Solder paste printing is an important process in SMT assembly industry. According to the statistics of experts, nearly 70% of the defects in SMT assembly are caused by printing. In order to reduce the defects and improve the pass through rate, we have to pay attention to the quality of SMT steel mesh, the most important consumable affecting the printing effect. The following are some precautions for improving the quality of SMT steel mesh summarized by Linchuan precision for your reference:

　　1. Before the fabrication process, we have discussed the fabrication process of steel mesh. We can know that the best process should be electropolishing after laser cutting. Both chemical etching and electroforming are easy to produce errors, such as making sullain, exposure and development, and electroforming is also affected by substrate unevenness.

　　2. The materials used include mesh frame, wire mesh, steel sheet, adhesive, etc. The mesh frame must be able to bear the relay of a certain program and have a good levelness; the polyester mesh is the best choice for the mesh, which can keep the tension stable for a long time; the 304 steel is the best choice, and the matte will be more conducive to the rolling of solder paste (adhesive); the adhesive must be strong enough and resistant to certain corrosion.

　　3. The quality of opening design has the greatest influence on the quality of steel mesh. As discussed before, the design of opening should consider the manufacturing process, width thickness ratio, area ratio, experience value, etc.

　　4. The integrity of production data will also affect the quality of steel mesh. The more complete the data, the better. At the same time, when the data coexist, it should be clear which one shall prevail. In addition, generally speaking, making SMT steel mesh with data file can reduce the error as much as possible.

　　5. Using the correct printing method can keep the quality of the steel mesh, on the contrary, incorrect printing methods such as excessive pressure, uneven steel mesh or PCB during printing, etc. will damage the steel mesh.

　　6. Cleaning solder paste (adhesive) is easy to solidify, if not cleaned in time, it will block the opening of steel mesh, and the next printing will be difficult. Therefore, after the steel mesh is removed from the machine or the solder paste is not printed on the printing machine for 1 hour, it should be cleaned in time.

　　7. The steel mesh shall be stored in a specific storage place and shall not be placed randomly, so as to avoid accidental injury to the steel mesh. At the same time, the steel mesh should not be stacked together, so that it is not easy to take and the mesh frame may be bent.

　　Do the above work well and your SMT steel mesh quality will be improved, so that the SMT assembly pass through rate will be improved.