Solder paste printing machine is a necessary production equipment in SMT processing and production industry. Its working principle is: first fix the circuit board to be printed on the rigid positioning table, then the left and right scrapers of the printing machine leak the solder paste or red glue on the corresponding pad through the steel mesh, and input the PC3 with uniform missing printing to the mounter through the transfer table for automatic mounting. Because it has the advantages of small volume, light weight and breaking through the traditional industrial technology. SMT processing and production enterprises on a large scale must use solder paste printing machines. In this way, the failure of solder paste printing machine has become a focus topic of public concern.

1、 There are burrs on the solder paste on the solder pad of the circuit board after printing by the large-size solder paste printer

There are three possible reasons for this phenomenon:

1、 The inner wall of the steel mesh in the equipment is not smooth enough, which leads to the phenomenon of hand burr.

2、 The viscosity of the humming paste selected by the operator does not meet the standard and is smaller.

3、 The thickness of the steel mesh in the equipment is too large, which leads to the emergence of burrs.

Solution: operators can first select the solder paste suitable for the equipment, and then use professional tools to adjust the distance between PCB and steel mesh in the equipment. They can replace or change the opening mode and thickness of steel mesh

2、 The thickness of solder paste on the solder pad of circuit board is inconsistent after printing by large-size solder paste printer

If such a phenomenon occurs, there are three possible reasons:

1、 The PCB in the equipment is not parallel to its steel mesh.

2、 The operator did not hold the solder paste evenly, resulting in inconsistent thickness.

3、 Because the uniformity of the selected alloy particles is not up to standard.

Solution: the operator can first adjust the parallelism between the PCB and the steel mesh in the equipment with a standard tool, and then stir the solder paste evenly before using the equipment.

3、 After printing by large-size solder paste printer, the solder paste on the circuit board pad is slightly thinner after forming

If this happens, there are three possible reasons:

1、 It may be because the thickness of the steel mesh of the equipment does not meet the standard and is too small.

2、 It may also be due to excessive pressure on the scraper in the equipment.

3、 The selected solder paste has the problem of poor fluidity.

Solution: the operator can first replace the steel mesh and select the steel mesh with moderate thickness. Then inform the professional maintenance personnel to adjust the pressure of the equipment scraper to make it meet the standard. Choose good solder paste with moderate viscosity

It can be said that the solder paste printer operators of almost every SMT processing and production enterprise have encountered the above three kinds of solder paste printer printing faults. For the solder paste printer operators with good technology, they can know the solutions according to their own experience. If 0 is better than the new solder paste printer operators, it will be a headache.