Welding is a crucial step in PCBA processing, and its quality standards mainly include the following aspects:
1. Welding fullness: The solder joints should have appropriate size and shape to ensure sufficient contact with the component pins and pads, and the solder penetration requirement is usually above 75%.
2. Solder Paste Quantity Control: The amount of solder paste on the solder joint should be just right, neither less than 1/4 of the size of the component soldering end, nor too much to cause short circuits or affect electrical performance.
3. Component misalignment: The component position must be accurately aligned and not deviate from the center of the solder pad by more than 1/4 of the size of the component solder end.
4. Floating phenomenon: The distance between the bottom soldering surface of the component and the PCB pad should not exceed 0.5mm to avoid the “tombstoning effect”.
5. Tin bead management: The diameter of the tin bead should be less than the specified value, generally not exceeding 0.1mm, to prevent the risk of short circuit.
