In PCBA processing, solder mask is a very important coating material, which can provide dielectric and mechanical shielding for the PCBA board during the PCBA soldering process and after soldering, and at the same time can prevent the deposition of solder at the soldering position. There are mainly two types of solder films commonly used in the processing of general electronic processing companies: dry film and liquid.

In PCBA processing and SMT patch processing, the solder mask ink is very important. Its main function is to protect the circuit board, prevent the conductor from getting tinned, prevent short circuits caused by moisture and other reasons, and prevent unqualified during processing. The open circuit caused by the contact method can also ensure the normal use of the PCBA board in harsh environments.

However, the above effects are all in the case where the solder mask is relatively good. The solder mask effect is closely related to its design. If the design is not appropriate, it will also affect the solder mask effect. Let us briefly understand the design requirements of the solder mask in the PCBA package processing:

① Connection between pad and through hole: In principle, the wires between the mounting pad and the through hole should be solder masked.

②The solder mask design between the pad and the pad: the solder mask pattern should conform to the design of the solder end distribution of the specific components. If the pad and the pad use the window type solder mask, it will cause a short circuit between the pads during soldering. An independent pin solder resist method is designed between the pad and the pad, which can effectively avoid the short circuit between the pads during soldering.

③Improper size of component solder mask pattern: Oversized solder mask pattern design will "mask" each other, resulting in failure to solder resist, resulting in too small component spacing.

④There are through holes under the components without solder mask, and there is no solder mask under the components. The solder on the holes after wave soldering may affect the reliability of IC soldering, and may also cause defects such as short circuits in the components.

The above content is about the design requirements of PCBA solder mask, I hope it can be helpful to everyone!