Machining Flat Area to Full Depth

I’m using Fusion 360 to do a 3D carving of a warfare device. I’m doing a 3D Adaptive Clearing tool path with 0.5mm stock to leave. This tool path will clear the area directly above the model and also a nice rectangle around the model.

Then I’m using a 3D Parallel Finishing pass to remove the remaining material over the model. I do not want cross hatching in the flat rectangle, so I’m not using this path over there, but it will take the permitter of the model all the way down to the correct level, which will end up being 0.5mm below the flat rectangular clearing.

How do I either make my first tool path not leave 0.5mm “stock to leave” when flat areas can be milled just fine. Or how do I create a 3rd tool path that will just mill that flat area the remaining 0.5mm?

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Creating a 3rd toolpath as a pocketing toolpath, selecting the model perimeter, inverting the selected area (using the red arrow that lets you toggle between carving inside or carving outside the selected vector), selecting “rest machining”, with 0mm axial stock to leave, should do the trick ?

Alternatively you could also restrict the initial roughing toolpath to the model only (i.e. limit the flat area around it to a minimum), and then come back to machine the flat area down to full depth (using a pocketing op as described above). It would still be 3 toolpaths though.


Thanks Julien. Do you know how to efficiently select the model perimeter? If I zoom in and even attempt to click or double click on a perimeter segment, I get a shape that cuts into the surface of the model.

There is the very tedious method of selecting the edges manually: when you auto-select a contour and it’s not the “right” one, you can do a long click on it, and then you can select to add/remove individual segments manually

But that’s really not efficient (or even really doable) in your case with a complex STL shape.

I would probably use a different approach and use another kind of toolpath, like a 2D adaptive clearing rather than a pocket, they have a larger variety of selection options. If you are willing to share your F360 project, I’m happy to take a look and try (or, one of the actual Fusion360 gurus will chime in !)

Do you know the best way to share a Fusion 360 file here? It won’t let me upload the .f3d and the .dxf is just over 25mb (the .f3d is much smaller), so it accepts the file type but seems to instantly abort the upload.

Share a public link:


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Thanks, that model loaded in Fusion360 has my 10-year old PC crawling on its knees, so I can’t answer as quickly as I could have, but I had a thought that you could try if things are faster on your side:

  • go back to Design mode
  • create a new sketch using one of the faces underneath the model (any face should do, since they are all in the same plane)
  • use the Project feature : you should get the outline of the model in that sketch
  • go back to Manufacture tab, and use that outline as the boundary for the outer 2D pocketing

That’s the idea anyway, but I may never be able to test that theory, my PC is sobbing right now :slight_smile:
(I love Fusion, but its performance on large models is…well, awful)

Judging by a quick look at that online the body is close to or above the max number of triangles limit for Fusion360. Performance and editability drop off a cliff on large STLs in fusion.

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haha, sorry for the PC workout. My 8+ year old MacBook Pro can just barely do it. Sometimes I get up and walk away until it finishes thinking. It’s 35,000 facets. Maybe I’ll try to reduce it down some more. It was over 300,000 facets when I started. I want to retain as much detail as I can, but obviously there’s a sweet spot I need to find where only as much detail is retained that could actually be visible on a wood carving.

I’ll try your work around when I get a chance. I’m running G code right now on the same laptop, and I’m certain even opening Fusion 360 might interrupt my Carbide Motion connection/thought process.

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