What is solder resistance in the multilayer circuit board manufacturing process? What is welding aid? And what’s the difference between the two? In general, the welding layer is mainly to prevent

the direct exposure of multi-layer circuit board copper foil in the air, play a protective role, and the welding layer is used for steel mesh, and the solder paste can be accurately placed on the patch pad

that needs to be welded when tin is applied.

The difference between solder resist layer and solder aid layer of multilayer circuit board

Solder pad is, refers to the PCB board on the part of the green oil. In fact, the solder mask uses a negative output, so after the shape of the solder mask is mapped to the board, it is not a green oil

solder mask, but a copper skin is exposed. Usually in order to increase the thickness of the copper skin, the green oil is marked on the solder resistance layer, and then tin is added to achieve the

effect of increasing the thickness of the copper wire.

The welding layer is used when the machine is placed, corresponding to the welding pad of the patch component, in SMT processing, a steel plate is usually used to punch holes on the PCB

corresponding to the welding pad of the component, and then the solder paste on the steel plate, when the PCB circuit board is under the steel plate, the solder paste leaks down, which means that

each solder pad can be stained with solder. Therefore, usually the solder mask can not be larger than the actual size of the pad.

Multilayer circuit board welding layer and welding resistance layer difference

Both layers are used for soldering, not referring to one on tin and one on green oil, but:

1. Welding aid layer is used for patch packaging.

2. By default, green oil should be applied to areas without solder resistance layer;

3, the solder resistance layer means that the window is opened on the green oil of the whole piece of solder resistance, in order to allow welding;