Path: how the OpFinalDepth variable is calculated?

[nicokid]

Hi all,
I still don't understand how the OpFinalDepth variable is calculated.
It seems to be set on the highest point of the surface. For example if I have a 4.5 mm high plate and create a profile (i.e. I want to make a through hole) OpFinalDepth is set to 4.5 mm.

Am I doing something wrong? Do I always have to change it by hand? What is the correct way?

Thanks.
Nicola.

[chrisb]

Perhaps you are milling from behind? Positive Z points upward in the direction of the mill.

[nicokid]

Yes, the Z axis is positive in the direction of the spindle.
Pockets go in the correct direction.

Thanks.

[chrisb]

If you have selected Profile from Face on the top face then the profile works just down to this face. If you want it to profile to the bottom, select something from the bottom, be it a path or a face.
For further studies you may upload your file.

[nicokid]

Hooray!
I rotated my plate upside down and selected the holes from below.

test_freecad.FCStd

Arduino plate

(43.26 KiB) Downloaded 24 times

Ok maybe it was logical to select the objects below, but unfortunately I had not yet reached it

Many thanks chrisb

Nicola.

[chrisb]

You're welcome. I am a bit surprised about the zigzag rapid moves between the holes. The space between SafeHeight and ClearanceHeight should be kept free of horizontal moves to allow clamping.

[nicokid]

Yes you are right. SafeHeight and ClearanceHeight are very low.
I do it to speed up milling. My cnc Stepcraft 840 is not so fast on the Z axis. to prevent the impacts of the tool I clamp the workpiece on the outer edge.

Nicola.

[chrisb]

No, it's not your partameters I'm talking about. It may be an error in the Path workbench. I think the rapid moves should go straight at safe height.

[onekk]

Me too, in CNC work usually Positive means UP, and Negative Down, inverting the logic is confusing.

Aat least in the usual conventions tha seems to be used also in FreeCAD:

https://wiki.freecadweb.org/Template:Depths/Heights

Regards

Carlo D.

[chrisb]

Me too, in CNC work usually Positive means UP, and Negative Down, inverting the logic is confusing.

There is nothing inverted. If you have a model with the upper surface at z=0 you mill down into the material by going e.g. to z=-10, which is negative.