Welding bridge:

A solder bridge is an accidental electrical connection between conductors that is not required due to a small piece of solder. They are also known as “short circuits” in PCB terminology. It is difficult to detect welded Bridges when thin spacing components are involved. If it is not resolved, it can cause damage to other components and circuit boards. A welding mask (i.e., a thin layer of polymer is applied to the copper traces on the printed circuit board to protect it from oxidation and avoid solder bridge formation between pads. This welding mask is necessary for the mass production of PCBS, but it is less useful in the case of hand-welded PCB components. For circuit boards to be soldered automatically, solder bath and reflow soldering techniques are trending high. To avoid welding Bridges during PCB assembly, it is first necessary to determine the appropriate type of welding mask to be used during PCB assembly. This can be a sensitive consideration when getting the proper PCB layout and PCB type for your project.

Electronics manufacturers should thoroughly investigate the advantages and disadvantages of each type of solder film before deciding whether to choose epoxy liquid, liquid photoimage solder film (LPSM) or dry film photoimage solder film (DFSM). They can even help PCB manufacturers consult and seek the perfect PCB assembly through a clear technical and PCB production process. For all electronics manufacturers, preventing welded Bridges may involve additional investment of time and money, but it can help you achieve significant long-term returns.

Reasons for welding bridge:

The root cause of weld bridge is improper PCB layout. The package size of its components and the idea of insufficient use of combined materials have increased due to the need to introduce more compact and faster technologies. This is a big challenge for oems, requiring perfect and proper PCB layout. They often end up compromising on PCB layouts in order to bring new products to market.

Other causes of bridging include a lack of welding resistance between pads on the circuit board.Insufficient polymer layers on the COPPER trace lines of the PCB, often called the weld mask, also cause problems with the weld bridge. When device spacing is 0.5mm or less, improper pad clearance ratio can also be the cause of the bridge. Incorrect template specifications can lead to excess solder paste, which can lead to Bridges. Due to improper sealing between PCB and solder plate, improper thickness of template, errors in placement of surface mount components or in comparison with PCB, poor solder paste registration, uneven distribution of solder paste, these are common problems that lead to solder bridge during PCB assembly.

Preventive measures:

Verify that each wire is coated with flux resistance between them and is not usable due to tight tolerances, and then it explains the design changes around that particular component. The recommended 0.127 mm thick welding template, stainless steel template with laser cutting is also suitable for 0.5 mm device spacing. These are precautions to avoid welded Bridges and get the perfect PCB assembly solution.