I have a design drawn mostly with splines in a sketch (not imported from SVG/DXF or similar.).
The splines have only very few points, and should in theory create smooth radiuses?
When I simulate the toolpath, it has facets along the radius. When cutting the part, these are both visible and can be felt when inspecting the part.
Why is it doing this?
2D toolpaths and splines perform very poorly together, unfortunately. You essentially have two options;
1) Redraw the sketch with actual arcs, which isn't too laborious, but annoying
2) Use 3D Contour with Smoothing turned on:
@seth.madore wrote:
2D toolpaths and splines perform very poorly together, unfortunately. You essentially have two options;
@seth.madore Is this still a problem? In the past on convex areas, In Computer offsets would create a lot of short line moves with a corner rounding fillet between each move so arc fitting was bad. If you used In Control offsets it would arc fill well because there was no corner rounding.
I just looked at the toolpath for this job and the corner rounding problem is no longer present and it is arc fitting quite well.
You can see here the distance between arcs is quite large. This might still cause faceting because the 2 tolerances added together might cause a corner between the 2 radii. Might get better results with a tighter tolerance like 0.0025 and a smoothing tolerance of 0.01mm so the path doesn't wander too much.
Also @johannesJGAKQ What accuracy have you got your simulation set too? I'm not seeing the same faceting you are on the finish cuts with this setting. You still might want to try the 0.0025 tolerance and 0.01 smoothing to see if it's any better.
Mark Hughes
Owner, Hughes Tooling
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@johannesJGAKQ Although this toolpath looks like it has a lot of points, only the roughing passes are made from short moves.
If you turn of the roughing passes and inspect just the finish pass it looks quite good. This is with the finer tolerance.
Mark Hughes
Owner, Hughes Tooling
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I made a quick test sketch just to compare 2D vs 3D, and it seems like smoothing can be equally enabled to both.
Used the Circle tool, the Line tool, and the Spline tool to create radial features. This is using the default tolerance settings.
So with smoothing OFF, I conclude that 3D Contour actually is worse, since it adds points/facets to the circle-arcs and line-arcs as well, whereas 2D contour only does that to the spline.
With smoothing ON, they are essentially the same.
Hi @HughesTooling ,
I dont see a big difference in changing the tolerance. Have tried both 0.0025 and 0.1 (smoothing always set to 0.1 in both cases), and the toolpath appears to be relatively identical.
In either case, this should perform much better with smoothing on, than in my original attempt with no smoothing.
@johannesJGAKQ It does look like they've improved 2d contour and it does quite a good job fitting arcs now. Have you got and constant contouring features on your control that might help with the intersections?
@seth.madore I notice chamfer is still doing the corner rounding so generates lots of short line moves with arcs between each. Can you create a ticket to look at improving this as well?
With a chamfer mill 2d contour does a bit better job but still a lot of short moves on convex areas.
This is chamfer with smoothing enabled.
And this with 2d contour and a chamfer cutter and smoothing. Bit odd fitting works well on some convex areas and not others.
Thanks Mark
Mark Hughes
Owner, Hughes Tooling
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@johannesJGAKQ wrote:
So with smoothing OFF, I conclude that 3D Contour actually is worse, since it adds points/facets to the circle-arcs and line-arcs as well, whereas 2D contour only does that to the spline.
Yes, 2d contour does not need smoothing if your part is made from just lines and arcs, it will create arcs from arcs as you've found.
Mark
Mark Hughes
Owner, Hughes Tooling
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@HughesTooling wrote:Have you got any constant contouring features on your control that might help with the intersections?
I think the closest I have are these settings for path accuracy:
https://demo.buildbotics.com/#settings:general
Is that what you were thinking of?
Fusion
