How do we guarantee the quality of SMT patches and solder paste printing?(1)

How do we guarantee the quality of SMT patches and solder paste printing?(1)

First of all, the quality problems caused by poor solder printing are as follows:

1. Insufficient solder paste (partial or even lack of overall defects) will result in insufficient solder joints after soldering, components

2, offset, components, components, upright.

3. Solder paste adhesion can cause short circuit and component misalignment after soldering.

4, the overall offset of solder paste printing: can lead to poor soldering of the entire board, such as tin, open circuit, local position, vertical parts.

5, solder paste is easy to cause short circuit after soldering

Second, the main factors leading to the shortage of solder paste:

1. When the printing press is working, add solder paste in time.

2. The quality of the solder paste is abnormal, and there are foreign objects such as hard blocks.

3. Solder paste that has not been used up before has expired and used twice.

4, board quality problems, there are inconspicuous covers on the pad, such as solder resist (green oil) printed on the pad.

5. The fixed clamping of the circuit board in the printing press is loose.

6. Missing solder paste, the template is not uniform.

7. There are contaminants in the solder paste template or on the circuit board (such as PCB packaging, template wiping paper, foreign objects floating in the air, etc.).

8. The solder paste scraper is damaged and the template is damaged.

9. The SMT parameters of the solder paste blade do not apply to SMT parameters such as pressure, angle, speed and demolding speed.

10. After printing the solder paste, it will be accidentally knocked out due to human factors.

Third, the main factors leading to the adhesion of solder paste:

1. Circuit board design defects, the pad pitch is too small.

2, the template problem, the pupil position is not correct.

3. The template is not wiped clean.

The problem with the template caused the solder paste to fall off severely.

5, solder paste performance is poor, viscosity is large, collapse is unqualified.

6. The fixed clamping of the circuit board in the printing press is loose.

7. The SMT parameters of the solder paste blade do not apply to SMT parameters such as pressure, angle, speed and demolding speed.

8. After printing the solder paste, it will be squeezed and stuck due to human factors.