1. Proper Control of Soldering Temperature:

When flux spreads evenly from the soldering tip to the solder pad, sufficient heating has been completed. At this moment, lift the soldering iron quickly to form smooth, rounded solder joints. If only a tiny amount of solder remains after lifting the tip, it means insufficient heating time, low temperature or contaminated flux. If the solder pad shifts before the iron is lifted, the heating duration and temperature are excessive. The optimal tip temperature is reached when the workpiece melts rapidly without generating smoke.

2. Apply Appropriate Amount of Solder:

Adjust the solder feeding volume according to the size of solder joints. The solder should fully cover the pad and form smooth, well-proportioned joints. Excessive solder does not equal better soldering; oversize joints tend to create cold solder layers where solder only accumulates on the surface without proper fusion. If solder is insufficient on the first pass, reapply solder only after the previous layer fully melts before pulling away the iron. If too much solder is applied initially, remove the excess with the soldering tip.

3. Reasonable Soldering Time Control:

Controlling soldering duration is a key part of the soldering process. For PCB soldering, 1 to 2 seconds is the optimal timeframe; prolonged heating should be avoided.

4. Keep Solder Joints and Workpiece Surfaces Clean:

Before soldering with an automatic soldering machine, thoroughly remove dirt, oxides and rust from pads and workpiece surfaces. Residues on the surface will severely compromise soldering quality if uncleaned beforehand.