Designing model locomotive kits using Assembly and other workbenches

Discussion about the development of the Assembly workbench.
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kcleung
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Designing model locomotive kits using Assembly and other workbenches

Post by kcleung »

Say if I were to design a part, which comprises of:

* solids that are made by CNC, 3D printing or casting;
* sheetmetal processed by lasercutting, waterjet cutting or photo etching followed by folding; and
* soldering and/or welding of the above parts together to form the finished part

then an assembly of parts by loose, transitional or interference fit.

For solids, obviously I will start with Parts and PartDesign workbenches.

However, for sheetmetal where I design the needed parts, then place the parts onto a sheet for lasercutting or photoetching to get optimal placements, and to simulate folding of the cut parts before assembly, what are the best tools?

Also, in the case of photoetching, one of the common way to easily get folding right is to half-etch along the line to be folded, if the edge radius is so small that it is close to the thickness of the sheetmetal. Then when the part is folded, it tends to fold along that line.

So what is the best workflow to design such an assembly? If we can do this well, then FreeCAD can be a great tool to design kits for model locomotives :)
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jpg87
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by jpg87 »

kcleung wrote: Tue May 04, 2021 11:09 am...
Uh, a lot of things in your post!
No one has dared to answer yet, so I try.
kcleung wrote: Tue May 04, 2021 11:09 am For solids, obviously I will start with Parts and PartDesign workbenches.
This is as good as I would, with a preference for PartDesign (very personal).
kcleung wrote: Tue May 04, 2021 11:09 amsheetmetal ...
There is Sheetmetal WB, which I have not yet had the opportunity to test.
https://wiki.freecadweb.org/SheetMetal_Workbench

Regarding the assembly WB, there are 3. It is up to you to choose the one that best suits your expectations.
https://wiki.freecadweb.org/A2plus_Workbench
https://wiki.freecadweb.org/Assembly3_Workbench
https://wiki.freecadweb.org/Assembly4_Workbench

Very personal opinion again, I really like working with Assembly 3 WB.
My website : http://help-freecad-jpg87.fr updated 2023/11/06
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bambuko
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by bambuko »

kcleung wrote: Tue May 04, 2021 11:09 am ...
* sheetmetal processed by lasercutting, waterjet cutting or photo etching...
Your design workflow should start by talking to the suppliers (I am assuming you will outsource)
Here an example:
https://www.ppdltd.com/artwork-guide.html

There is a lot more to model photo etch than simply sheetmetal WB in FreeCAD ;)
I am using Link branch and Assembly3
you can also download ... and try it here
excellent Assembly3 tutorials here
kcleung
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by kcleung »

bambuko wrote: Fri May 07, 2021 11:38 am
kcleung wrote: Tue May 04, 2021 11:09 am ...
* sheetmetal processed by lasercutting, waterjet cutting or photo etching...
Your design workflow should start by talking to the suppliers (I am assuming you will outsource)
Here an example:
https://www.ppdltd.com/artwork-guide.html

There is a lot more to model photo etch than simply sheetmetal WB in FreeCAD ;)
ah true...... thanks for your pointer.

So what is the best workbench/workflow for creating assemblies that features photo-etched sheetmetal? Is it still shetmetal workbench? would be nice of sheetmetal workbench if apart from subtraction (cutting through) and folding, it also have etch function where you can specify areas of half edge from each side :)
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bambuko
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by bambuko »

kcleung wrote: Sat Aug 21, 2021 7:29 pm ...would be nice of sheetmetal workbench if apart from subtraction (cutting through) and folding, it also have etch function where you can specify areas of half edge from each side :)
perhaps it would be nice...?
but probably too complicated?
Most of the guys doing it use something like https://qcad.org/en/ to produce vector file formats required by etching people.

I am not using sheetmetal workbench for my project (https://en.wikipedia.org/wiki/KISS_principle),
but would be very interested how you get on - share with us ;) your models and results?
I am using Link branch and Assembly3
you can also download ... and try it here
excellent Assembly3 tutorials here
C_h_o_p_i_n
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by C_h_o_p_i_n »

Hi all,

when I first had a look at FreeCad I also thought that sheet-metal might be good to make brass-etching-templates.
But I think the WB is designated to an other goal in mind.

What would be needed would be an unfolding mechanism which keeps track on corners (bendig grooves) where during etching a lower thickness/etching is needed to facilitate the bending during the assembley of the etched elements ....

https://www.themt.de/mt-0170-etch2-49.html

Also one would need a cut-mechanism to extract the unfolded structures-to-be-exported to dxf/pdf

Regards,
Stefan
kcleung
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Re: Designing model locomotive kits using Assembly and other workbenches

Post by kcleung »

C_h_o_p_i_n wrote: Mon Aug 23, 2021 11:20 am Hi all,

when I first had a look at FreeCad I also thought that sheet-metal might be good to make brass-etching-templates.
But I think the WB is designated to an other goal in mind.

What would be needed would be an unfolding mechanism which keeps track on corners (bendig grooves) where during etching a lower thickness/etching is needed to facilitate the bending during the assembley of the etched elements ....

https://www.themt.de/mt-0170-etch2-49.html

Also one would need a cut-mechanism to extract the unfolded structures-to-be-exported to dxf/pdf

Regards,
Stefan
You are right.... So is the unfolding mechanism and the cut mechanism best implemented in the sheetmetal workbench, or in another possibly new workbench?

And do you know how the design and simulation of the etched sheetmetal done in other CAM software such as Solidworks?

Thx!
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