Professional Electronic PCB Circuit Board, PCBA and PCB Assembly

What is solder mask PCB?

PCB is basically composed of pads, vias, solder mask, silk screen layer, copper wire, etc. This article will analyze solder mask. What is solder mask? What is the role of solder mask?
The solder mask refers to the part of the PCB that is covered by ink. Since most PCBs use green ink, the part of the green ink that can be seen is the solder mask. The role of the solder mask during PCBA Manufacturing's control of the reflow soldering process is very important. important.
In terms of solder mask material, it must be used through liquid wet process or dry film lamination. The dry film solder mask material is supplied in a thickness of 0.07-0.1mm (0.03-0.04″), which can be suitable for some Surface-Mount (SMT) &BGA Assembly products, but this material is not suitable for the denser pitch PCB.
Solder mask is divided into 3 types:
Spot welding: The weldment is pressed between two cylindrical electrodes, energized and heated, so that the weldment melts at the contact point to form a nugget, then the power is cut off, and solidifies and crystallizes under pressure to form a dense welded joint. Spot welding is suitable for welding thin plates (lap joints) and steel bars below 4 mm, and is widely used in the production of automobiles, airplanes, electronics, instruments and daily necessities.