Board positioning in the wave is crucial to avoid solder from covering components.

Flooding is a condition whereby solder “flows over,” thus causing the solder to flood on the component.

The primary assembly process setup areas to check:

• Board may be warped: need center support in the wave.
• Wave height too high.
• Conveyor too tight or too loose.
• Other things to look for in the assembly process:
• Solder temperature too high.
• Preheat too high.    
• Board not seated properly.
• Solder temperature too low.    
• Preheat too low.    
• Board rerun.
• Solder wave height high.    
• Conveyor speed high.    
• Defective fixture.
• Solder wave uneven.    
• Conveyor speed low.

Things to look for with the bare board fabrication:

• Board warped.    
• Things to look for with the board design:
• Poor pallet design.    
• Board size.    
• Weight distribution.