The best way to address Metal core PCB solder bridge defects is to prevent them from occurring in the first place. Many of the root causes for solder bridging comes from issues either related to design or process. If one solder bridge occurs, there is a higher likelihood that it will occur in other printed circuit boards that are manufactured.

Solder Masking – Solder masking is a vital step in preventing solder bridges from forming, and should be applied early in the manufacturing process. While solder mask color may be altered for aesthetic purposes, green solder masking has the highest contrast and the lowest cost, making it effective for spotting issues before they become a problem.

Design – Miniaturization is a crucial element of effective printed circuit board design. Unfortunately, designs that include pads and stencils that are too close to each other can result in solder bridging. Following the best industry practices for Metal core PCB board design and layout can help you avoid this costly mistake.

Solder Application – Solder bridging can frequently occur when too much solder is applied to pads. You may have to adjust the solder paste printing pressure, or the pressure for pick and place nozzles – excessive force can squeeze the paste out of the pads, forming solder bridging defects. Finally, ensure that you are not mixing old and new flux, and that the flux you are using has not expired.

Stencil – When a stencil is not properly cleaned, residue can accumulate and result in solder bridging defects in subsequent printings. Make sure to clean the stencil quickly and efficiently to reduce the chance of solder bridging.

As mentioned before, there are many possible causes for solder bridge defects, so some trial and error may be required to rout out the issue. If the design of your printed circuit board meets the best available criteria, examine your process to see that the stencil is clean and excess pressure is not being applied during solder application.