1. The single process parameters of squeegee pressure, squeegee speed, and demolding speed have a great influence on the quality of solder paste printing. The quality of solder paste printing on different types of pads has the same response to changes in process parameters. The print quality of the small size pads is more likely to fail the acceptance criteria in this case.

2. The squeegee pressure has no obvious effect on the printing quality of the solder paste under the premise of ensuring that it is higher than the internal pressure of the solder paste, but too high pressure will affect the SMD stencil, PCB alignment accuracy, accelerate the wear of the laser stencil and the squeegee, and at the same time , the printed solder paste increases first and then decreases with the increase of the squeegee pressure, and the solder paste height decreases with the increase of the squeegee pressure.

3. The speed of the scraper has a great influence on the printing quality. The printing quality decreases with the increase of the speed. The main table is lack of printing, contamination, etc. At the same time, the volume of the printed solder paste first decreased and then increased with the increase of the squeegee speed, and the solder paste height had no obvious relationship with the squeegee speed.

4. The printing quality decreases with the increase of the demolding speed, which is mainly manifested in the sharpening on the slender pads such as QFP, blocking the opening of the SMT stencil and causing the lack of printing. At the same time, the volume of the printed solder paste increases with the stripping. As the mold speed increases, it first increases and then decreases, and the solder paste height first increases and then decreases with the increase of the demolding speed.

5. Combining the solder paste printing process and the clay properties of the solder paste, it is determined through analysis that the above-mentioned effects of various process parameters on the printing quality are caused by the combination of the edge performance of the solder paste and the pressure of the solder paste content.

6. The process window of solder paste printing was determined through experiments, and the previous research on the effect of process parameters on the performance of solder paste printing was verified through a complete surface mount test, and the accuracy of the process window was verified, which can be used for actual production. for reference.