Issue with round surface using contour 3D

[Prometeuszu]

Hello i have problem with machining.

When i make countour with ball end mill i get angular surfaces instead of round ones.

Each surface is made by mutliple passes on 1 angle and after 3mm it is making me next angle ;/

I made this surface in fusion so it is arc. 

I changed tolerances but it gives me nothing.

I checked posts from people with same problems but nobody had explanation for this.

[seth.madore]

Would you be able to share your Fusion file here?
File > Export > Save to local folder, return to thread and attach the .f3d/.f3z file in your reply.

[Prometeuszu]

Thank you for reply.

In file there is 1 setup.

I have problem with Contour19.

[seth.madore]

What's the material and what is your machine?

[HughesTooling · Accepted solution]

You might find Smoothing is causing or adding to the problem. The arc fitting will only be added at the end of each level and the arc fitting adds to the tolerance error. So rather than a tolerance of 0.01 you're getting 0.02.

Personally I'd use a parallel cut cutting at 90° to what you're getting using 3d profile. I'd also create a helper surface and extend both end so I could cut past the end of the part.

Something like this. 

This image also hints at meshing might be a problem on an arc this size. You might want to try using Compare and Edit to adjust the triangulation tolerance. Try changing it to tolerance*0.1

[Prometeuszu]

"This image also hints at meshing might be a problem on an arc this size. You might want to try using Compare and Edit to adjust the triangulation tolerance. Try changing it to tolerance*0.1"

Thank you a lot for this. I put 0.005 and i see that surface finish almoust same like from NX. 

Now i understand that fusion is not generating paths from solid but its making triangles 😕

I cant find where i can set it 0.005 as default. You know if need to modify it every time? 

[seth.madore]

No. Once you've changed it to the value you want, click off that field and then right click on it, there should be an option to "Save as User Default"

And yes, most of the HSM toolpaths are calculated against an STL model. The new Flow and Blend toolpath do not, those work against the model itself.

[HughesTooling]

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@seth.madore wrote:

And yes, most of the HSM toolpaths are calculated against an STL model. The new Flow and Blend toolpath do not, those work against the model itself.

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@seth.madore Just tried Flow today on a conical surface (created by chamfering a hole) and was quite disappointed I got no arc fitting because of wander on the Z axis. I would have thought if it's working off the surface U and V it should have produced paths parallel to the XY plane? Edit added test file

[seth.madore]

Hmm, yeah, I would have expected better code. It's possible that I may have misunderstood something, so I'll try to get clarification on what I've stated..

[oleg.tikhomirov]

@HughesTooling @seth.madore I've created a ticket for investiating issue with not working filtering (because of deviations in z) in Flow. CAM-48462

Flow (Preview) makes main calcuation on model directly but triangulated surface is still used and it causes issue. It might be solved now by significant reducing "Surface Triangulation Tolerance". It should not be necessary.

[seth.madore]

Thanks @oleg.tikhomirov!

[HughesTooling]

@oleg.tikhomirov I haven't had time to update Fusion yet but thought I'd attach a test file that shows the problem. With the version I have the triangulation tolerance didn't help.

I also tried Blend but got this! Seems very odd in the corners.

Thanks Mark

[programming2C78B]

I've also been getting a lot of this Z wobble in surfaces, including Spherical. I now have to just use ramp to do something as simple as a port feature/countersink. It doesn't make sense to me.