If you import a drawing from other programs in DXF, it is useful to have a knowledge about the inner process. Have a look at the picture: Often the original is made of many small lines or polygons. Especially with scanning and subsequent vectorizing there is a high rate of "fragmentation" (step 1). Please note that normally the characteristics of a CNC machine is not taken into account when you draw on a piece of paper or construct at the computer - and of course it cannot be expected. Besides that, the vectorizing programs are of very different quality.Therefore re- editing is necessary: With the drawing functions of nccad or with special software the contour has to be corrected resp. simplified. Our terms for it are "contour correction" and "thin out contour" (step 2). A contour that has been worked on in such a way can be machined much better and there is much less communication necessary between PC and CNC-machine.
The following pictures illustrate again the process:
1: Follow contour, to correct gaps and jutting out lines automatically.
2:Thin out contour, i.e. a polygon out of many single parts is transformed into few arcs or lines within certain input limits. 3 and 4: Pocket milling, parallel to contour (3) or parallel to angle (4). The latter can automatically do a finishing run parallel to the contour (see picture in detail).