We have always taken the interpretation that the narrowest feature can have isolated reductions down to 80% of the minimum specified on the drawing. All other widths we allow 30% reduction of the existing width. We are comfortable with this since a overall 20% of the master is allowed and additional 20% isolated reductions are acceptable. This requirement was developed from IPC-FC-250 table 8 which allows 35% reduction from the master width.
##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8c
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in
the body:
To subscribe: SUBSCRIBE TECHNET <your full name>
To unsubscribe: SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################