Solder Voids or Outgassing Print E-mail
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Written by Paul Lotosky   
Thursday, 03 September 2009 18:22

Call them blowholes or pin holes. Just don’t call them often.

Where the solder joint has a small, visible hole that penetrates from the surface of a solder connectionWave Trouble Icon between the conductive patterns on internal layers, external layers or both of a board is known as a solder void. This is typically due to moisture entrapment that, during the soldering process, outgassed from the joint.

Primary process setup areas to check:

  • Topside or overall board temperature too low, entrapping moisture that is out-gassed at the wave.
  • Entrapped fluid by component in through-hole.
  • Chemical contaminants not removed during fabrication process.
  • Contamination in the hole.
  • Topside of the hole covered by component body or flashing.

Other conditions to look for in the process:

  • Solder temp too high.
  • Preheat too low.
  • Insufficient flux blow-off.
  • Solder temp too low.
  • Contaminated flux.
  • Board pallet too hot.
  • Flux applied unevenly.
  • Flux SP GR too low.
  • Conveyor speed high.
  • Solder wave height low.
  • Flux SP GR too high.
  • Conveyor speed low.
  • Solder wave uneven.
  • Flux not making contact.
  • Board not seated properly.    

Other conditions to look for with the assembly:

  • Board contamination.
  • Component contamination.
  • Improper board handling.

Things to look for with fabrication:

  • Board oxidized.
  • Defective mask material.
  • Board warped.
  • Board contaminated.
  • Moisture in the laminate.
  • Poor plating in the hole.
  • Mask in hole.
  • Hole and pad misregistered.
  • Misregistration of the mask.

Things to look for with the board design:

  • Lead-to-hole ratio too large.
  • Internal ground plane.
  • Component orientation.
  • Lead-to-hole ratio too small.


Figure 1

Paul Lotosky is global director - customer technical support at Cookson Electronics (cooksonelectronics.com) This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Last Updated on Wednesday, 09 September 2009 18:42
 

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