SMT solder paste printing standard and common defects

2022-05-07 40

SMT solder paste printing standards and common defects are: less tin, even tin, sharp point, shift, missing printing, more tin, collapse, dirty PCB, etc. The printing thickness of Huawei Guochuang solder paste is-0.02 mm ~+0.04 mm of the thickness of steel mesh;


SMT solder paste printing standard


1. printing standard of CHIP components

1. No deviation of solder paste;

2. The amount and thickness of solder paste meet the requirements;

3. The solder paste is well formed without collapse and fracture;

4. Solder paste covers more than 90% of the pads.


2. CHIP component printing is allowed

1. The hole of the steel mesh has shrinkage, but the solder paste still covers 85% of the pad;

2. Uniform amount of solder paste;

3. The thickness of solder paste is within the required specification.

4. Printing offset is less than 15%


3. CHIP components are rejected for printing

1. Insufficient amount of solder paste.

2. The amount of solder paste at two points is uneven.

3. Solder paste printing offset more than 15% pads


4. SOT component solder paste printing standard

1. No deviation of solder paste;

2. Solder paste completely covers the pad;

3. Uniform solder paste at three o'clock;

4. The thickness of solder paste meets the test requirements.


5. Solder paste printing of SOT components is allowed

1. The amount of solder paste is uniform and well formed;

2. More than 85% solder paste covers the pad;

3. Printing offset is less than 15%;

4. The thickness of solder paste meets the specification requirements.


6. Solder paste printing of SOT components is rejected

1. More than 85% of the solder paste does not cover the pad;

2. There is a serious lack of tin


7. Printing standard of diode and capacitor solder paste

1. The solder paste is well printed and formed;

2. Solder paste printing has no offset;

3. The solder paste thickness test meets the requirements;


8. Printing of diode and capacitor solder paste is allowed.

1. The amount of solder paste is sufficient;

2。 The solder paste covers more than 85% of the pads;

3. The solder paste is well formed;

4. Printing offset is less than 15%.


9. Solder paste printing of diode and capacitor is rejected.

1. More than 15% of solder paste on the pad is not completely covered;

2. Solder paste offset exceeds 15% of pads.


10 Pad spacing =1.25-

0.7MM solder paste printing standard 1. Each solder paste covers each pad;

2. The amount of solder paste is uniform and the thickness is within the test range;

3. The solder paste is well formed, without tin and collapse;

4. No deviation phenomenon.


1 pad spacing =1.25-0.7MM solder paste printing is allowed.

1. The solder paste is well formed, and the solder foot of the component is full of solder, without collapse or bridging;

2. There are offset pads, but not more than 15%;

3. The solder paste thickness test meets the requirements;

4. There is no defect after furnace welding.


12. Solder paste printing with pad spacing =1.25-0.7MM is rejected.

1. More than 15% of solder paste does not cover the pad;

2. The deviation exceeds 15%;

3. Solder paste almost covers two pads, which is easy to cause short circuit behind the furnace;

4. Solder paste printing to form bridge connection.


13. Pad pitch =0.65MM solder paste printing standard

1. the solder paste printing of each pad covers the pad;

2. The solder paste is well formed, without collapse, deviation or bridging;

3. The thickness of solder paste meets the requirements.


14, pad spacing =0.65MM solder paste printing acceptance

1. The solder paste is well formed, without bridging and collapse;

2. The solder paste thickness test is within the specification;

3. The solder paste offset of each point is less than 10% of the pad.

4. There is no defect after furnace welding.


15. Solder paste printing with pad spacing =0.65MM is rejected.

1. More than 10% of solder paste does not cover the pad;

2. The deviation exceeds 10%;

3. Solder paste almost covers two pads, which is easy to cause short circuit behind the furnace;


16. Solder paste printing standard with pad spacing ≤ 0.5mm.

1. the solder paste printing of each pad covers the pad;

2. The solder paste is well formed without collapse;

3. The thickness of solder paste meets the requirements.


17. solder paste printing with pad spacing ≤0.5MM is accepted.

1. Although the solder paste formation is slightly poor, the solder paste thickness test is within the specification;

2. There is no deviation, bridging and collapse of solder paste at each point;

3. There is no false soldering with less tin behind the furnace.


18. Solder paste printing with pad spacing ≤0.5MM is rejected.

1. The solder paste is poorly formed and broken;

2. solder paste collapses and bridges;

3. The solder paste coverage is obviously insufficient.


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