Common Causes of Poor Soldering in PCB Design

• Particulate impurities in the plating layer or grinding debris left on the circuit board surface.
• Contamination with grease, impurities, or residual silicone oil.
• Areas on the board surface lacking tin with particulate impurities in the plating layer.
• Rough high-potential coating, signs of burning, and areas without tin.
• Severely oxidized tin surface, dull copper surface in certain areas.
• Inconsistent plating between board sides, distinct bright edges around holes.
• Clear bright edges on low-potential holes, rough high-potential coating.
• Insufficient soldering temperature or time, improper flux usage.
• Inadequate tin plating coverage, dark red areas on the board surface.

Causes of Poor Tinning on Circuit Boards

• Unbalanced bath composition, low current density, insufficient plating time.
• Inadequate number and uneven distribution of anodes.
• Low or excessive concentration of tinting agent.
• Large anode size, high current density, improper wire density in certain areas.
• Residual film or organic matter before plating.
• High current density, inadequately filtered plating solution.

Strategies to Improve PCB Electro-Tinning Defects

1. Regular chemical analyses and timely syrup composition adjustments.
2. Periodic monitoring of anode consumption and adding anodes as needed.
3. Hearst cell analysis for light agent adjustment.
4. Rational anode distribution, proper current density reduction, and wiring design.
5. Enhanced pre-plating treatments.
6. Reduced current density, regular maintenance of the filter system.
7. Strict control of storage time and environmental conditions.
8. Use of solvents for debris cleaning and specialized solvents for silicone oil.
9. Precise temperature control during soldering (55-80°C) with sufficient preheating.
10. Proper application of soldering flux.

Understanding and addressing these issues are crucial in the PCB industry to ensure high-quality soldering and tinning processes.