Want to know what PCB layers stand for ?

A lot of new guys may not know what thePCB layer  means or stand for . Now here you go .

1.Top layer

It’s also called components layer , mainly to be repalced parts . For PCB board , then plays a role of layout . 

2.Mid layer

Normally speaking , maximum 30 layers inside , mainly place signal line .

3. Bottom layer 

Called solder mask layer , mainly to place wiring and weld , sometimes it would also assembly parts on it .

Top overlayer and Bottom overlayer

To remark parts outline , value , position or others you need info . 

4. Solder mask layer 

Including top mask and bottom mask , the layer of PCB file pad and via hole data is generated by protel PCB ,mainly used for laying solder mask. The board uses a negative output, so the pads and vias shown on the board represent the area on the board where the solder resist is not applied, which is where the solder can be soldered.

5. Paste mask Layer

Including top paste mask and bottom paste mask , it is used to correspond components solder join when it goes through oven , but also negative output . The pad and vias shown on the board represent the area of the board where the solder paste is unprinted, which is where no soldering is possible.

6. Drill Layer

- solder mask or not , means appear copper on the PCB or not

-paste is to make stencil

So when we draw the board , the two layers have to be drawn .

After all of the layers , here is one PCB Assembly photo for your reference .

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Hope this could help you a lot .