Hello Jack - we have had good success with perimeter heating via 4 
     independent nozzles on 20 and 25 mil pitch parts using nitrogen. We 
     did have to do a considerable amount of process characterization for 
     our pwa population but the system works well.
     
     
     
     Dave Hillman
     Rockwell Collins
     [log in to unmask]
     


______________________________ Reply Separator _________________________________
Subject: Assy: Semi-Auto Fine Pitch Rework Machines
Author:  [log in to unmask] at ccmgw1
Date:    4/19/96 2:15 PM


     
I am investing in a fine pitch rework station for low volume placement and 
rework of .020 in. c-c PQFP parts.  I am interested in users experience with 
variable perimeter heating vs nozzle heating.  Which type of heating have 
you had the better results using? Any other related comments would be 
appreciated.
     
Thanks,
Jack Tippit
Wilcox Electric
[log in to unmask]