A. The main factors leading to the overall offset of solder paste printing

1. The positioning reference point on the circuit board is not clear

2. The positioning reference point on the circuit board is not aligned with the reference point of the laser stencil

3. The fixed clamping of the circuit board in the printing machine is loose, and the positioning thimble is not in place

4. The optical positioning system of the printing press is faulty

5. Solder paste leakage and patch stencil openings do not conform to the design documents of the circuit board.

B. The main factors that lead to the sharpening of the printed solder paste

1. There are problems with performance parameters such as solder paste viscosity

2. There is a problem with the setting of the demoulding parameters when the circuit board is separated from the missing SMT stencil.

3. There are burrs on the hole wall of the stencil hole