Divots at entry and exit

I am curios if anyone can tell me why my entry and exit points are not clean.

  • It does NOT appear to be an issue with the Gcode.

  • The problem is more pronounced toward the top of the workspace.

  • I watched it closely. The XY travel path is smooth. The notches are created AS it is plunging and retracting. Almost as if the bit is entering at an angle, yet once fully extended it cuts as expected.

Any advise or speculation is welcome. Many thanks. Ed

Hi, I guess flat endmills are not perfect tools for drilling…so going straight down too fast may cause vibrations.
I guess you could try reducing the z-axis feedrate, or use ‘ramped entry’ instead of vertical plunge (if your CAM-software have an option for that).

I don’t know which other CAM software support this, but I know KrabzCAM does…

Good luck :slight_smile:

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do your endmills have a continuous cutting surface on the bottom? If not (and
not all do), you can be in a situation where the bit can’t fully remove the
material when plunging directly and as a result it wobbles a bit on the part
that’s not cut (which moves it to where that does get cut)

As noted below some CAM software offers an option to avoid direct plunge cuts
and instead ramp down.

David Lang

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