Will the reflow soldering process produce pollution

SMT production process is to first print the solder paste on the corresponding pad of the circuit board, then paste the components on the pad brushed with the solder paste through the mounter, and weld the circuit board and components together through the reflow soldering process. So will SMT reflow soldering process produce pollution? Xiaobian is here to share with you.

In the whole SMT production process, two links are prone to pollution. The first link is in the process of printing and pasting. If you directly contact the solder paste or wipe the solder paste everywhere, it will cause pollution.

The second link is that in the reflow soldering process, the circuit board brushed with solder paste and pasted with components enters the reflow soldering furnace, and the welding production is formed by melting and cooling the solder paste through reflow soldering. There are chemicals that damage the body in the solder paste, so reflow soldering will produce pollution.

The main components in the solder paste are tin powder and flux. Tin powder affects the performance of the whole solder paste. The difference between tin powder and alloy composition lies in the metal composition. In the commonly used solder paste, the metal composition of tin powder includes 2 to 3 kinds of metals such as tin, lead, silver, copper and bismuth. Both flux and lead are harmful to human body. Therefore, if the reflow soldering is not operated properly, the reflow soldering will cause environmental pollution.

From the above analysis, there should be a recycling system of polluted air for reflow welding. The smoke exhaust and ventilation of reflow welding must be done well, and the reflow smoke filter should be installed, so as to reduce the waste gas pollution.

Routine maintenance contents of reflow welder:

1. Keep electrical wiring clean.

2. Regularly check whether the fan shaft sleeve is loose.

3. Regularly check whether the fan drive is flexible.

4. Regularly check whether the fan and transmission motor have abnormal noise.

5. Regularly check whether the air inlet and outlet holes are blocked by foreign matters.

6. Regularly check whether the transmission network belt is too loose.

7. Regularly check whether there is abnormal noise in the electrical appliances of the electric box.

8. Regularly check the transmission part for looseness and abnormal noise.

9. Before starting the machine, check whether the working voltage of the machine is within the safe range or stable to ensure that all parts of the machine can work normally and safely.

10. At the same time, check whether the various setting parameters during startup and the last shutdown are consistent.

11. When shutting down, do not stop the conveyor belt in the machine still at high temperature, so as to avoid the accelerated aging of the conveyor belt under high temperature. It is best to stop the conveyor belt after the temperature in the body drops.

12. When the general machine works every day, due to the requirements of indoor environment, the machine shell and residual crops at the air outlet shall be cleaned before going up and down every day To keep the appearance of the machine clean and smooth.

13. Conveyor belt: lubricate the drive roller chain and apply it with soaked high-temperature lubricating oil (molybdenum disulfide) every two months; When the follow-up roller (outside the device) can maintain the tension of the conveyor belt, the tensioning slide should be kept clean and free of dust Or when the parallelism of the two rollers needs to be adjusted, adjust the top wire exposed near the follow-up roller.

14. Motor: the machine motor operates at high speed under high temperature for a long time. High temperature lubricating oil must be added to its shaft wheel at least twice a week to keep it running smoothly.

15. Fan: when the fan in the machine is running, the air in the agitator flows. At the same time, various residual crops in the machine are adhered to the fan blade and motor. It is required to clean in time to avoid short circuit or burning the fan.

16. Ground wire: when the machine uses three-phase five wire system, there must be a ground wire to connect the machine with the earth Check whether the ground wire is connected before starting the machine.