Talking about the precautions of mounting and soldering of SMT components

In SMT mounting processing, there are many types of components, among them that chip components are the key to SMT assembly welding technology, which has an impact on product quality and reliability. The chip components are microelectronic components, and there are many types of models. The shapes are different and the physical properties are different. Pay attention to the following matters during mounting and soldering:

1. Before welding, you need to know whether the components have special requirements, such as welding temperature conditions, assembly methods, etc. Some components cannot be soldered by immersion soldering, and can only be soldered with soldering irons, such as chip potentiometers and aluminum electrolytic capacitors, so you need to choose the correct soldering method depending on the situation.

2. For components that require immersion soldering, it is best to dip them only once. Multiple immersion tin will cause the printed board to bend and the components to crack.

In the SMT mounting and soldering process, in order to prevent static damage to the components, the soldering iron and soldering furnace used should have good grounding devices.

For the selection of printed boards, the thermal deformation should be small, and the copper foil should be covered with great force. Since the surface-assembled copper foil has a narrow trace and a small pad, if the peeling resistance is insufficient, the pad is easy to peel off, and an epoxy glass substrate is generally used.

5. for rectangular chip capacitors, the use of larger appearance ones, such as 1206 type, easy to weld, but due to uneven welding temperature, prone to cracks and other thermal damage; the use of smaller appearance, such as 0805 type, although Welding is difficult, but cracks and thermal damage are less likely to occur, and reliability is high.

6.If the PCB board needs to be repaired, the number of component disassembly and assembly should be reduced as much as possible, because frequent disassembly and assembly will lead to the complete scrapping of the printed board. In addition, for printed boards that are mixed, such as inserting components that hinder the disassembly and assembly of the chip components, they can be removed firstly.

In the SMT mounting processing, the welding of the chip components is very complicated. The operator should learn the welding techniques and understand the precautions, carefully operate to avoid errors or affect the welding quality.