The speed of the scraper of the solder paste printing machine is closely related to the viscosity of the solder paste. The slower the speed of the scraper, the greater the viscosity of the solder paste. Similarly, the faster the speed of the scraper, the smaller the viscosity of the solder paste. The scraper of solder paste printer is too wide compared with PCB, which requires more pressure and more solder paste to participate in its work, which will cause the waste of solder paste. The width of the scraper is generally the length of PCB (printing direction) plus about 50mm to ensure that the scraper head falls on the metal template. Printer receives PCB loader → camera identification and position → PCB repaired by vacuum or splint equipment → lifting equipment Elevator PCB contacts steel mesh → scraper drops to SMT printing position according to setting → → scraper starts printing, scraper returns to original position and printing ends → PCB and steel mesh begin to separate → 2D inspection of printing effect → PCB issue → steel mesh cleaning → next printing action is completed 。
The key factor controlling the amount of solder paste, the opening of mesh, or the setting of machine, depends on the situation. If the machine is set significantly away from the process window (each paste is the same), the aperture size will not be very helpful. The same is true for steel mesh. If the standard design rules from wall area to opening area are broken, few machine settings will help.