We have a customer who is requesting that we use a reflow fixture consisting of a Durapol plate with removable tooling pins to accomodate several different large PWBs through the reflow process. These fixtures would run on the flat belt rather than edge rails and would require that we remove large (16"x12") fully loaded boards from the conveyor rails to install on these fixtures prior to reflow. Components on the board range include a number of BGAs and micro-BGAs.  The intent of the fixtures is to keep the board from flexing during reflow. My concern is that all the handling and flexing of boards with components in solder paste is going to increase the chances of soldering problems due to part separation from the paste if the board is flexed.

Question: Has anyone used this type of concept on large, densely populated boards. Comments on pros and cons? Any other insights would be appreciated as I'm looking for supporting evidence to dissuade them from this approach which is primarily aimed as saving fixture costs over dedicated SMT fixtures.

Thanks in advance.


Rick Thompson

Sr. SMT Process Engineer
SMTEK International, Inc.
+1 (805) 532-2800
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