Are all the edge holes of PCB production boards used for positioning? Not all. There is also a row of holes arranged from small to large, called the first hole, which is used for detection. Some companies will also add other holes, mainly to cooperate with production equipment. Because the plate edge is finally milled off, the holes on the plate edge are basically auxiliary holes.
 
There are many kinds of PCB plate edge positioning holes.

1. Riveting positioning hole: used to prevent deviation of PCB plate during pressing.

2. Drilling positioning hole: for positioning during drilling.General X-ray fluoroscopy drilling.

3. PTH and copper plating inspection hole: it is used to inspect the copper integrity of the hole during production. It is drilled out of a borehole.

4. Outer line positioning hole: used for outer line film positioning. It is drilled out of a borehole.

5. Solder resist positioning hole: used for solder mask positioning. It is drilled out of a borehole.

6. Text positioning hole: used for text positioning. It is drilled out of a borehole. It can be shared with other holes.

7. Secondary drilling and milling plate positioning hole: used for secondary drilling and milling plate positioning. Drilled out of a borehole.It can be shared with other holes.

In the above, the positioning hole of general PCB production process is considered, and the special processing plate is not considered, such as HDI board, laser positioning film processing, laser drilling board, etc.