Sheet Metal Workbench

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Gunt
Posts: 4
Joined: Sun Sep 01, 2019 7:31 pm

Re: Sheet Metal Workbench

Postby Gunt » Sun Sep 01, 2019 8:45 pm

Hi Everyone,

I have been using the sheetmetal-workbench to unfold parts.
It works great most of the time.

Sometimes it does not. Like when the part is not perfectly drawn.
That's why I started thinking about a slower semi-manual way of unfolding.

Imagine....
The user selects one bend (cylindrical face), and then runs an unfold-macro.
The user is asked for a 'k'-value, and then only the selected bend is unfolded, using that k-value.
The user has to repeat this process as many times as there are bends.

I hope for three advantages:
1) If one bend is badly drawn, it would still be possible to unfold the bends that are neatly drawn.
2) The macro would have less analysing to do to detect bends, this might result in a more robust process.
3) It would be possible to unfold different bends with different k-values.

Of course the already available unfolding macro works faster, because it unfolds all the bends at once.
But this semi-manual-macro would be very useful for some special cases.

Sadly, I have never wrote a Python-macro...
Is anyone interested in writing such a macro?


Kind regards,
Gunt

OS: Windows 7
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.18.16093 +38 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.3)
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papyblaise
Posts: 2150
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Location: France

Re: Sheet Metal Workbench

Postby papyblaise » Mon Sep 02, 2019 6:41 am

Hello
You should have written a new thread rather than reopen this dinosaur, many functions of this workshop have evolved.
If you want to unfold arcs with different k, you draw 1 first, unfold it with 1k, continue your drawing on the first unfold by a new arc, use a second k, on this new unfold draw a 3st arc, use a 3st k , etc.
you will have to draw the object separately with all the corresponding arcs with the final unfold, it is a little longer to do
Gunt
Posts: 4
Joined: Sun Sep 01, 2019 7:31 pm

Re: Sheet Metal Workbench

Postby Gunt » Mon Sep 02, 2019 7:17 am

Thanks for your reply, and sorry for opening this dinosaur...

The parts are already fully drawn, I imported them from a step-file.

Kind regards,
Gunt
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Kunda1
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Re: Sheet Metal Workbench

Postby Kunda1 » Mon Sep 02, 2019 4:47 pm

Gunt wrote:
Mon Sep 02, 2019 7:17 am
Thanks for your reply, and sorry for opening this dinosaur...
Hi @Gunt, you actually posted this in the right place (per the sheet metal workbench recommended forum discussion thread) so you're all good. You can also consider next time creating a separate post that references this one and then post on this thread the link to the newly created post.
Also if you need help with macros, feel free to post a request for help in the python scripting and macros sub-forum
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
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papyblaise
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Location: France

Re: Sheet Metal Workbench

Postby papyblaise » Tue Sep 03, 2019 9:43 am

I'm back because I Don't know why you need to change k because in general we change k depending of the thicknes of the sheetmetal , if you have a part in thickness constant , why change k :?:
Please give us an exemple
Gunt
Posts: 4
Joined: Sun Sep 01, 2019 7:31 pm

Re: Sheet Metal Workbench

Postby Gunt » Tue Sep 03, 2019 7:03 pm

Example:
A part with a 'sharp' bend with a bending radius of eg 2mm.
And on the same part another bend with a large radius of eg 200mm.

To produce the correct part, I need to unfold these 2 bends with a different k-value.


To be able to use different k-values for different bends is not the only goal of this new macro-proposal.
But because it would work one bend at a time, one could automatically use different k values if necessary.

Kind regards,
Gunt
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easyw-fc
Posts: 2857
Joined: Thu Jul 09, 2015 9:34 am

Re: Sheet Metal Workbench

Postby easyw-fc » Tue Sep 03, 2019 7:17 pm

Gunt wrote:
Tue Sep 03, 2019 7:03 pm
To produce the correct part, I need to unfold these 2 bends with a different k-value.
you may have a look at this
FreeCAD_SheetMetal:README.md
Particularly at FreeCAD_SheetMetal#material-definition-sheet
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-alex-
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Re: Sheet Metal Workbench

Postby -alex- » Tue Sep 03, 2019 9:52 pm

papyblaise wrote:
Tue Sep 03, 2019 9:43 am
I'm back because I Don't know why you need to change k because in general we change k depending of the thicknes of the sheetmetal
FYI K factor may vary following thickness, bend radius, material, and angle. BTW sometimes it is more convenient to use an exotic value of bend deduction for special bending conditions, hence an unusual k factor (e.g.: flatened bend 180°).

IMHO such a macro which unfold one bend at a time selected manualy could be useful to unfold special parts as Gunt requested (especialy for sub-contracting jobs about not reliable step format models). In this way the user could deal with special k factor or give up wrong bends that can't be unfolded.
However, as Easyw-fc shows the sheet metal workbench is already very convenient for most cases :D
Gunt
Posts: 4
Joined: Sun Sep 01, 2019 7:31 pm

Re: Sheet Metal Workbench

Postby Gunt » Sat Sep 07, 2019 7:44 am

Thanks to easyw-fc for mentioning the "Material Definition Sheet".
And I agree with Alex that the sheet metal workbench is already very convenient for most cases.
I'm certainly thankful!!

Freecad is a stunning example of what can be done by voluntary cooperation.

But of course, for the special cases... a basic macro to just unfold one bend... I keep dreaming:-)

Have a nice weekend!
Gunt
drmacro
Posts: 1149
Joined: Sun Mar 02, 2014 4:35 pm

Sheet Metal Work Bench use case

Postby drmacro » Fri Oct 25, 2019 1:02 pm

I have installed the Sheet Metal WB V0.2.31 in FC 0.19.

I have successfully created some bent examples.

The generic process being: create a thin slab, select an edge or face, bend, model holes/features, unbend(flatten).

In a past life, with a now obscure CAD package, this was one work flow.

Another work flow that was possible was to define a bend line on a surface where I wanted a bend to be made. And bend it there, even possibly adding relief cuts in the corners automagically.

I have not been able to figure out how to define a bend at a specific place on an existing flat object.

Is this possible? (If there are examples of how to accomplish this, I've not found them, please point me to them.)

:?:


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