Ed, here is the status of the data from the ITRI registration report.  Basically I would consider the report to be in a peer review stage.  The specifications that are impacted by this report would be the IPC-6011 and 6012 performance specifications and the IPC-D-275 for design.  Copies of the report have been provided to a number of the committee members.  ITRI has not had the opportunity to make a presentation to the group yet.

The purpose of this peer review is two fold.  It gives wider exposure to the test data gathered by the study, and allows experts manufacturing a wide range of product with a wide range of reliability needs to review the data and the recommendations made in the report.  This process would be the same whether it is ITRI, the October project, Company X or Y, etc.  Concensus from this meeting could be: to affect immediate specification change; recommend additional work to be done;  or to reject all recommendations.

My informal opinion is that the data will have some impact on the IPC specifications.  In the ITRI report, the group concluded that there were some areas that additional work was necessary.  I believe that between ITRI and the specifications task groups a clear concensus as to the path forward will be achieved.

If individuals are interested in staying on top of this issue, I would encourage them to get involved with IPC's design standard and performance specifications task group.

Thanks for the question Ed.

Best Regards


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>>> Ed Cosper <[log in to unmask]> 08/22/97 04:28PM >>>
I read the response below with great interest as this has always been a serious concern regarding manufacturing tolerances. So, I have a question for IPC.  If this report is supported by factual data ( Which I must assume it is.. )  will IPC change current annular ring requirements?

I addressed to Technet since I don't know who to specifically send it to at IPC.

Regards,

Ed Cosper

----------
From:  David Arivett[SMTP:[log in to unmask]]
Sent:  Friday, August 22, 1997 3:52 PM
To:  [log in to unmask]
Subject:  Re: [TECHNET] Annular Ring Limits

Chris,

  ITRI (The Interconnect Technology Research Institute) recently published a
report that addresses your concerns. In essence they found that a PTH
without annular ring is as reliable as a pad with a large annular ring.
Samples were submitted from several PWB manufacturers and the thermal cycle
testing was performed by NIST or Crane. Any way I'm sure you can get the
report either from ITRI in Austin, Texas or from the IPC

David Arivett
Cuplex Inc.

At 01:24 PM 8/22/97 -0500, you wrote:
>Seeking data/reports to address questions on the risks associated with
>Annular Ring size.  In particular, as the mis-registration of the of the
>mechanical drill to the PTH Pad moves towards a trace leading into the pad
>the potential for an 'open' to occur increases.  Concerns center around
>'thin' ring passing ET, but in field stresses cause fracture and crack
>propagation to 'open' state.
>
>Thanks, Chris
>
>