The circuit board includes many types of working levels, such as signal layer, protective layer, screen printing layer, internal layer, etc., the role of various levels is briefly described as follows: ⑴ signal layer: Mainly used to place components or wiring. Protel DXP typically contains 30 intermediate layers, Mid Layer1~Mid Layer30, which is used to decorate signal lines, and the top and bottom layers are used to place components or apply copper.

⑵ protection layer: Mainly used to ensure that the circuit board does not need tin plating place is not tin plating, thus ensuring the reliability of the circuit board operation. Among them, the top Paste and Bottom Paste are the apical resistance welding layer and the bottom resistance welding layer respectively. Top Solder and Bottom Solder are the protective layer of solder paste and the protective layer of bottom solder paste respectively.

⑶ screen printing layer: Mainly used in the circuit board printed on the components of the flow number, production number, company name and so on.

⑷ internal layer: Mainly used as a signal wiring layer, Protel DXP contains 16 internal layers.

⑸ Other layers: mainly includes 4 types of layers.

Drill Guide (Borehole azimuth): Mainly used in the location of boreholes on printed circuit boards.

Keep-Out Layer (Prohibited wiring layer): Mainly used to draw the electrical border of the circuit board.

Drill Drawing (drilling drawing layer): Mainly used to set drilling shape. Multi-Layer (Multilayer): Mainly used to set up polyhedron layers.