What are the common bad causes of PCBA solder mask?
2023-12-12
Solder mask is an important coating material in the processing of PCBA, which can provide dielectric and mechanical shielding for PCBA boards during and after PCBA soldering, and prevent solder from being deposited at this location. There are two types of solder films commonly used in the processing of electronic processing plants, liquid and dry films.
Solder mask ink is very important in PCBA processing and SMT chip processing, its main role is to protect the circuit board, prevent the conductor from tinning, prevent short circuit caused by moisture and other reasons, prevent the open circuit caused by unqualified contact mode in processing, etc., and is one of the reasons to ensure that the PCBA board can be used normally in harsh environments. The following is a brief introduction to the poor design of solder mask film in PCBA contracting:
1. The pad is connected to the via. In principle, the wires between the pads and the through holes should be soldered.
2. The solder mask design between the pad and the pad, the solder mask graphic specification should be in line with the design of the specific component solder end distribution: if the windowed solder mask is used between the pad and the pad, the short circuit between the pads during soldering is caused by the windowed solder mask, and the pin independent solder mask mode is designed between the pads and the pads, and there will be no short circuit between the pads during soldering.
3. The size of the solder mask pattern of the components is improper, and the design of the solder mask pattern is too large, which will "mask" each other and lead to no solder mask, so that the spacing of the components is too small.
4. There is no solder mask film under the vias, there is no solder mask under the components, and the solder on the vias after wave soldering may affect the reliability of IC soldering, and may also cause defects such as short circuit of components.
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