1. 0.5mm pitch QFP pad length is too long, resulting in short circuit.
2. PLCC socket pads are too short, resulting in false soldering.
3. IC’s pad length is too long and the amount of solder paste is large resulting in short circuit at reflow.
4. Wing-shaped chip pads are too long to affect the heel solder filling and poor heel wetting.
5. The pad length of chip components is too short, resulting in shifting, open circuit, can not be soldered and other soldering problems.
6. The length of the pad of chip-type components is too long, resulting in standing monument, open circuit, solder joints less tin and other soldering problems.
7. Pad width is too wide resulting in component displacement, empty solder and insufficient tin on the pad and other defects.
8. Pad width is too wide, component package size and pad mismatch.
9. The pad width is narrow, affecting the size of the molten solder along the component solder end and the metal surface wetting spread at the PCB pad combination, affecting the shape of the solder joint, reducing the reliability of the solder joint.
10. Pad directly connected to a large area of copper foil, resulting in standing monument, false solder and other defects.
11. Pad pitch is too large or too small, the component solder end can not overlap with the pad overlap, will produce a monument, displacement, false solder and other defects.
12. The pad pitch is too large resulting in the inability to form a solder joint.
Post time: Dec-16-2021