Your problem is probably more to do with your software converting 3d data to 2d "Splines". Not sure of your process or software, but if you list the entities in the cad software before export as dxf - Avoid "Splines" - Use Lines, Arcs, Polylines (Lwpolylines) etc. Your Dxf and resultant Gcode files should also be smaller.
(I assume that because your cam program happy with spline, also happy with polylines. Some only accept lines/arcs)
If it helps, the process I use is
1) generate the drawing from the 3d model in the 3d modelling software.
2) delete all extraneous entities in a 2d cad program, and list / convert entities as required. try to avoid splines (solidworks often creates splines from section views), as you generally need to trace over them to get something usable.
3) your resultant export as dxf should be good now in all versions of dxf (depending on cam setup).
I hope this helps