Possible causes of component displacement after SMT

1. Improper solder paste application: Solder paste is a critical factor used to adhere SMT components to PCBs. If the solder paste is not distributed evenly or accurately, it may cause components to shift during the soldering process. This may be caused by incorrect solder paste printing, offset, or uneven thickness.

2. Improper component positioning: The positioning of components on the placement machine is critical. If the component is not properly positioned on the PCB, it will cause the component to shift. This may be caused by a malfunction of the placement equipment, inaccurate calibration, or problems with the component itself.

3. Component quality issues: Sometimes, there may be problems with the component itself, such as uneven pins, irregular or skewed packages, etc. These problems may cause components to shift during the soldering process.

4. Thermal stress: During the SMT soldering process, temperature changes may cause thermal stress between the PCB and the component, which may cause component shifting. This is a particularly important issue because during the high temperature process, the solder becomes liquid and causes the component to adhere to the PCB.

5. Vibration and mechanical shock: Vibration or mechanical shock on the production line may cause component shifting. These vibrations and shocks may come from conveyor belts, placement machine operations, or other mechanical equipment.

6. Improper reflow process: The reflow process is the last step in SMT component soldering. If it is not performed correctly, it may cause component displacement. Improper temperature gradients, overheating, or overcooling may affect soldering.

7. Electrostatic attraction: Electrostatic attraction may cause components to be adsorbed and displaced during handling and placement. This is especially important when handling electrostatic sensitive components.

8. Human error: Operator errors such as incorrect component loading, incorrect process control, or inappropriate operation may also cause component displacement.

To reduce the risk of component displacement in SMT placement processing, it is necessary to properly implement process control, calibrate equipment, ensure component quality, and pay attention to the maintenance of production line equipment. In addition, regular inspection and quality control steps can help catch and correct component displacement problems.