PCB News - What are the factors that cause soldering defects in PCB circuit boards?

What are the factors that cause soldering defects in PCB circuit boards?

In the process of PCB proofing, many soldering defects often appear, which affects the pass rate of the circuit board. So, what are the factors that cause soldering defects on PCB circuit boards?

1. Welding defects caused by warpage. During the soldering process of PCB and components, due to the unbalanced temperature of the upper and lower parts of the PCB, warping occurs, resulting in stress deformation and defects such as virtual soldering and short-circuiting.

2. The solderability of the PCB hole is not good, which will affect the quality of the soldering, and will produce false soldering defects, which will affect the parameters of the components in the entire circuit, resulting in unstable conduction of the components and the inner layer of the multilayer board, causing the entire circuit to fail. .

The main factors affecting PCB solderability are:

(1) The composition of the solder and the properties of the flux. Solder is an important part of the welding chemical treatment process, it is composed of chemical materials containing flux. The function of the flux is to help the solder wetting the surface of the circuit to be soldered by transferring heat and removing rust.

(2) The welding temperature and the cleanliness of the metal plate surface will also affect the weldability. 

 
3. PCB design affects welding quality. Therefore, the PCB board design must be optimized:

(1) Shorten the wiring between high-frequency components to reduce EMI interference.

(2) Components with heavy weight (such as more than 20g) should be fixed with brackets and then welded.

(3) Heat dissipation issues should be considered for heating elements, and thermal elements should be kept away from heat sources.

(4) The arrangement of the components is as parallel as possible, so that it is not only beautiful and easy to solder, it is suitable for mass production; the PCB design is a 4:3 rectangle is the best; the wire width should not change suddenly to avoid wiring discontinuities; should be avoided Large area copper foil.

The above is the factor analysis of PCB circuit board welding defects, I hope it will be helpful to you.