1. The various design elements that make up a PCB should be described in the design drawings. The appearance is represented by Mechanical 1-16 layers (priority) or Keep out layer. If used simultaneously in the design file, generally keep out layer is used to prohibit wiring without opening holes, and mechanical 1 is used to indicate forming. In the design pattern, indicate a long SLOT hole or hollow, and use Mechanical 1 layer to draw the corresponding shape.

　　2. Dimensional tolerances for PCB board samples

　　The overall dimensions of the PCB should comply with the provisions of the design drawings. When there is no specification in the drawing, the tolerance of the external dimensions is ± 0.2mm.

　　3. Flatness (warpage) 0.7%

　　(4) The concept of layers

　　1. If a single panel draws a signal layer on the top layer, it indicates that the circuit on that layer is the front view.

　　2. If a single panel draws a signal layer on the bottom layer, it indicates that the circuit on that layer is a perspective surface.

　　3. Our company defaults to using the top layer (i.e. the top layer) as the front view for double-sided boards, and the characters on the top overlay silk screen layer are positive; The bottom layer (i.e. the bottom layer) is the perspective surface, and the bottom overlay screen printed characters are reversed;

　　4. The multi-layer board lamination sequence is based on the layer stack manager for the protel99se version. For versions below protel98, identification or software sequence should be provided. For pad series design software, sequence should be used.