1. The single process parameters of scraper pressure, scraper speed and demoulding speed have a great impact on the solder paste printing quality. The solder paste printing quality on different types of pads has the same response to the changes of process parameters. In this case, the printing quality of slender and small-size pads with fine egg spacing is more likely to fail to meet the acceptance standards.

2. Under the premise of ensuring that the pressure of the scraper is higher than the internal pressure of the solder paste, it has no obvious impact on the printing quality of the solder paste, but too high pressure will affect the alignment accuracy of the patch steel mesh and PCB, accelerate the wear of the laser steel mesh and the scraper, at the same time, the printed solder paste body first increases and then decreases with the increase of the scraper pressure, and the height of the solder paste decreases with the increase of the scraper pressure.

3. The speed of the scraper has a great impact 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 solder paste printed first decreases and then increases with the increase of scraper speed. There is no obvious relationship between the height of solder paste and scraper speed.

4. The printing quality decreases with the increase of demoulding speed, which is mainly manifested in the sharpening on the slender pads such as QFP, blocking the opening of SMT steel mesh and causing missing printing. At the same time, the volume of printed solder paste first increases and then decreases with the increase of demoulding speed, and the height of solder paste first increases and then decreases with the increase of demoulding speed.

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

6. The process window of solder paste printing is determined through experiments. The previous research on the influence of process parameters on the printing performance of solder paste is verified through a complete surface mount test, and the accuracy of the process window is verified. This process window can provide a reference for actual production.