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Fusion 360 multiple tool retracts

AndrewOrme

Plastic
Joined
Jul 27, 2020
Hello all, I am a mechanical engineer with lots of 3D design experience but I lack on the CAM side of things. I am using Fusion 360 to create a tool path for a mold. Tools range from between .007 and .035 flat end mill and ball end mill so it is a very small part. I'm using 3D adaptive for the tool path.

When creating the tool paths the tool retracts many many times. See yellow lines on attached. I have the LINKING at minimum retraction and STAY DOWN LEVEL at most. Any solutions/suggestions would be great.

Thanks
multiple retracts.jpg
 
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In my experience when I get something like that (lots of unnecessary rapid moves) I am trying to use the wrong toolpath. 3D adaptive is a nice roughing strategy, but not a panacea. Since it starts with the assumption it will machine everything, everywhere, and then must be constrained, for simple geometry it is often better to use the 2D adaptive and tell it exactly where you want it to put in work. The AD forums are super helpful if you can share the project.
 
Hi Rick, thanks for your input. That makes sense. Would you mind taking a look at this pic? As this pocket changes geometry as you go deeper, I thought that 2D wouldn't work. Do you think there is a way to make 2D work with this pocket?GEOMETRY.jpg
 
3D vs 2D operations are correct for that part. Is that your initial rough or the re-rough operation - calculating a smaller tool from rest machining from previous operations?
 
Speaking of rest machining. Could clarify something for me? The pop up window explains that "rest machining limits the operation to only remove material that a previous tool or operation could not remove". Suppose my first operation is a rough out and I leave .01 for the finish cut but there are also some areas that the tool could not reach (there might be .02 left) because it was too big. If I check the rest machining box, and assuming my finish tool is small enough, will my finish tool/operation cut both the .01 that I purposefully left for a finish cut AND the other areas that the first tool could not reach?

OR

Will it only machine the areas that the first tool could not physically reach because it was too large? Does that make sense?
 
Don't know fusion, so may not apply. Sometimes on 3d paths the tool simply can't stay down because cutting one direction, or needs to clear 'high' spots in the 3d form areas. As to your rest machining question, I would tell the rest machining to leave the same stock as your rough and it should theoretically not touch anything but the stock that could not be removed*

*Cam softwares process differently so I would verify this behavior before ass-u-ming it will work like that.
 
I would start by breaking that up into a couple of different tool paths. The top 45 degree angle surfaces and radii grooves with a horizontal, the angled walls with a Z level, and the bottom channel with another horizontal.
 
That is going to require 3D adaptive for roughing in Fusion in one toolpath. That said, I would likely break it down into a few different toolpaths. What is the material? Looks like a good candidate for high feed milling at low stepdown and a 3D adaptive path, followed by breaking down the semi-finish and finish passes into several toolpaths.
 
Thanks all for your comments. I was able to use 3D adaptive for the rough out and then switched to parallel for the deep parts and the finish. However now I have a new problem. My machine doesn't like something about the code. I get an error that says "circle end error" code. I've read the following but have not found any answers? This can be caused when using scaling when cutting arcs and the X and Y scale values are not equal. Can also be caused by the radius at the end point of a circle is not the same as the radius at the start or the XY end point is not on the radius of the arc. "If this error occurs with cutter compensation but not without it, a change in compensation was followed by a circular move instead of a linear move as required".

Any ideas? Thanks
 

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Thanks all for your comments. I was able to use 3D adaptive for the rough out and then switched to parallel for the deep parts and the finish. However now I have a new problem. My machine doesn't like something about the code. I get an error that says "circle end error" code. I've read the following but have not found any answers? This can be caused when using scaling when cutting arcs and the X and Y scale values are not equal. Can also be caused by the radius at the end point of a circle is not the same as the radius at the start or the XY end point is not on the radius of the arc. "If this error occurs with cutter compensation but not without it, a change in compensation was followed by a circular move instead of a linear move as required".

Any ideas? Thanks

Just a couple WAG here so take with a grain of salt...

Haas machines won't take a cutter comp move on a G2/G3 arc move, you need a straight G1 move, with a minimum move of your comp. If using wear comp, this is never much of an issue, but if you are using control comp you need a lead in/lead out at least equal to tool radius, plus a bit more if you plan on comping more than a couple thou.

On an older Charmilles I ran it used IJK for rad moves and if they mismatched even .0001" it would not run.

One other thing you might want to check if the comp is turning off when moving back to center.
 
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