> ----------
> From:         Geoff Layhe
> Sent:         12 June 2000 09:47
> To:   [log in to unmask]
> Subject:      RE: [TN] Wrinkles in copper foil
>
> Jan,
> Just a few quick thoughts on wrinkled copper.
>
> It can be due to different expansion rates of the material on either side
> of the copper, i.e. the laminate and the separator plates. If this is your
> problem it will usually be worse on high layer count boards, in the middle
> of a stack and on larger panel sizes.
> Try different separator plates, aluminium may work better than steel, use
> a release film in contact with the copper, or release coated aluminium
> separators this will allow the copper to expand and contract easier.
>
> Have you tried a lower pressure?
>
> Is your copper foil tooled? if so does the wrinkling occur around the
> tooling holes? Maybe the tooling holes are not quite in the the right
> position or are too tight on the copper and the copper has to be
> "stretched" on them.
>
> Hope the ideas help
>
> Geoff Layhe
> www.lamar-uk.co.uk.
>       ----------
>       From:   Jan Thuesen[SMTP:[log in to unmask]]
>       Reply To:       [log in to unmask]
>       Sent:   09 June 2000 10:33
>       To:     [log in to unmask]
>       Subject:        [TN] Wrinkles in copper foil
>
>       Dear Technetters,
>       we have been seeing increasingly problems with wrinkles in
> outerlayer copper foil on certain jobs.
>       The wrinkles are coming from the press-lamination of multilayers.
>
>       We have tried different things to minimize the problem like
> optimising heat up and cool down time and temperature, different types of
> presspads, awareness at lay up, adding copper areas to the underlying
> layers, different prepregstyles amo.
>
>       If any of you have some additional inputs to the cause of the
> problems, we will be very interested in hearing from you.
>
>       With best regards
>
>       Jan Thuesen
>
>       ##############################################################
>       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
>       ##############################################################
>
>

##############################################################
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
##############################################################