Surface mount technology (SMT) is a key process in modern electronic manufacturing, and solder paste plays a vital role in SMT. The quality of solder paste in SMT patches is affected by many factors, and the following is a detailed description.

Main factors affecting the quality of solder paste in SMT patches:

1. Solder paste formula: The formula of solder paste is crucial to the quality of welding. The composition ratio, particle size, rheology and other characteristics in the formula directly affect the fluidity, adhesion, melting and other properties of solder paste.

2. Temperature control: The melting temperature of solder paste in SMT patches is one of the key factors. Too high or too low melting temperature will affect the wettability and connection quality of solder paste. Therefore, the temperature during heating and cooling must be strictly controlled.

3. Welding time: The welding time affects the flow and melting degree of solder paste. Too long or too short welding time may lead to poor welding, such as poor welding ball shape, insufficient solder joints and other problems.

4. Welding pressure: The pressure applied during welding directly affects the wettability and uniformity of the solder paste. Appropriate welding pressure can ensure that the solder paste is in full contact with the welding surface, thereby improving the welding quality.

5. PCB surface treatment: The treatment of the PCB surface has an important influence on the adhesion and connection quality of the solder paste. Different surface treatment methods (such as HASL, ENIG, OSP, etc.) will have different effects on the wettability of the solder paste.

6. Ambient humidity: Ambient humidity has a certain effect on the fluidity and viscosity of the solder paste. Too high or too low humidity may cause the fluidity of the solder paste to deteriorate, thereby affecting the welding quality.

7. Equipment accuracy and stability: The accuracy and stability of SMT equipment directly affect the control of the processes such as heating, movement and pressure application of the solder paste, and have an important impact on the welding quality.

8. Operator technical level: The operator's technical level and operating experience also have a direct impact on the welding quality. Skilled operators can adjust equipment parameters in time according to actual conditions to ensure the stability and controllability of the welding process.

The quality of solder paste in SMT patches is affected by many factors, and comprehensive consideration and optimization are required in terms of solder paste formula, heating control, surface treatment, environmental control, equipment performance and operating technology to ensure welding quality and stability.