What are the reasons for rosin joint in processing?（1）

There are so many reasons for the rosin joint of the finished product in PCB processing.

1 rosin joint caused by process factor

1）Missing solder paste

2）Insufficient amount of solder paste applied

3）Steel mesh aging, poor leakage

2. rosin joint caused by PCB

1）PCB have poor solderability

2）There are via holes on the pads

3. rosin joint caused by component factors

1）distortion of component pins

2）Oxidation of component pins