To All;

The IPC Small Hole Round Robin was released in the later part of 1988. It
covered holes with aspect ratios from 5:1 to 9:1. Still, there are questions,
by a number of us, as to whether another one needs to be run. Yes, processes
have changed, for the better. However, not all board shops have their
processes up to the latest developments. 
Therefore, the design committee still cautions designers about the effects of
high aspect ratio holes and the plated copper walls. 

Perhaps a new study will reveal that the problem is gone, throughout the
industry.

Regards,

Gary Ferrari
Tech Circuits
Chairman - IPC Design Committee
(203) 269-3311