PCB NC formats

PCB NC drill files convey PCB drilling and routing information. The NC formats were originally designed by CNC drill and route machine vendors as proprietary input formats for their equipment, and are known under their company name: Excellon, Hitachi, Sieb & Meyer, Posalux, etc. These formats are similar as they are based on RS-274-C and related to <a href="/facts/G-code/fAN8mRWf">G-code</a>. In 1985 IPC published a generic standard NC format, IPC-NC-349. Later XNC was designed, a simple strict subset of IPC-NC-349, designed not for driving machines but for exchanging drill information between CAD and CAM. They are collectively referred to as (PCB) NC files.

The NC files are primarily used to drive CNC machines, and they are adequate for that task. 
They are also used to exchange design information between CAD and CAM, for which they are not adequate: essential information such as plating and drill span is missing. Furthermore, the NC output in CAD systems is often poorly implemented, resulting in poor registration between drill holes and copper layers and other problems. To exchange data between CAD and CAM it is more preferred to use the <a href="/facts/Gerber_format/VJLmFm9j">Gerber format</a>. The quality of the Gerber file output software is typically good, and Gerber supports attributes to transfer meta-information such as plating and span.

PCB NC formats open-in-new

PCB NC formats