1,SMT

• Solder paste printing is the first step of PCBA. The solder paste is accurately coated on the PCB pad with screen printing. Solder paste is used as a medium to connect the pins and pads of electronic components in the subsequent welding, and its printing accuracy affects the welding quality of mobile phone circuit board components.

Component mounting and reflow soldering:

• The surface mount components are accurately placed on the PCB pad, which can process a variety of components at high speed and high precision. The chip capacitance and resistance of the computer motherboard are installed from this. After the mounted circuit board is reflow soldered, the solder paste melts and solidifies, so that the pins of components and pads are soldered firmly. Temperature control is required to ensure quality and prevent virtual soldering and short circuit.

2,DIP

• Plug-in: For components that cannot be installed by surface mount technology (such as large electrolytic capacitors, transformers, etc.), insert the pins into the corresponding holes of the PCB board by hand or by a plug-in machine.
• Wave soldering: The PCB board inserted into the component passes through the wave soldering equipment, and the pin contacts with the wave peak formed by the melting solder in the equipment to complete the welding.

3. Detection and debugging phase

• Appearance inspection: manually or using Automatic Optical Inspection (AOI) equipment, check whether the installation position of the components on the circuit board is correct, whether the welding is good, and whether there are obvious defects such as short circuit, open circuit and missing parts.
• Electrical performance test: use professional testing equipment.