Making Files for NC Cutting

Companies that cut sheet metal or other sheet material generally require data in proprietary formats. The interchange is not always as simple as it might be. The commonest interchange format is DXF.

The starting point for my data was a series of vector files. These were easily converted to pdf files. Pstoedit converts these easily to clear DXF files.

What looked like an easy task mutated into a time wasting monster: the DXF output from pstoedit was not suitable for laser cutting, since lines and therefore laser head movements are more complex than necessary.

My next attempt was to generate DXF files using the description of published by Autocad. This produced files which were read by librecad, but not by DraftSight which is used by many of the cutting shops. Rewriting the file using Librecad did not help. DraftSight hung on these too.

What became apparent is that DXF files conform to a frighteningly great many standard versions.

What worked to solve this problem was ezdxf by Manfred Moitzi. This proved to be very easy to install and use (under the MIT license), and produced files which could be read by DraftSight.

DraftSight proved to difficult to install. The opening message window said modules could not be found. This sidetracked me into trying to find unresolved dependencies. This was not the issue. Executing the program from its install directory resolved the matter. Opening the HelpGuide file started Qt5 Assistant but with no information.

DraftSight works quite well, but has onerous license conditions. It is not clear why DXF files from librecad can not always be read by DraftSight.