Common Soldering Problems: Solder Bridge

What is a Solder Bridge?

Solder Bridges can be seen when two separate points on a circuit board is connected by the solder over the top of the PCB. This causes electrical short circuit which would in turn damage the circuit board and also injure those using the circuit board.

How are Solder Bridges formed?

This unintended connection of solder happens:

  • Excess solder use. Too much solder used will cause it to overflow to connect to surrounding pins. 
  • Gap in solder masks. Solder masks or solder resist coating are usually applied on the circuit board to protect areas that should not have solder. In rare cases, the solder mask may be improperly applied, causing gaps in the solder masks. 
  • A poor structure or design of the circuit board. Solder pads that are too big in relation to the gap between them, or the component to pad size ratio not providing sufficient space to solder can lead to the solder overflowing and touching other solder pads. 
  • Bad solder paste stencils. To speed up the soldering process, stencils are often used to quickly apply solder paste on intricate points. if the stencils were not cleaned between each application or if there is some damage to the stencil, it may lead to inaccurate application of solder paste which over-extends and lead to solder bridges. 

How to prevent Solder Bridge?

  • Use an appropriate amount of solder that is enough for the joint
  • Use the correct lead lengths for through-hole parts
  • Use the correct hole size and pad diameter for through-hole parts
  • Place fiducial marks on PCB
  • Ensure solder paste applied does not go beyond the designated placements.

How to fix Solder Bridge?

To repair the joint, follow according to these steps:

Step 1: Heat the tip of the soldering iron

Step 2: Use the soldering iron to melt the solder and cut through the connection thoroughly

Step 3: Create sufficient space and an appropriate distance between the 2 joints

Step 4: Use a solder-sucker to remove solder IF there is too much solder on the circuit board

Step 5: Use the iron to modify the joints if needed

 

12 most common soldering problems (and how to fix them):

  1. Cold Joint
  2. Disturbed Joint
  3. Overheated Joint
  4. Insufficient Wetting of the Surface Mount
  5. Insufficient Wetting of the Pad
  6. Insufficient Wetting of the Pin
  7. Solder Starved
  8. Too Much Solder
  9. Untrimmed Leads
  10. Solder Bridge
  11. Lifted Pad
  12. Stray Solder
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