What are the factors causing soldering defects on PCB?
In the process of PCB proofing, we often have many welding defects, whICh affect the qualification rate of PCB. So, what are the factors that cause soldering defects on PCB?
1. Welding defects caused by warping. During the welding process of PCB and components, warping occurs due to the unbalanced temperature of the upper and lower parts of PCB, resulting in stress deformation and defects such as false soldering and short circuit.
2. The poor solderability of PCB holes will affect the welding quality, resulting in faulty soldering defects, which will affect the parameters of components in the entire circuit, leading to unstable conduction of components and inner wires of multilayer boards, and causing the functional failure of the entire circuit.
The factors affecting PCB solderability mainly include:
(1) Composition of solder and properties of flux. Solder is an important part of welding chEMIcal treatment process, which is composed of chemical materials containing flux. The function of the flux is to help the solder to wet the circuit surface of the soldered board by transferring heat and removing rust.
(2) The weldability is also affected by the welding temperature and the cleanliness of the metal plate surface.
3. PCB design affects welding quality. Therefore, PCB design must be optimized:
(1) Shorten the connection between high-frequency components to reduce EMI interference.
(2) Components with large weight (such as more than 20g) shall be fixed with supports and then welded.
(3) Heat dissipation shall be considered for heating elements, and thermal sensors shall be far away from heat source.
(4) The arrangement of components should be as parallel as possible, which is not only beautiful, but also easy to weld, so it is suitable for mass production; The best PCB design is 4 ∶ 3 rectangle; The wire width shall not change suddenly to avoid the discontinuity of wiring; The use of large areas of copper foil should be avoided.
The above is the explanation given by the editor of pcb circuit board company. If you want to know more about PCBA, you can go to our company's home page to learn about it. In addition, our company also sells various circuit boards,
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