Tooling hole of PCB refers to determining the specific position of PCB through hole in the PCB design process,
which is a very important in the PCB design process. The function of the locating hole is the processing datum when the printed circuit board is made.
PCB tooling hole positioning methods are varied, mainly according to different accuracy requirements. Tooling hole on printed circuit boards shall be
represented by special graphical symbols. When the requirements are not high, the printed circuit board can also be used to replace the larger assembly hole.
The tooling hole is usually designed as a non-metallic hole with a diameter of mm. If you do a panel board, you can think of the panel board as a PCB, the whole panel
board as long as there are three positioning holes.