9. Asymmetry
a.) Appearance Characteristics: The solder does not flow to the pad.
b.) Hazards: Insufficient strength.
c.) Possible Causes:
— The solder has poor fluidity.
— Insufficient flux or poor quality.
— Insufficient heating.
10. Loose
a.) Appearance Characteristics: The wire or component lead can be moved.
b.) Hazards: Poor or non-conduction.
c.) Possible Causes:
— Leads move before the solder is solidified and cause voids.
— The lead is not processed well (poor or not wetted).
11. Sharpen the Tip
a.) Appearance Characteristics: The tip is showing.
b.) Hazards: Poor appearance can easily cause bridging.
c.) Possible Causes:
— Too little flux and too long heating time.
— Improper evacuation angle of the soldering iron.
12. Bridge
a.) Appearance Characteristics: Adjacent wires are connected.
b.) Hazards: Electrical short circuit.
c.) Possible Causes:
— Too much solder.
— Improper evacuation angle of the soldering iron.
13. Pinhole
a.) Appearance Characteristics: Visual inspection or low-power amplifier can see holes.
b.) Hazards: The strength is insufficient, and the solder joints are easily corroded.
c.) Possible Causes:
— The gap between the lead and the pad hole is too large.
14. Bubbles
a.) Appearance Characteristics: There is a spit-fire solder bulge at the root of the lead, and a cavity is hidden inside.
b.) Hazards: Temporary conduction, but it is easy to cause poor conduction for a long time.
c.) Possible Causes:
— The gap between the lead and the pad hole is large.
— Poor lead infiltration.
— The welding time of the double-sided board plugging the through hole is long, and the air in the hole expands.
15. Copper Foil is Upturned
a.) Appearance Characteristics: The copper foil is peeled from the printed board.
b.) Hazards: The printed board is damaged.
c.) Possible Causes:
— The welding time is too long and the temperature is too high.
16. Stripping
a.) Appearance Characteristics: The solder joints peeled off from the copper foil (not the copper foil and the printed board peeled off).
b.) Hazards: Open circuit.
c.) Possible Causes:
— Bad metal plating on the pad.
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