be isolated or
random. With that said: What is the interpretation of micro-section set?


Thanks
Kerry

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