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FAST TURN PCB is a circuit maker specializing in PCB manufacturing and assembly, with excellent and quick turn PCB fabrication and circuit card assembly capabilities.

What are each layer in a PCB circuit? What is its purpose?

In the field of electronic engineering, printed circuit boards (PCBs) are indispensable components that carry the connections and communication between electronic components. PCBs are not single-layer structures, but are composed of multiple layers, each with its specific functions and roles. Let’s talk about them together.

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1. Mechanical layer
Definition: The mechanical layer represents the overall appearance and size of the PCB board.
Function: It defines the boundaries, dimensions, assembly instructions, and other information related to mechanical characteristics of the circuit board.
Usage precautions: The mechanical layer is often output and displayed together with other layers, but should not be used for electrical wiring.

2. Keep Out Layer
Definition: This layer defines the areas on the PCB board that allow for wiring or placement of components.
Function: By drawing enclosed areas, boundaries are set for automatic layout and routing to ensure the effectiveness of circuit design.
Usage precautions: The wiring layer should not be confused with the mechanical layer, and its boundaries define the scope of electrical wiring.

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3. Signal Layer
Definition: The signal layer is the area on a PCB board used for arranging wires, including the top layer, bottom layer, and middle layers.
Function: The top and bottom layers are usually used to place components, while the middle layer is used for wiring, achieving electrical connections between components.
Layer count: According to design requirements, a PCB can have multiple intermediate layers for complex wiring designs.

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4. Top Paste and Bottom Paste
Definition: These two layers represent the top and bottom layers of the solder pad steel mesh.
Function: In SMT (Surface Mount Technology), the Top Paste and Bottom Paste layers are used to make steel mesh, ensuring uniform application of solder paste and optimizing the welding process.
Application: The holes on the steel mesh match the size of the solder pad, ensuring that the solder paste can be accurately applied to the solder pad.