What is a solder mask?

Today, little Bo went to work after the company's front desk, saw the new front desk little sister Manman where to scratch her head and ears, the warm-hearted little Bo took the lead to help. The original customer calls to consult welding resistance, for just entered the small white may still be some unclear.

So what exactly is a solder mask?

The solder resistance layer is, on the surface, a layer of solder resistance material on the circuit board for the purpose of dividing the areas that need to be welded and not welded. Reflow welding is an important part of SMT assembly, which makes electronic components pass through the solder paste device on the circuit board. The solder stop layer prevents the welding bridge from occurring in the covered area, so that more precise components can be welded to the precision pad. If the solder mask is not applied, the copper trace will adhere to the solder paste. This happens with many hand-built circuits. It can also cause a short circuit, which affects functionality and reliability. In fact, the solder mask has other functions, such as insulation, temperature resistance and corrosion resistance, protection of the line, prevention of oxidation, matching thickness and so on.

We usually divide the solder resistance layer into solder resistance and solder resistance film, which is a thin layer that covers the copper trace.

Solder resistance is generally used in hard PCB, most of the color is green, so we are generally used to call it green ink layer (referred to as: green oil layer). In fact, it can also be deployed into other colors of flux resistance, such as white, black, yellow, blue, red, etc., with the improvement of the market team's aesthetic requirements, more and more colors of flux resistance are applied to circuit boards. Ink is the use of screen printing process, the ink is printed on the circuit board, after curing treatment tightly attached to the PCB board.

The flexible circuit board (flexible PCB) because of the soft characteristics of its substrate, generally use solder resistance film, there are many kinds of colors, common transparent, yellow, white, black. This use of polyimide as the primary material, low temperature class is called PET, high temperature resistance is called PI, it is very good in insulation, moisture resistance, high temperature resistance and welding resistance. The covering film is cut by laser and pressed by vacuum, so that the film is tightly pasted on the copper-covered plate (flexible circuit board substrate).

In short, whether it is ink agent or covering film, it is divided into a variety of specifications according to the material, function and thickness. Our engineers will design high-quality PCB and flexible circuit board according to different program requirements, using the corresponding materials.