How to deburr selected edges only?

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Giulio Buccini
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Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

How to deburr selected edges only?

Post by Giulio Buccini »

Hi to all,

what if I need to deburr only specific edges of my object?

The deburr operation seems to work if

- I select exactly one edge;
- I select a closed path.

However, if I select a sequence of edges and then I click on the deburr-op, the command doesn't work.

For example, I tried to select two edges of a simple cube, but the command fails:
Selection_7643.jpg
Selection_7643.jpg (33.32 KiB) Viewed 2304 times
Any clue? :(
Attachments
deleteme-deburr-test.FCStd
(16.4 KiB) Downloaded 28 times
chrisb
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Re: How to deburr selected edges only?

Post by chrisb »

Did you use the latest 0.20?
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Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How to deburr selected edges only?

Post by Giulio Buccini »

Yes. One of the latest build.

OS: Ubuntu 16.04.7 LTS (XFCE/xfce)
Word size of FreeCAD: 64-bit
Version: 0.20.26375 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 8a6e3d1)
Hash: 8a6e3d1b766a34546806b22d750929c2d00e30a6
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: English/United States (en_US)
chrisb
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Re: How to deburr selected edges only?

Post by chrisb »

Use a BoundaryDressup:
Attachments
deburrTwo.FCStd
(12.53 KiB) Downloaded 27 times
SnipScreenshot-5423f3.png
SnipScreenshot-5423f3.png (12.11 KiB) Viewed 2211 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How to deburr selected edges only?

Post by Giulio Buccini »

Uh!
That is a real PITA when the path has multiple "interruptions"... one has to create multiple bounding-boxes... Also my object is rotated around the Z-axis and I have to search for exact coords over any edge to be avoided.

:( :( :(

Another approach to deburring:
there is no way to "draw" your own arbitrary path around a solid by using 2D geometries? (Even if some manual refinement of the gcode would be necessary later?)
bmsaus4ax
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Location: Bargara, Queensland, Australia UTC+10

Re: How to deburr selected edges only?

Post by bmsaus4ax »

Giulio Buccini wrote: Fri Nov 26, 2021 1:27 pm Hi to all,

what if I need to deburr only specific edges of my object?

The deburr operation seems to work if

- I select exactly one edge;
- I select a closed path.

However, if I select a sequence of edges and then I click on the deburr-op, the command doesn't work.

Any clue? :(
This is my experience also.

But an odd thing is this only seems to be a problem when the adjacent edges are straight edges (lines).
If I select a chain of edges that have straight edges connected to arcs there is not a problem until I introduce two consecutive straight edges (lines).

I need to read the Thread for Deburr (original creation thread) from the beginning to get a better idea of the operation as there seem to be a few odd things going on.
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How to deburr selected edges only?

Post by Giulio Buccini »

I have to test this strange behaviour...

Anyway, it is quite strange that, despite offering amazing features, Freecad does not offers the simplest ones.
chrisb
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Re: How to deburr selected edges only?

Post by chrisb »

In case it helps finding th cause of this behaviour: engraving works well on a set of single edges.
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bmsaus4ax
Posts: 255
Joined: Sat Nov 14, 2020 9:16 pm
Location: Bargara, Queensland, Australia UTC+10

Re: How to deburr selected edges only?

Post by bmsaus4ax »

Hi ,
Further to the apparent issue I tried an extremely small and unrealistic fillet between two adjoining edges to check if the de-burr failure might be a precision issue.

A 0.001mm fillet will actually process correctly, but a square edge will not.
( I could only select the fillet with "Finish Selecting Loop" and the deleting edges not joined by a radius.)

In the attached file the path with the fillet produces a correct result.
The path with square edge fails catastrophically, it processes the inside of the two edges and then the outside of the second one.

.
OS: Ubuntu 20.04.3 LTS (ubuntu:GNOME/ubuntu)
Word size of FreeCAD: 64-bit
Version: 0.20.26479 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 00e0fc7)
Hash: 00e0fc73d950a26d9cc41bbc861a53bda7754d58
Python version: 3.9.7
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.3
Locale: English/Australia (en_AU)
Attachments
Deburr_bug.FCStd
(18.18 KiB) Downloaded 20 times
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How to deburr selected edges only?

Post by Giulio Buccini »

chrisb wrote: Sat Nov 27, 2021 6:45 am In case it helps finding th cause of this behaviour: engraving works well on a set of single edges.
I was thinking about that. But I have to calculate an outline, i.e. a distance from the edges to be deburred.
How I could achieve that?

I was thinking to get a 2D-outline of my object by using the Draft-WB.
Here the supposed workflow:

1. switch to DraftWB
2. set top view
3. select the object and then apply "Shape 2D view"
4. transform the shape to a sketch by using "Draft to Sketch"
5. edit the sketch and erase all internal segments, so that only the outline remains
6. transform back the sketch to a 2D shape
7. produce an offset outline of the obtained shape, so that the offset is equal to the asked/required distance of the Chamfer/V-bit tool from the edges
8. Switch to the Path workbench and use the offset-ted 2D-shape as path for an engrave operation
10. Eventually change/adjust the height of the 2D-shape on the Z-axis to get a proper deburr.

Sounds reasonable?
How I get an offset from the 2D-shape at point 7 ???
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