First of all, we should know that in the SMT production line, the automatic solder paste printing machine requires very high precision, solder paste demoulding effect is good, the printing process is stable, suitable for the printing of densely spaced components. The disadvantage is that the maintenance cost is high and the knowledge level of operators is high.
1. When the scraper of the SMT printing machine moves forward at a certain speed and Angle, it will produce certain pressure on the solder paste, which will push the solder paste to roll in front of the scraper and produce the pressure needed to inject the solder paste into the mesh or leak hole;
2. The adhesive friction force of solder paste causes shear of solder paste at the junction of scraper and net plate of SMT stencil printer. The shear force reduces the viscosity of solder paste, which is conducive to the smooth injection of solder paste into the opening or leakage of template. There are certain restrictive relations among blade speed, blade pressure, blade Angle with template, and paste viscosity. Therefore, the printing quality of solder paste can be guaranteed only when these parameters are properly controlled.
3. When the blade moves forward with a certain speed and Angle, butt paste produce certain pressure, promote the solder paste before the scraper roller, will produce solder paste into mesh opening (template) the required pressure, solder paste viscosity friction to make solder paste in the scraper and sheet transfer shear opening (template), shear force make the solder paste viscosity decreased, thus successfully into the mesh; When the scraper leaves the opening of the template, the paste viscosity quickly returns to the original state.
When we work, only when the solder paste rolling in front of the scraper, can produce the pressure to inject the solder paste into the opening; The amount of solder paste is determined by the degree of solder paste filling the opening of the template, and the integrity of demoulding determines the solder paste leakage and the integrity of solder paste pattern.
Post time: Apr-14-2021