Grainy or Dull Solder Print E-mail
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Written by Paul Lotosky   
Monday, 01 March 2010 00:00

Contamination or poor heat are likely culprits.

Grainy or dull solder is defined as a rough solder surface with small, gritty projections protruding through the top, or a non-shiny surface that shows no signs of chemical attack.

  • Primary process setup areas to check:
  • Impurities in the solder.
  • Intermetallic compounds.
  • Dross mixed into the solder.
  • Insufficient heat.

Other things to look for in the process:

  • Solder temperature too low.     
  • Preheat too low.     
  • Early removal of board.
  • Solder contaminated.     
  • Conveyor speed high.     
  • Excessive solder dross.     
  • Conveyor vibration.

Fig 1


Other things to look for with the assembly:

  • Board contamination.    
  • Component contamination.    
  • Improper board handling.
  • Component leads too short.

Thing to look for with the bare board:

  • Board contamination.

Thing to look for with the board design:

  • Board contamination.  CA


Paul Lotosky is global director - customer technical support at Cookson Electronics
(; This e-mail address is being protected from spambots. You need JavaScript enabled to view it . His column appears monthly.

Last Updated on Tuesday, 09 March 2010 11:52


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