Creating CNC roughing and finishing passes

[prius06]

Hi guys,

I am very new to CAD and CAM, so please forgive me if I am asking questions that sound stupid or may have been answered before. I built a CNC machine. Well, I actually bought a frame and connected it to an Arduino Uno flashed with grbl. Now I can finally play with designing small objects and cutting them out of wood or plastic and most recently out of machinable wax...

What I am trying to do next is to create several paths starting with a larger tool for rough shaping and when I get withing a mm or so from the final creation switch to a smaller end mill for a finishing pass that should look similar to this video https://www.youtube.com/watch?v=lqAkY9mBA4U

For that purpose I started with a cube and a semi-sphere attached to it and tried the various paths available in the path workbench but they all created lots of passes with fixes Z axis and cutter moving strictly horizontally. I would like the finishing pass move end to end in a zigzag pattern while the Z axis follows the relief (just like in the video above).

Sorry I am not using the right terminology but as I said before, this is all very new to me.

Thanks for developing FreeCAD and hope to join you one day. I am actually a software engineer but my professional work is completely unrelated to CAD and CAM software.

[prius06]

I think I almost found what I was looking for...

I enabled path experimental features as described here: https://www.freecadweb.org/wiki/Path_experimental
And finally saw the 3DSurface as a Path option. The drop-cutter pattern seems to be what I was asking for but there is still one thing that I am missing in this path - the ability to set overlap (step over percent).

Is there a way to define overlapping between the multiple passes the cutter is doing?

Thanks!

[sliptonic]

I think I almost found what I was looking for...

I enabled path experimental features as described here: https://www.freecadweb.org/wiki/Path_experimental
And finally saw the 3DSurface as a Path option. The drop-cutter pattern seems to be what I was asking for but there is still one thing that I am missing in this path - the ability to set overlap (step over percent).

Is there a way to define overlapping between the multiple passes the cutter is doing?

Thanks!

Not from the task panel but there's a step-over percent property.

snap1.png (59.22 KiB) Viewed 1863 times

[prius06]

Is this new?

All I have in my version (13528 (Git)) under Surface is "Sample Interval"

[sliptonic]

Ah. You didn't include your freecad info but I should have assumed you might be using the 0.17 release. What I showed is in the current development branch for 0.18. Sorry.

[prius06]

Ah. You didn't include your freecad info but I should have assumed you might be using the 0.17 release. What I showed is in the current development branch for 0.18. Sorry.

That's fine. Are there plans to release that soon? If not, is the dev branch available as windows installable?

Thanks

[sgrogan]

That's fine. Are there plans to release that soon? If not, is the dev branch available as windows installable?

We are hoping to release 0.18 by the end of the year.
No installer, but there are portable builds available: https://github.com/FreeCAD/FreeCAD/rele ... g/0.18_pre
Just unzip the file (you'll need https://www.7-zip.org/) and run FreeCAD.exe from the bin sub-directory of the extracted directory. The dev version can exist side by side with 0.17 installed version.
A request would be to use the py3 version "FreeCAD_0.18.14451_Conda_Py3QT5-WinVS2016_x64.7z" to increase PY3 testing/bug-reporting, but a PY2 version is also available "FreeCAD_0.18.14451_x64_dev_win.7z" The exact version is updated regularly.

[chrisb]

That's fine. Are there plans to release that soon? If not, is the dev branch available as windows installable?

https://github.com/FreeCAD/FreeCAD/rele ... g/0.18_pre
0.18 seems to be as stable as 0.17. The release is due end of the year, no exact date is fixed yet.

Edit: hadn't seen that sgrogan had already answered.

[prius06]

Thanks very much for the help!

[prius06]

I guess I am getting closer but... now I am getting
"This operation requires OpenCamLib to be installed"

And based on the Github instructions I have to rebuild it after installing Python .... and Boost...

Is there a shortcut to get the ocl.pyd from somewhere so it can be installed in Freecad?

Thanks