How I mill a concave zone?

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Russ4262
Posts: 941
Joined: Sat Jun 30, 2018 3:22 pm
Location: Oklahoma
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Re: How I mill a concave zone?

Post by Russ4262 »

Giulio Buccini wrote: Fri May 13, 2022 10:35 pm ...
So the 3D surface is a no-go option for me.

So it seems that Path does not offer any chance to "enter" into the material from the side... :( :( :(
Morning Sir.
I kindly disagree. This is a situation where we must think "outside the box." If FreeCAD's selection options do not allow us to interpret the geometry as we want, then we give it the geometry it needs for a correct interpretation - we add helper geometry. There are various ways to do this. I did the easiest for me, modifying the original part, though I could have made a copy, and then modified the copy.
Steps I used:
  1. Activate the Body by double clicking it in the Object Tree. This will also automatically open the Part Design WB.
  2. Select, then pad one of the lateral sides to just over the tool diameter ( I only used 8mm, but I think you desire about 13 mm based on your tool.)
  3. Select the new lateral face created by the pad, and create a sketch on that face.
  4. Use the sketch to trim the face down (think pocket) to the necessary geometry for your Path Job requirements.
  5. Create a pocket out of this sketch to perform the trim, using the same value as the pad ( I only used 8mm, but I think you desire about 13 mm based on your tool.)
  6. Repeat this process of padding and pocketing on the other lateral face of your Body object.
Screenshots and source file attached.

I also added a Profile op in the source file to demonstrate that it is still possible to profile the original Body shape without the new helper geometry.

Have a blessed day, and enjoy FreeCAD.
Russell

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.28793 (Git)
Build type: Release
Branch: master
Hash: 72e91dbbca9094d9bd56b1d47a1eeaaeb7266849
Python 3.8.6+, Qt 5.15.2, Coin 4.0.1, OCC 7.5.0
Locale: English/United States (en_US)
Installed mods: 
  * FC_SU
  * Z_MacroStartup
Attachments
mill_test - Copy.FCStd
Source file
(114.36 KiB) Downloaded 15 times
helper geometry view 1
helper geometry view 1
Snip macro screenshot-242942.png (149.71 KiB) Viewed 528 times
helper geometry view 2
helper geometry view 2
Snip macro screenshot-b88e16.png (107.34 KiB) Viewed 528 times
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How I mill a concave zone?

Post by Giulio Buccini »

Hi Russel,

your is an interessant workaround.

Lately I was thinking on how to creat an helper geometry that can be selected in the geometry list of the 3D-surface tool by pressing the button "Add"... with no success.

I have also tried to create a cloned copy of my object, positioning it next my original one to extend the semicircled surface. Unfortunately, Freecad consider the surface as separated and applies the operation on each one:
Selection_7820.jpg
Selection_7820.jpg (37.98 KiB) Viewed 513 times
Your idea is absolutely not elegant and quite raw, but it seems to me as the only option available. I see no other choices at the moment.
Russ4262
Posts: 941
Joined: Sat Jun 30, 2018 3:22 pm
Location: Oklahoma
Contact:

Re: How I mill a concave zone?

Post by Russ4262 »

Giulio Buccini wrote: Sat May 14, 2022 2:12 pm ... I see no other choices at the moment.
Evening.
I have been piddling with many projects the past few months, some involving FreeCAD. If you are able to build a Git branch from source, perhaps you would like to test a branch I have with some modifications to 3D Pocket. I have added the Extensions feature to 3D Pocket, and also updated the Extensions feature to work with some non-planar extensions, such as what you have need of. The work is experimental and not heavily tested, but I think it could help you out.

Screenshot attached of the modified 3D Pocket and upgraded Extensions feature in use on your model.
Branch is at https://github.com/russ4262/freecad/tree/master_prs and has some other mild mods and fixes. You are welcome to build and use.

Thanks,
Russell

Code: Select all

OS: Windows 10 Version 2009
Word size of FreeCAD: 64-bit
Version: 0.20.29077 +12 (Git)
Build type: Release
Branch: master_prs
Hash: 1a44ffa4963971757a53a626748a94908d25930e
Python 3.8.6+, Qt 5.15.2, Coin 4.0.1, Vtk 8.2.0, OCC 7.5.0
Locale: English/United States (en_US)
Installed mods: 
  * FC_SU
  * Z_MacroStartup
Attachments
Snip macro screenshot-6379bd.png
Snip macro screenshot-6379bd.png (154.99 KiB) Viewed 404 times
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: How I mill a concave zone?

Post by Giulio Buccini »

Hello Russel,

that kind of "extension" option is exactly what I was looking for! :o

Unfortunately at the moment I have not time for testing at all. My life is getting a little bit "complicated" because of the recent increase of prices in Europe, and I'm focused elsewhere... :(
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