When PCB soldering components are on a printed circuit board, you may encounter cases of solder bridging. Solder bridging takes place the moment two solder joints connect. When the two solder joints connect, they form an undesired connection that might eventually lead to short circuits on the board.
PCB Soldering Solder Bridging
When two or more pins bridge together, you’ll encounter trouble with your boards. Some of the significant causes of solder bridging include the following:
- We cannot fail to orient the same types of components in the same direction.
- We cannot fail to leave enough space between the pads and the solder mask layer.
- Designing and manufacturing printed circuit boards without paying attention to weight distribution. Such happens, especially when small components all sit on one side of the board.
Tombstone
If you have a marker or lifted components on your printed circuit board, it means that these components are higher than the PCB. Such mainly take place during the process of wave soldering, ending up resembling a tombstone.
- Lifted components is a common printed circuit board issue that a lot of PCB manufacturers face. Some of the most basic causes of lifted parts include the following:
- Using components that consist of varied lead or thermal solderability requirements.
- Wave is PCB soldering flexible PCBs that tend to bend as the components remain flat.
- An incorrect length of lead that happens to lift as it enters the solder bath.
PCB Soldering Excess Solder
Excess PCB solder on printed circuit boards is a big challenge that manufacturers face when producing these boards. If a board PCB passes through a wave soldering machine but takes too much solder, they’ll be an excess solder build-up. Excess solder on a printed circuit board will eventually have an impact on its functionality. Just like Lifted Components and Solder Bridging, there several major causes of excessive solder. Some of them include the following:
- We cannot use Failure to orient the same type components in the same direction during wave soldering.
- Employing the use of incorrect lengths to pad ratio when designing the printed circuit board.
- Conveyor belt running fast on the manufacturer’s side.
- For you to avoid cases of too much solder, it’s advisable not to get too enthusiastic to the extent of applying a lot of solder on the pins.
PCB Soldering Cold Joints
On a printed circuit board, cold joints appear somewhat pock-marked, lumpy, and dull. But what is a cold connection? In short, a cold junction takes place when the solder doesn’t melt completely, resulting in a lumpy or rough surface. Cold joints are highly unreliable, and a common printed circuit board soldering issue facing plenty of manufacturers. Cold joints occur due to some reasons worth noting. Primary reasons for cold joints are:
- The soldering iron or the solder joint itself is not heated enough until it is needed.
- Ground the pad directly without considering heat dissipation.
- Accumulation of flux under the circuit board causes the solder to adhere incorrectly to the connector.
- Use uneven SMD components in the design process.
- Use an inappropriate wave height between the circuit board and the solder wave.
Blow Holes and Pin Holes
Pinholes and blowholes are easy to identify on a printed circuit board. All you have to do is to look for any holes in the solder joints. In most cases, these holes extend from the layer that you are observing to the internal layers. Also, they may extend to the bottom of the board, bringing about connectivity issues. The main causes of blow and pins can include:
- Excess moisture that builds upon the circuit board.
- The components cannot be oriented in the same direction during welding.
- In the design stage, the via ratio is too small or too large.
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