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 G-code. 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
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
IPC-NC-349 format
[edit]The IPC-NC-349 format is the only IPC standard governing drill and routing formats.[5] XNC is a strict subset of IPC-NC-349, Excellon a big superset. Many indefinite NC files pick some elements of the IPC standard.[1]
A digital rights managed copy of the specification is available from the IPC website, for a fee. It is targeted at input for drill/rout machines, not
XNC format
[edit]The XNC format is strict subset of the IPC-NC-349 specification targeted at data exchange between
The specification is freely available among others at the Ucamco download page. The specification is brief, detailed, easy to understand and unambiguous. It is targeted at
An example:
M48 Start of header
METRIC Metric units (mm)
T01C0.6 Tool 1 has diameter 0.6mm
T02C1.0 Tool 2 has diameter 1.0mm
% End of header
G05 Set drill mode
T01 Select tool 1
X8.5Y4.8 Drill a hole of 0.6 mm at coordinates 8.5mm,4.8mm
X8.55Y2.85 Drill
X6.54Y2.85 Drill
X6.45Y4.8 Drill
T02 Select tool 2
G00X10.25Y3.825 Move to coordinates 10.25mm,3.825mm
M15 Plunge rout tool down
G01X6.50Y3.25 Rout to coordinates 6.5mm,3.25mm
M16 Lift rout tool up
M30 End of file
Excellon format
[edit]The name Excellon format is derived from the company Excellon Automation (not to be confused with Excellon Software), which was the market leader in PCB drilling and routing machines during the 1980s, and whose proprietary format became widely used.
There are actually two Excellon formats, the older Excellon 1 and Excellon 2. Excellon 2 is a superset of IPC-NC-349. Commands from both are sometimes confusingly mixed in the same file.
Excellon Automation stopped publishing the specification of its format, without statement on the IP and usage rights of the format. An archived copy exists.[8] The specification is ambiguous, leading to different interpretations, especially in the area of coordinates and units. It is targeted at input for drill/rout machines, not
Indefinite NC files
[edit]An example:
%
T01
X006272Y001092
X006354Y001093
X006653Y001092
...
T02
X008091Y001754
X-002028
M30
The tool diameters and how to interpret the coordinates is not specified. This file is meaningless without additional information, typically put in a free format human readable tool file. This information must be re-entered manually by the
See also
[edit]- Gerber format – Standard file format used for designing printed circuit boards
- EDIF – file format
- STEP (file format) – A widely used
CAD 3D data exchange file format
References
[edit]- ^ a b c Charras, Jean-Pierre. "XNC Format: Gerber Takes Data Into the Future" (PDF). Retrieved 7 April 2019.
- ^ "PCB Layout Data". Eurocircuits. Archived from the original on 6 December 2011. Retrieved 26 November 2011.
- ^ ""Gerber Format Specification"" (PDF). Ucamco.
- ^ Tavernier, Karel. "PCB Fabrication Data - A Guide - section on drill files" (PDF). Retrieved 16 January 2015.
- ^ IPC-NC-349 Computer Numerical Control Formatting for Drillers and Routers, published in 1985
- ^ "
CAD software firms develops XNC format for PCB drill date". pcdandf. Retrieved 26 February 2019. - ^ "XNC file format specification". Ucamco. Retrieved 26 February 2019.
- ^ "Former Excellon format description". Archived from the original on 2007-10-30. Retrieved 2007-10-30.
External links
[edit]- IPC-NC-349 specification (payable)
- XNC format specification
- Former Excellon format description (archived from the original on 2007-10-30)
- PCB Fabrication Data - A Guide