The basic principle of SMT patch processing is to use surface mount technology to mount electronic components onto printed circuit boards and fix the components through thermal reflow soldering. The following are several key steps of SMT patch processing to explain its basic principle:

PCB production and design: First, a well-designed PCB is required, which includes the placement positions of components and soldering points, and usually has a silk-screen layer to indicate the positions of components.

Steel mesh printing: Use a steel mesh to print on the pad areas on the PCB and apply a layer of solder paste. Solder paste is usually composed of metal powders (such as tin) and flux, and it is an important material used for soldering electronic components in surface mount technology (SMT) processing.

Component placement: The SMT placement machine accurately places electronic components on the corresponding solder paste on the PCB board. The precision of the surface mount technology (SMT) placement machine is extremely high and it can handle very small components.

Reflow soldering: After the components are placed, the PCB board passes through the reflow soldering furnace. When heated, the solder paste melts and cools to solidify, forming solder joints, which firmly solder the components onto the PCB board.

Inspection and Testing: After welding is completed, the quality of the welding is usually ensured through automatic optical inspection (AOI) and/or X-ray inspection. Then, electrical tests may also be conducted to ensure the functionality and performance of the circuit.

SMT patch processing allows for high-speed automated production and can achieve a relatively high assembly density. The design trend towards smaller, faster and higher-performance electronic products has made SMT the preferred technology in modern electronics manufacturing.