Chamfer/Fillet Issues

[jtwographics]

I've been trying to solve some issues with fillets and chamfers and while I have solved several problems I still have just one issue I can't iron out.

First problem that I solved was reading several posts about how DXF files imported from Illustrator were problematic (despite having used Illustrator & AutoCAD for over a decade and being very precise with my drawings), I redrew the profile as a sketch in Fusion.

Other problems I solved were by coming at the process another way to keep fillets and chamfers on outside corners rather than inside corners. (Most of the errors happened on inside corners)

But this last error has to be from the sketch profile and I just can't figure out what's wrong with it.  I am attaching a screen capture to show specifically which edge is the problem, and the .f3d file for anyone to look at.

Thanks very much for any suggestions/assistance 
Lee

[jtwographics]

I've been trying to solve some issues with fillets and chamfers and while I have solved several problems I still have just one issue I can't iron out.

First problem that I solved was reading several posts about how DXF files imported from Illustrator were problematic (despite having used Illustrator & AutoCAD for over a decade and being very precise with my drawings), I redrew the profile as a sketch in Fusion.

Other problems I solved were by coming at the process another way to keep fillets and chamfers on outside corners rather than inside corners. (Most of the errors happened on inside corners)

But this last error has to be from the sketch profile and I just can't figure out what's wrong with it.  I am attaching a screen capture to show specifically which edge is the problem, and the .f3d file for anyone to look at.

Thanks very much for any suggestions/assistance 
Lee

[jhackney1972 · Accepted solution]

You will always have issues with very tight inside corners when you try and chamfer an edge.  This is due to the chamfer overlap.  This is especially true in the area in my screen capture shown below.  To allow the chamfer to be applied to the complete outside edge, I added some very small fillets to these inside corners, much more to the one marked, to allow the chamfer to succeed.   Model is attached.

[jhackney1972 · Accepted solution]

You will always have issues with very tight inside corners when you try and chamfer an edge.  This is due to the chamfer overlap.  This is especially true in the area in my screen capture shown below.  To allow the chamfer to be applied to the complete outside edge, I added some very small fillets to these inside corners, much more to the one marked, to allow the chamfer to succeed.   Model is attached.

[jtwographics]

John,

Thank you for that suggestion, I will keep it in mind for the future.  However, when I apply the exact same process to my existing file, it doesn't work.

I have been sketching and re-sketching this profile all night last night and all morning today.  I've drawn it with 3 point arcs, control point splines, fit point splines, and finally a tangent arc.  I achieved some success with the control point and fit point splines but the tangent arc solved it the fastest and easiest, which leads me to believe the underlying issue was a tangency problem with the two arcs on either side of the spline point indicated by the green arrow.

I had seen some older threads about problems with profiles coming in via DXF from Illustrator, but after this experience I think that Fusion has far stricter tolerances for tangents between curves.  I am sure that's for accurate machining, but it would be helpful if there was some way to validate the underlying sketch.  Do you know of any tool that would help with this?

Thanks,
Lee

[jtwographics]

John,

Thank you for that suggestion, I will keep it in mind for the future.  However, when I apply the exact same process to my existing file, it doesn't work.

I have been sketching and re-sketching this profile all night last night and all morning today.  I've drawn it with 3 point arcs, control point splines, fit point splines, and finally a tangent arc.  I achieved some success with the control point and fit point splines but the tangent arc solved it the fastest and easiest, which leads me to believe the underlying issue was a tangency problem with the two arcs on either side of the spline point indicated by the green arrow.

I had seen some older threads about problems with profiles coming in via DXF from Illustrator, but after this experience I think that Fusion has far stricter tolerances for tangents between curves.  I am sure that's for accurate machining, but it would be helpful if there was some way to validate the underlying sketch.  Do you know of any tool that would help with this?

Thanks,
Lee

[jtwographics]

Strike that, your procedure did work on my model - I was applying too large a chamfer distance.

[jtwographics]

Strike that, your procedure did work on my model - I was applying too large a chamfer distance.