Freecad Idomatic Method for Radial Cylindrical Cutouts

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justacec
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Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by justacec »

I was looking though some sample parts to model and I ran across the following:
Screen Shot 2021-08-01 at 8.58.46 AM.png
Screen Shot 2021-08-01 at 8.58.46 AM.png (755.21 KiB) Viewed 1540 times
Can somebody tell me what the Freecad method is to get the middle cutouts done correctly.

So far I have modeled two half circles and subtracted those and then have a full wedge to cutout the middle of each cutout region. I know this is poor, incorrect, and inefficient. Looking for tips to do it right.

Here is what I have so far:
Screen Shot 2021-08-01 at 9.05.12 AM.png
Screen Shot 2021-08-01 at 9.05.12 AM.png (79.19 KiB) Viewed 1540 times
Thanks for any feedback.
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Willem
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Willem »

A sketch and a groove works fine here
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papyblaise
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by papyblaise »

I'm not sure you got it right, because it's the edges of the holes that should be 90 °, not the axes
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Roland
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Roland »

How about this solution?

Greetz

Roland
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chrisb
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by chrisb »

Roland wrote: Sun Aug 01, 2021 6:19 pm How about this solution?
It's the same as Willem's solution made with Part workbench.
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TheMarkster
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by TheMarkster »

I think this is correct.

Top view sketch for Pad:
Snip macro screenshot-e83617.png
Snip macro screenshot-e83617.png (120.63 KiB) Viewed 1385 times
Profile sketch to cut out holes from sides:
Snip macro screenshot-bfbf2e.png
Snip macro screenshot-bfbf2e.png (69.46 KiB) Viewed 1385 times
The front view seems to matchup:
Snip macro screenshot-d084b2.png
Snip macro screenshot-d084b2.png (64.79 KiB) Viewed 1385 times
Make 2 subtractive sweeps, one each along the edges in the path sketch, and then use a polar array with 3 elements.
Snip macro screenshot-a1c634.png
Snip macro screenshot-a1c634.png (109.17 KiB) Viewed 1385 times
Could be there are better or more efficient ways to do it.
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Roland
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Roland »

chrisb wrote: Sun Aug 01, 2021 8:25 pm
Roland wrote: Sun Aug 01, 2021 6:19 pm How about this solution?
It's the same as Willem's solution made with Part workbench.
Ah, thanks Willem and Chris.

I did not know the Groove tool. See it working here.

Greetz

Roland
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Roland
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Roland »

TheMarkster wrote: Sun Aug 01, 2021 9:22 pm Could be there are better or more efficient ways to do it.
Markster, I think that your solution is wrong because what should have been a circular cylindrical surface is actually an elliptical cyclinder. This is because you sweep a circle along an angled direction.

Best regards,

Roland
Last edited by Roland on Sun Aug 01, 2021 10:34 pm, edited 1 time in total.
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Shalmeneser
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Shalmeneser »

If someone can do without the Datum plane ...
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Roland
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Re: Freecad Idomatic Method for Radial Cylindrical Cutouts

Post by Roland »

Willem wrote: Sun Aug 01, 2021 2:31 pm A sketch and a groove works fine here
Hi Willem,

How do you place your circle sketch at the correct angle?
Screenshot from 2021-08-02 00-15-30.png
Screenshot from 2021-08-02 00-15-30.png (9.58 KiB) Viewed 1340 times
Those figures for x, y, z and angle seem quite hard to conceive.

Apart from that riddle, I am afraid that your solution is wrong, because the square sketch that you use for grooving intersects with the origin (0,0,0). It is the cylinder's walls that intersect the origin at one specific place.

Best regards,

Roland
Last edited by Roland on Sun Aug 01, 2021 10:58 pm, edited 1 time in total.
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