2D contour issue

[Anonymous]

I'm having some weird issues with some very simple 2D contour ops and I can't quite figure out where I'm going wrong. It seems to be when I turn on "in control" compensation.

It's these 4 chamfers here.

If I select one chamfer it works fine.

But when I select all 4 chamfers it adds a little bulge to each one which isn't in the model, and even when I just draw a circle and select that as the contour it does it.

And sometimes when I do it skips one contour and tells me that it can't do it because the given lead would cause a collision. I have compared this op and the other op where it works on all four and it says there is no difference between them.

If I don't add a tip offset it actually joins them together.

[david.lundbergC7AM5]

Looks to me like it machines the wrong side of the contour...

Tried clicking the red arrows? 

[Anonymous]

They are on the correct side.

[seth.madore]

I have seen this error before, it's something to do with how the toolpath is calculated and drawn in the backend of things. Can you share your file? File > Export > Save to local folder, return to thread and attach the .f3d file in your reply.

Is it 100% needed to run "Control Comp"?

[Anonymous]

It's easier for me to use control comp, I can get around the issue by splitting it up into two ops and doing two holes diagonally opposite, but I have done a bunch of similar parts recently and it's worked fine on all of them.

[engineguy]

@Anonymous 

@seth.madore 

@david.lundbergC7AM5 

Hope you all don`t mind me joining in here, but I don`t think this is actually a "bug" as such, more a case of Fusion doing one of it`s "thinking for the dummies" where we as users have done something that we shouldn`t Fusion very kindly changes things for us, it can be quite "picky" 🙂 🙂

Anyway, to what is happening, most of the time we will get away with it but when we try to have toolpaths too close together and when we go to "Control" compensation the tool paths would intersect as this is obviously bad Fusion changes them to not intersecting, very good of it to be sure 🙂

The solution? Very simple, just use a smaller tool, I changed the 8mm 45deg tool to a 3mm 45deg and it works fine, I didn`t try anything else so you will just have to do a little trial and error to find the biggest tool  that will work, or if you are fine with the 3mm 45deg then go for it:) Modified file attached!

Regards

Rob

[engineguy]

@Anonymous 

@seth.madore 

@david.lundbergC7AM5 

P.S. I just tried some different size tools and the biggest I could get to work was 4.5mm 45deg, it went off on it`s own at 5mm 45deg 🙂

Down side is it doesn`t tell us why it has changed the toolpath, we could do with it throwing up a "Tool too large" error for this maybe ??

Regards

Rob

[Anonymous]

Increasing tip offset gradually diminishes the overlap, at 1 mm value tool paths are separated from each other and gap grows if I increase tip offset value from there.

[Anonymous]

The thing is the cut itself doesn't overlap and is actually nowhere near overlapping, and the way Fusion changes the tool path is the opposite direction of actually making it better?

But anyway, I'll just do it in two ops doing diagonal pairs.

[Anonymous]

Your original file displayed on left, tip offset changed to 1 mm shown on the right, I see nothing wrong with running all 4, close above the part to confirm at first.