Reasons for SMT cold soldering, SMT false soldering, SMT empty soldering, and SMT virtual soldering in SMT welding

In today's SMT process, most manufacturers face different SMT process defects, such as solder balls, residues, false soldering, cold soldering, empty soldering, and virtual soldering; Especially the last four types, many friends cannot distinguish the difference between them because these four types of bad things seem to be the same. Below are the definitions of these four types of bad things:

1. Fake welding refers to the situation where it appears to be welded on the surface, but in reality it is not welded on. Sometimes, by pulling it with your hand, the lead can be pulled out from the solder joint.

2. Virtual soldering refers to the phenomenon where only a small amount of solder is attached to the solder joint, resulting in poor contact and intermittent continuity. Both virtual soldering and false soldering refer to the insufficient tin coating on the surface of the solder joint, and the lack of tin fixation between the solder joints, which is caused by the incomplete cleaning of the solder joint surface or the use of too little solder flux.

3. Empty welding refers to the welding point that should have been welded but not yet welded. Insufficient solder paste, problems with the parts themselves, placement of the parts, and prolonged storage time after soldering can cause empty soldering.

4. Cold welding refers to the absence of a solder strip at the solder interface of a component, resulting in poor soldering quality. Low soldering temperature, short soldering time, and tin eating issues can cause cold soldering.

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