I agree, you can check the variation by using pressure sensitive paper.

Others things worth checking are:
1. excessive wear / backlash in the drive between upper / lower rollers
(either chain or gears).
2. nicks / cuts in the rollers (operators with scalpels!)

Martin C


===== Original Message from [log in to unmask] (TechNet E-Mail Forum.) at
26/09/00 19:33
>A pressure variation from one end of the roller to the other would be my
>guess.
>Just had the same problem. Found one of the idler gears in the machine had
>spit out a key and was slightly out of alignment, which was causing the
>roller to apply uneven pressure across the panel.
>
>##############################################################
>TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
>##############################################################
>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
>##############################################################

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
##############################################################
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
##############################################################