It is very important to use constant temperature and humidity air conditioner in SMT printing. After installing monomer constant temperature and humidity precision air conditioner on large-size solder paste printing machine, the viscosity of solder paste rises slowly, the plug hole is greatly reduced, there is no accumulation, drawing, edge defects, and the printing quality is improved in an all-round way. The monomer constant humidity function ensures that it is strictly controlled within the set parameters, 24 hours a day and 365 days a year, providing a better operating environment for SMT printers. It provides more effective and reliable conditions to ensure the printing quality of SMT.

So, why use solder paste printing machine, constant temperature and humidity machine in the process of solder paste printing?

1. Effect of temperature on solder paste. Experiments show that the viscosity of solder paste decreases with the increase of temperature.

2. Lower viscosity will lead to the following defects.

a. When the viscosity decreases, the backlog diffuses, and when the solder paste printer prints, the solder paste diffuses and bridges laterally.

b. When the viscosity becomes low, it will collapse. The solder paste block printed by the solder paste printer has insufficient retention and collapse bridging. This phenomenon usually occurs after the printing process.

c. Low viscosity will lead to defect of solder paste printer, poor demoulding, plug hole and poor forming. Therefore, because the temperature has a great impact on the viscosity of wet paste and directly affects the core quality of products, it is very important to control the working temperature inside the printer in printing.

3. Experiments show that when the humidity is too low and the weather is dry, the solder paste of the solder paste printing machine is easy to dry out, which is particularly obvious in winter in the north. When the relative humidity is lower than 40%, the viscosity of solder paste decreases with the decrease of humidity. More than 60%, because the air contains too much water vapor, the water droplets crystallize on the surface of the solder paste, which has a great impact on the quality of the solder paste.

Common causes and treatment methods of printing paste offset fault of solder paste printing machine:

① Coordinate offset. Treatment method: adjust the coordinates of the solder paste printer

② Poor identification of calibration points. Processing method: debug the vision system of the printer or rewrite the coordinates of the calibration point.

③ Loose fixation of wire mesh, treatment method: check the fixation of wire mesh.

④ PCB stop board is unstable. Treatment method: check whether the substrate positioning fixture, tray fixture and vacuum of solder paste printer can stabilize PCB.

⑤ The camera hit the PCB. Solution: lock the camera cover on the system.

⑥ Confirm that the fixed shaft of the solder paste printer is loose and the motor driver card is abnormal. Treatment method: which direction deviates, support to check the shaft fixing screw, coupling and motor driver card.