Here comes main reasons for the failure:

1. Components foot/ legs defective: coating, pollution, oxidation, common surface;

2. Solder pad rejected: coating, pollution, oxidation and warping;

3. Poor quality of soldering parts: composition, excessive and oxidation;

Here soldering parts normally including: soldering wire, soldering rod, brazing and soldering alloy.

4. Soldering flux quality problem: low welding resistance, high corrosion and low SIR;

5. Poor control defect of processing parameters: design, control and equipment;

6. Other auxiliary material defects: adhesive, cleaning agent.

PCBA soldering failure has a great influence on circuit performance, therefore, how to improve the design process, structure parameters, welding process, solder joint reliability, improve the yield of PCBA processing during PCBA fabricating, be a constantly job for all PCB related workers.