book shelves

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ProfMac
Posts: 4
Joined: Wed May 06, 2020 11:30 pm

book shelves

Postby ProfMac » Thu May 07, 2020 12:15 am

My first FreeCAD project.

This is an update of some bookshelves that I made back in 1985. That was my first woodworking project, and the design was done with a letterpad and a yellow #2 pencil. Some of those parts have disappeared in time, so I changed the design a bit.

The original did not use any fasteners. This design doesn't either. It (should) hold a load, but if you lift a shelf from the bottom it disassembles in your hand. Using the first version, I learned that this is very counter intuitive.

I did a lot, I say a lot, of mouse clicking to put this together. I am sure there are lots of shortcuts available that I don't know yet. Feel free to inspect my work and offer up some tricks of the trade.

When I view this in wire frame mode, I notice a few of the dimensions are a little bit off. They are probably just fine for wood work, but I am going to be prissy about it and tune everything up. To do that, I plan to study the Python interface. So if you have sample Python code to go through an entire application and change a dimension on some part or pad, I'd love to have a link to it. I have successfully used Python to make doc.Box().

I posted a 10 Mb FreeCAD file that you can download. The project only uses about 5 parts, and it would be a good idea to make a smaller file that only has those parts in it. I haven't done that yet.

Oh, I rotated a sketch. Rotations are really hard to do in your head. I also have a Second Life account. Rotations are hard there too, but I have some jigs I have built over the past decade. Also, it is easier to visualize there.
  • [*}Walk the project elements and tune selected parts
    [*}Change all the material specification to wood
    [*}Learn if FreeCAD can do a load analysis
Last edited by ProfMac on Thu May 07, 2020 11:19 am, edited 1 time in total.
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kisolre
Posts: 2102
Joined: Wed Nov 21, 2018 1:13 pm

Re: book shelves

Postby kisolre » Thu May 07, 2020 4:35 am

Hello and welcome to the forum :-)
Your link gives

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Apache/2.4.29 (Ubuntu) Server at amcintosh.vima.austin.tx.us Port 80
You should attach some screenshots here.
ProfMac
Posts: 4
Joined: Wed May 06, 2020 11:30 pm

Re: book shelves

Postby ProfMac » Thu May 07, 2020 3:30 pm

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kisolre
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Re: book shelves

Postby kisolre » Thu May 07, 2020 9:01 pm

Looks nice :)
ProfMac
Posts: 4
Joined: Wed May 06, 2020 11:30 pm

Re: book shelves

Postby ProfMac » Sat May 09, 2020 11:19 am

FEM

I want to simulate some weight on the shelves, and have some idea if they are sturdy enough, before I actually start doing woodwork.

I have run a FEM example, and then created my own simple example. It seems simple enough to run a FEM on a body.

I have tried to fuse two bodies. This results in everything being placed back to a common origin, the spatial relationship of the original bodies is lost. I hoped to take the existing shelves without needing to change the position of many things.

I have tried to make a part with multiple bodies. I haven't learned how to make a mesh from a part.

I have read a bit on Mesh groups, boundaries. I may know enough at this point to understand any help the forum can offer me.

So, please direct me to some interesting FEM threads, or post some simple guidance here.

Thanks

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ProfMac
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Joined: Wed May 06, 2020 11:30 pm

Re: book shelves

Postby ProfMac » Thu May 14, 2020 3:59 pm

I made the footer use some parametric data.
I thought about using mortise & tenon, but this version is using a dowel pin.
I am also letting the entire bottom contact the floor. This will require special installation and be a headache, but will allow heavier loads.

Next up, I want to use the same sketch in these cutouts for the pad in the next part, the "standard."


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bernd
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Location: Zürich, Switzerland

Re: book shelves

Postby bernd » Sat May 16, 2020 6:57 pm

I would just use one shelf and run an analysis on this one piece. Just add an analysis, some material, some fixes, some load, mesh the shelf and press the run button. If you have problems post your file, but clear (not delete) the mesh object first.

bernd