Solder Paste Printing Common Issues and Solutions

1. Thin Solder Paste:

• Cause: Thin template, high squeegee pressure, or poor solder paste fluidity.
• Solution: Use a template with the right thickness, choose solder paste with correct particle size and viscosity, and reduce squeegee pressure.

2. Solder Paste Tip:

• Cause: Gap in the squeegee or incorrect solder paste viscosity.
• Solution: Adjust the squeegee gap or opt for solder paste with suitable viscosity.

3. Uneven Thickness on Pad:

• Cause: Stencil not parallel to the PCB, or unevenly mixed solder paste.
• Solution: Align the stencil and PCB properly, and ensure thorough mixing of solder paste before printing.

4. Solder Paste Falls to Both Ends of the Pad:

• Cause: High squeegee pressure, unstable board positioning, or incorrect solder paste properties.
• Solution: Adjust pressure, stabilize board positioning, or choose solder paste with appropriate properties.

5. Uneven Thickness and Burrs:

• Cause: Low solder paste viscosity and rough stencil opening hole walls.
• Solution: Opt for solder paste with slightly higher viscosity and inspect stencil opening quality before printing.

6. Incomplete Printing:

• Cause: Blocked opening, solder paste sticking, low viscosity, large metal powder particles, or worn scraper.
• Solution: Clear blockages, use appropriate viscosity solder paste, and replace worn scraper.