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I used splines in my CAD drawing but the g-code only uses arcs--how do I get splines in the g-code?


I have part for milling link below. Its simple milling. I have designed surface using spline. I have also tried with non-standard curves. But when post process it, i got G-Codes in form G02 and G03 which means use of circular interpolation and is an indication of presence of primitive geometry. I am sure i have made it with spline and curves then why in post process i got G02 and G03. I want to have just X and Y numbers and i dont mind if it include some i and j. But G02 and G03 not acceptable. Anyone can help me?

I have UG NX and 3-axis mill.


LINK to geometry (virus Free, scan by AHN – my personal dropbox):



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Best Answer

Most controllers on CNC machines only support arcs–no splines.  Even those that do support the splines often do so as an extra-cost option.  Not all CAM software can take advantage of controllers that offer spline support.  For the ones that do, you will need a postprocessor that is set up to take advantage of the splines using the g-code syntax your controller expects.

If you don’t have all that, then the CAM software will attempt to simulate the spline using lines and arcs as best it can.

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