Fusion 360 CAM question

Always in over my head…

Could someone please tell me why Fusion throws these curlicues in on the last trip round the pocket? And, how to get rid of them?
It’s a roughing path so I can clean em up later, just like to know why this happens.

3D adaptive toolpath, 1/4” Carbide 3D coated single flute

I have a vague feeling they are related to tolerances. Try increasing your tolerances 2x or 4x and see if that cleans it up. I remember John Saunders mentioning it on a video once involving rest machining.

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Yep, thanks.

Bumped Tolerance in Passes from 0.1 to 0.001, bye bye curlicues!

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The yellow ones are just noncutting movements - they won’t actually hurt anything, it’s just limiting engagement. If it’s a roughing path, seek is always faster than cut (unless you’re in butter, I guess ) You want higher tolerance on a roughing pass, not lower. You’ve basically told it to make the roughing pass within .001 of final.

I was thinking, watching the cut, that it was scalloping the side wall. I guess maybe not? It just seemed, to this wannabe machinist, to be unnecessary moves?

Yeah, Fusion will do that and it seems odd. Also, I meant to clarify, I meant increasing the numerical value of your tolerance, which I suppose means to decrease your tolerances. Language is confusing at times. What I meant was to try changing it from 0.1 to 0.2 and see if it goes away. That’s typically how I do it and those weird scalloping movements go away.

I think that’s what @mikep is also saying.

Ok got it, that makes sense.

There is soooo much I don’t know about CAM.

I like this write up:


Interesting read, thanks.

As a result, I messed with tolerances and smoothing on the path I asked about in the original question. It’s amazing how that affects lines of code, just changing tolerance from 0.1 to 0.2 cut some 25000 lines of code.

Yep, it’s kinda crazy. Also, make sure you use smoothing enabled. It makes nice arcs out of tiny linear segments. That will reduce file size greatly and you won’t notice a difference.

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You guys have my admiration being able to run those programs.
Ive had my shapeoko for a couple of years and i cant figure out how to do many things on it…

Well hell Aaron, you gotta try man. My motto is Fail Your Way To Success!

Thanks for the compliment BTW.

Post any questions, a lot of smart people here to help out.

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Might be…but you also said it was a roughing pass…

Thanks man. Just give it a try and ask questions here and I’d love to help. Parametric modeling programs are fun and just make sense to me, compared to a lot of other programs out there.