Fusion360 to G-code

4 minute read

note: this post is linked to this issue, feel at ease to contribute.

How to setup CAM operations in Fusion360

This was a job on PVC Foam like “Forex” in 5mm.
Files was given in .dxf from -Idono-

Step 1 - Import Files

The best is, of course, to create the model directly in Fusion so it keep any parametrics capabilities.

Just Import by uploading, and Open. Easy.

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Step 2 - Checking the model

Yeah, it’s always a good idea to check if the importing module did a good job.

So, in the workspace Model

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  • Is the drawing look fine?
    Is the model have the right size?
    We should be in mm and check the size of the model to be sure. For example, here, we have an object of 2500mm and a board of 500mm (from the customer), so I assume it should be 250mm (not 2.5m)

It’s a common mistake between software, depending in which unit they work.

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  • Rescale and relocate to 0,0 the origin point.

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  • Extrude the sketch to match thickness of material (5mm foam)

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Step 3 - CAM setup

Fusion will use data from the model itself so we kind of need a volume to work from.

I used Rhino and RhinoCam to work directly from curves, I didn't find an easy way to do it in Fusion

  • Switch to CAM workspace to access specific CNC tools.

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  • Setup the origin and work coordinate system depending of your CNC machine.
    You need to match XYZ position and directions with reality.

SETUPS > Setup1 > (rightClick) Edit

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We need to define the “work coordinate system WCS”,
just wait a second over this dropdown menu for details
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I like to use “Select Z axis & something X”
Then I select one edge for Z axis, one edge for X axis (flip if needed) and choose the point of origin.

This will be your 0,0 in your Gcode.

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Watch for stock size. should be Zero Offset everywhere. Just to avoid extra Toolpath around the piece that we don't need in this case.

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Step 4 - Operations

Our objective is to cut the piece but we need 2 jobs for that.
- 1 “contour” job will be inside cutting.
- 1 “contour” job will be outside.

So the piece will not move during the last operation

  • We will choose a 2D operation, > 2D Contour

    In RhinoCAM and some other software, it is called “Profiling”: http://cmu-dfab.org/rcam-2profile/

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  • first, we have to choose which tool we want to use.

Here I’ll use a “spiral bit, 1 flute, 3,175mm (1/8 inch)” for good extraction of chips or dust.
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Depending of the bit, we'll set some feed&speed, which is technical data for rotation speed of the bit, the speed of the tool out and into the material, how fast it goes in and goes out, etc...

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more about Feed & speed: https://cncrouterbits.com.au/technical_speeds_feeds image

  • Select geometry contours (use bottom edges to cut). Leave others by default, that’s ok.
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  • Clearance, don’t touch, default is good enough.

  • Passes, check “multiple depths” to chose passe depth.
    Rules of thumb: Depth max = tool diameter
    We use here 2mm + check “use even stepdowns” to avoid 2+2+1. It will use something like 2,5 + 2,5. That’s ok, just check in the simulation.
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  • uncheck lead in and lead out
    check Ramp. and adjust the Ramping Angle and ramp clearance to avoid to much toolpath and losing time. check in the simulation.
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  • click OK!

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It's always better to make a small square to test separately the settings of feed&speed on the CNC with the actual material.

Simulate

  • To check the result
    just play with the simulation

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GCODE

Gcode is the text who will tell the machine what to do. Like start spindle, go there, go there, now here, and stop, go back to 0,0 and do the harlem shake.

  • To export gcode: right click on the setup or the operation you want to generate > postprocess

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Postprocess will use a specific file who explain to Fusion the right syntax to use to "talk" to your machine. From here, you will need to test on your setup. First slowly then find the sweet spot. Just be careful.

  • name the job and save somewhere.

You can now look at your gcode in a simple notepad, text editor, etc…

Some ref:

  • https://www.youtube.com/watch?v=5EodQIY25tU
  • https://cam.autodesk.com/posts/reference/index.html
  • https://cam.autodesk.com/hsmposts

note: this post is linked to this issue, feel at ease to contribute.