Solder paste printing is a highly complex technology used in SMT chip processing. It is influenced not only by materials, but also by equipment and parameters. By carefully controlling every subtle aspect of the printing process, it becomes evident that success or failure is determined by the details. In order to avoid the common shortcomings that often occur during solder paste printing, the following are the most common issues and their corresponding solutions:

Thin solder paste:

Cause: The template is too thin, the squeegee pressure is too high, or the solder paste has poor fluidity.
Solution: Use a template with the appropriate thickness, select solder paste with the right particle size and viscosity, and reduce the squeegee pressure.

Solder paste tip:

Cause: The gap in the squeegee or the viscosity of the solder paste.
Solution: Adjust the squeegee gap or choose solder paste with suitable viscosity.

Uneven thickness on pad:

Cause: The stencil is not parallel to the printed circuit board, or the solder paste is not uniformly mixed.
Solution: Adjust the orientation of the stencil and the printed board, and fully mix the solder paste before printing.

Solder paste falls to both ends of the pad:

Cause: High squeegee pressure, unstable printed board positioning, or inappropriate solder paste viscosity or metal content.
Solution: Adjust the pressure, re-fix the printed board, or select solder paste with the appropriate viscosity.

Uneven thickness and burrs:

Cause: Low viscosity of the solder paste and roughness of the stencil opening hole wall.
Solution: Choose solder paste with slightly higher viscosity and check the quality of the stencil opening before printing.

Incomplete printing:

Cause: Blocked opening or solder paste sticking to the bottom of the template, low viscosity of the solder paste, presence of large metal powder particles, or worn scraper.
Solution: Address the blocked opening, use solder paste with appropriate viscosity, and replace the worn scraper.