I have seen a similar problem when laminating dry film products on our vacuum 
laminator.  Mostly on photo coverlay (for Flex) and primary resist.  We call it 
pre tack, which means the film as attached itself to the surface before the 
actual lamination.  When the process cycle proceeds the entire film is pulled 
toward the area of "pre tack" leaving this circular wrinkle.

Ask your self:  Is the panel to hot?
                Did something or somebody apply unwanted, early pressure to that
                spot?
                Does the mask need to be suspended over the panel?

Good luck

Chuck Brummer
[log in to unmask]



______________________________ Reply Separator _________________________________
Subject: FAB, soldermask lamination
Author:  [log in to unmask] at ccUnix
Date:    2/20/97 11:36 AM


Hello Technet,
We have been experiencing problems with our soldermask lamination process.  We 
use Dupont's Vacrel 8140 dry film soldermask, and apply with an EH2400 vacuum 
laminator.  Upon removal from the laminator, we frequently see that rings have 
formed in the soldermask.  The rim of the ring is darker green, and the area 
confined by the ring is lighter green than the surrounding soldermask.  We 
have requested help/suggestions from mfg of both laminator and film, but as 
often happens, each says the problem is not with their product.
Has anyone else experienced this problem while vacuum laminating dry film 
soldermask?  Any suggestions on how to eliminate this problem would be greatly 
appreciated.
cbh

*************************************************************************** 
* TechNet mail list is provided as a service by IPC using SmartList v3.05 * 
*************************************************************************** 
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   * 
* with <subject: subscribe/unsubscribe> and no text in the body.          * 
*************************************************************************** 
* If you are having a problem with the IPC TechNet forum please contact   * 
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      * 
***************************************************************************


***************************************************************************
* TechNet mail list is provided as a service by IPC using SmartList v3.05 *
***************************************************************************
* To subscribe/unsubscribe send a message <to: [log in to unmask]>   *
* with <subject: subscribe/unsubscribe> and no text in the body.          *
***************************************************************************
* If you are having a problem with the IPC TechNet forum please contact   *
* Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask]      *
***************************************************************************