HOW THICK IS THE BOARD?
IS THERE A LOT OF COPPER IN THE BOARD?
DOES YOUR CUSTOMERS PROVIDE HEAT RELIEF IN THE BOARDS BARREL DESIGN
THERE NEEDS TO BE PLENTY OF ROOM FOR LEADFREE SOLDER TO FLOW, DID YOU CHECK YOUR PIN(LEAD)TO HOLE (BARREL) RATIO?
NO PREHEATER, CAN YOU PRE-BAKE YOUR BOARDS? BE CAREFUL OF OTHER COMPONENTS
THICKER BOARDS (THICKER THAN .062") WITH HEAVY GROUND PLANE ARE CHALLENGING PREHEAT AND TO FLUX.
IS THE FLUX FILLING THE BARREL?
TAKE A BARE BOARD OR THE SOLDER SAMPLE OF THE BOARD, WITHOUT PARTS. PLACE A SHEET OF PAPER ON THE TOPSIDE, RUN THE BOARD THROUGH THE FLUXING/SOLDERING PROCESS THEN CHECK THE PAPER. THE PAPER SHOULD BE WET WITH FLUX LETTING YOU KNOW YOUR SPRAY FLUXER WORKS WELL AND FLUX IS MAKING IT TO THE TOP OF THE BARREL
ANOTHER WAY TO CHECK IS TO APPLY A DROP OR TWO OF FLUX FROM THE TOPSIDE INTO THE BARRELS IF THE SOLDERING IMPROVES YOUR SPRAY FLUXER COULD BE THE ISSUE
DROPPING CONNECTOR PINS, I THINK IT COULD BE RELATED TO TOO LONG OF A DWELL TIME OVER HEAT
I HOPE THIS HELPS :)
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