Floating slices in a cylinder.

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Benji
Posts: 6
Joined: Mon Feb 18, 2019 3:15 pm

Floating slices in a cylinder.

Postby Benji » Mon Feb 18, 2019 3:21 pm

Hello everyone,

Started using FreeCAD today and loving it so far however I can't seem to figure out how to do this one thing.
I created a cylinder with an inner diameter of 41 mm and I want to put 10 slices with a diameter of 40 mm and a thickness of 0.5 mm inside while at the same time being spaced out 9.75 mm from the each other and 4.875 mm from the end of the cylinder.
I can find out how to fill the whole cylinder with another cylinder with diameter 40 mm but how to add air between the slices is something I can't seem to figure out. Could anyone point me in the right direction? Thanks in advance.
target.FCStd
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Bance
Posts: 203
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Floating slices in a cylinder.

Postby Bance » Mon Feb 18, 2019 5:09 pm

You are using PD WB you may only have contiguous single solids in a body, You need to create another body for each of the internal discs, Or swap to part WB create your disc and then create a draft array.

HTH Steve
chrisb
Posts: 14483
Joined: Tue Mar 17, 2015 9:14 am

Re: Floating slices in a cylinder.

Postby chrisb » Mon Feb 18, 2019 5:12 pm

Hi Benji, welcome to the forum.

Besides that, I don't understand your model with adding the top cube and then taking it away in several steps.
Benji
Posts: 6
Joined: Mon Feb 18, 2019 3:15 pm

Re: Floating slices in a cylinder.

Postby Benji » Tue Feb 19, 2019 8:47 am

The top cub was used to have a point to start from for the hole I am making in the side of the cube. This way I started at the right height.
chrisb
Posts: 14483
Joined: Tue Mar 17, 2015 9:14 am

Re: Floating slices in a cylinder.

Postby chrisb » Tue Feb 19, 2019 11:47 am

I see, that's what we called a helper pad in 0.16. In the current versions you can use much more comfortable DatumPlanes, or in your case it is even simpler, you can attach the sketch to YZ plane and pocket through the wall of your cylinder.

Using this technique even further leads to the following modeling:

- attach sketches if possible to principal planes,
- create the small cylinders from the center of the big cylinder and hollow the big cylinder later,
- that hollowing is done from the origin with an offset of 10 mm through the whole cylinder,
- I have merged Sketch008 and Sketch009 together
- there are further optimizations possible, such as making the inner hole of Sketch006 separately and omit sketch holeside and its pocket,
- it would make the model even more robust, if Sketch008 was attached to YZ plane with a calculated offset of Pad003, and the same for Sketch010 with an offset of length of Pad004.

BTW, size of the file has shrunk to only the half.
Attachments
target_cb.FCStd
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Benji
Posts: 6
Joined: Mon Feb 18, 2019 3:15 pm

Re: Floating slices in a cylinder.

Postby Benji » Tue Feb 19, 2019 12:04 pm

Very nice!
Thank you. Guess I have to read up on the new options.