The accuracy of Solder Paste application steps directly affects SMT placement quality. First, select the appropriate squeegee type based on the PCB size and component layout, while ensuring the alignment accuracy between the stencil and PCB is within 0.05mm; otherwise, it will lead to uneven solder paste printing or missing prints.

During the printing process, the pressure and speed of the squeegee must be properly controlled. Excessive pressure will cause the solder paste to be squeezed to the edge of the pad, while too fast a speed will easily result in insufficient solder paste filling; both situations will affect the subsequent soldering effect of Reflow Soldering.

The amount of solder paste needs to be adjusted according to the size and thickness of the pad. Dispensing machines or manual printing are usually used, but in either case, the coverage area of the solder paste must not exceed 80% of the pad to avoid the risk of short circuits caused by excess.

Solder paste must be fully stirred before use to eliminate stratification that may occur during storage, and its viscosity must be checked to ensure it meets process requirements. If the viscosity is too high, printing will be difficult, while too low viscosity will easily cause collapse.

After printing is completed, first article inspection must be carried out immediately, focusing on checking the thickness, uniformity, and edge integrity of the solder paste. If abnormalities are found, stop the machine immediately for troubleshooting to avoid batch defects, and record relevant data for subsequent optimization.

The storage environment for solder paste must be kept at constant temperature and humidity, with temperature controlled at 25±3℃ and humidity not exceeding 60%RH; otherwise, its activity and shelf life will be affected. It is generally recommended to use it up within 48 hours, and performance must be re-tested if the time limit is exceeded.

In actual operation, attention should also be paid to the characteristic differences of solder pastes from different brands. For example, some silver-containing solder pastes are prone to oxidation at high temperatures, so preheating treatment is required before soldering, and exposure time should be reduced to lower the risk of oxidation.

The recycling and reuse of solder paste must also follow strict procedures. Solder pastes from different batches or brands must not be mixed arbitrarily to avoid soldering defects caused by component differences. RecycLED Solder Paste must be fully stirred and tested for performance before being reused.