Looking at the correspondance on this, there seem to have been two
different definitions of what is a supported hole and what is an
unsupported hole. One definition talks of plated barrels and unplated
barrels, while the other definition talks of pads - one or none for
unsupported and two for supported. Majority rule goes with the plating
definition (my own understanding of the difference between supported and
unsupported holes), but I am interested to know the origins of and resons
for two such different definitions. Anyone have a light they can shed on
this?

Peter



"Mcmaster, Michael" <[log in to unmask]>  26/06/2002 08:14 AM
Sent by: TechNet <[log in to unmask]>

Please respond to "TechNet E-Mail Forum."; Please respond to "Mcmaster,
Michael"

              To:  [log in to unmask]
              cc:  (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
              Subject: Re: [TN] Definition of Supported/ unsupported hole








So if it's unplated, why does an unsupported hole have a breakout (or more
appropriately a "no breakout") requirement (IPC-6012 Table 3-5)?


      ----------
      From:   Neda Thrash[SMTP:[log in to unmask]]
      Reply To:       TechNet E-Mail Forum.;Neda Thrash
      Sent:   Tuesday, June 25, 2002 1:36 PM
      To:     [log in to unmask]
      Subject:        Re: [TN] Definition of Suported/ unsupported hole


      Peter, a supported hole in a PWB is plated through the board
      according to IPC-T-50 (Terms and Definitions for Interconnecting and
      Packaging Electronic Circuits) " or otherwise reinforced". The
      unsupported holes do not contain plating.


      >>> [log in to unmask] 06/25/02 02:22PM >>>
      Technet,


      Can anyone explain the difference between a supported
      and unsupported hole on PCB?


      I am reading a section on IPC-A-600 RevF and section
      2.10.3/4 specify difference acceptance criteria
      according to the hole type.


      Rgds,
      Peter


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