Surface Mount Technology (SMT) is a core assembly technology in PCBA manufacturing, which refers to mounting surface mount components (SMDs) directly on the surface of the PCB and forming reliable solder joints through reflow soldering. Compared with traditional through-hole technology, SMT has many obvious characteristics that make it the mainstream technology in modern electronic manufacturing. One of the most prominent characteristics is high integration and miniaturization: SMDs have a much smaller size and lighter weight than through-hole components, which allows more components to be mounted on a PCB of the same size, greatly reducing the volume and weight of the final electronic product. This is particularly important for portable electronic devices such as mobile phones, tablets, and laptops, which require compact and lightweight designs.

Another key characteristic of SMT is high production efficiency and automation. The entire SMT process, including solder paste printing, component placement, and reflow soldering, can be completed by automated equipment such as stencil printers, pick-and-place machines, and reflow ovens, which not only improves production speed but also reduces human errors. A high-speed pick-and-place machine can mount thousands of components per hour, which is far more efficient than manual or semi-automatic operation. In addition, SMT has excellent electrical performance: the short connection distance between SMDs and the PCB reduces the parasitic inductance and capacitance in the circuit, improving the signal transmission speed and stability, which is crucial for high-frequency and high-speed electronic products. Moreover, SMT has good heat dissipation performance: the surface-mounted components are in close contact with the PCB, which is conducive to heat conduction, helping to reduce the working temperature of the components and extend their service life. However, SMT also has certain requirements, such as high precision of PCB pads and strict control of the soldering temperature curve, which requires professional equipment and technical support.