How to locally increase the amount of solder paste or solder in the SMT process.

By adjusting the opening size of the steel mesh, you can directly control the amount of solder paste deposition. Enlarge the opening: Enlarge the opening size of the steel mesh corresponding to the pad that requires more solder, thereby increasing the amount of solder paste deposition. Use special shape openings: trapezoidal or racetrack openings allow more solder paste to be deposited on the edge of the pad.

• Advantages: simple, low cost, no need to change the existing process.

• Disadvantages: If the operation is improper, it may affect the printing quality; Limited to the minimum feature size of the steel mesh.

The same PCB is printed multiple times to increase the amount of solder paste deposition.

• Advantages: The amount of extra solder can be precisely controlled; Suitable for specific areas where more solder is needed.

• Disadvantages: increase production time and cost; If the alignment is not accurate, it may cause printing problems.

before reflow welding, place the solder preform on the PCB pad.

• Advantages: The amount of solder can be precisely controlled; Suitable for applications requiring large amounts of solder.

• Disadvantages: Manual placement is costly and time-consuming; Automated placement may require additional process steps.

for through-hole components or specific pads, solder dip or wave welding can be used to increase the amount of solder.

• Advantages: Quickly and effectively add a large amount of solder; Suitable for adjustment after reflow welding.

• Disadvantages: Not applicable to all SMT applications; If not properly controlled, it may result in solder bridging.

Using higher metal content or different rheological properties of the solder paste, you can achieve a higher amount of solder after reflux.

• Advantages: Can be applied to the whole board or selective area; There is no need to change the steel mesh design.

• Disadvantages: May affect reflux curve and overall process; Requires the use of special solder paste, increase the cost.