We have separate geometries for those chip parts that are to be waved instead of
vapor phased. It has worked well.

______________________________ Reply Separator _________________________________
Subject: RE: ASSY:  0402 chip placement (#570929)
Author:  [log in to unmask] at SMTPpost1
Date:    10/9/96 3:55 PM


You might discover an increase in tombstoning components attributed to the 
amount of surface tension of the reflowed solder versus the relative weight 
of the component.  Often times one of the component pads may reflow a split 
second prior to the other pad, and the resulting surface tensions may shift/
and or tilt the component up.  These problems can be worked out by finding the 
proper combination of reflow process, and component pad geometry.  Some 
manufacturers seem to use component pads that are reduced at the component ends 
to help reduce the outward surface tension.  Good luck.
     
                                                          Steve A
     
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