Dome from Panels

[Anonymous]

I am trying to design panels that will be cut from steel sheets, roller bent, and welded to make a hemisphere (roughly). 

I have more-or-less designed the panel (I need to review it and confirm), but am having trouble verifying my design by building it into a dome. I am looking for help on my next steps, or how to draft my dome such that I can generate a flat panel design to generate the cut pattern for the sheet metal.

I have tried the sheetmetal tools, creating a flange from my panel design and then bending it with the radius (bend override) that I want. This seems to change the shape of the panel and when I pattern it in a circle to make a dome, they overlap. I suppose my panel design could be wrong but I am pretty sure the flange command changes the shape of the panel. Maybe because it flanges between two edges and cuts away everything in between. When I view my sheet metal design flat, the panel shape is clearly altered. It also seems to double my dome radius (and therefore double the needed panels) but that should be a tweakable fix. 

I suppose this is probably doable with sculpting? Although I do not know where I would start with that as I am not a strong sculptor (advice appreciated here if this seems like the easiest solution).

The panel was designed by splitting the Dome cross section into courses, and determining the radius at each course. I suppose another approach would be to draw and arc, and rectangles along the path at the arc along the defined courses of different radii, and loft between each rectangle.... I dunno. 

Thanks for any help! Jeff

[TheCADWhisperer]

Are you OK with a tessellated single curvature solution (doable)

or

are you after a double curvature solution (requires additional steps using MeshMixer and will involve some tweaks for bend allowance tolerances)?

BTW - you might want to investigate Autodesk Inventor Beta http://beta.autodesk.com if you need a double curvature solution.

[Anonymous]

My goal in single curvature, as that makes it much easier to manufacture as well as draw!

[TrippyLighting · Accepted solution]

Loom through the timeline in the attached model and see if you can make sense of it.

It feels like there should be a more efficient workflow, but it did not reveal itself to me.

[Anonymous]

Wow. Thanks

I guess the Sheetmetal 'unfold' was what I was looking for. That is where I was failing from the projection based design approaches. 

I don't really understand sketch 3 or sketch 4. What are their purposes? (Sketch 4 is just to trim the top of the panel off?)

Either way, thanks for your help. I am going to run through it with my dimensions and hopefully recreate!

Jeff

[TheCADWhisperer · Accepted solution]

Hybrid technique does not require Unfold/Refold.

[TrippyLighting]

That is indeed more elegant than my cut/hack/slash approach.

[Anonymous]

Is that because we can use the Flat pattern? What is the difference between unfold and flat pattern?

[etfrench]

How do you create the flat pattern in order to make each section?  The flat pattern command creates a rectangle when the bottom of the panel is selected.

[TheCADWhisperer]

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@Anonymous wrote:

Is that because we can use the Flat pattern? What is the difference between unfold and flat pattern? 

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Hmmm, I know very clearly in my mind, but for some reason that is a tough one for me to answer in words.

Unfold/Refold is often needed during the modeling process to add cuts in proper location relative to their position when the part is folded.

The Flat Pattern is the finished form needed for manufacture.

A feature added to the Flat Pattern would not show up in the folded part.

I don't think I explained that very well.

Maybe somebody else has a better explanation this morning.

[TheCADWhisperer]

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@etfrench wrote:

How do you create the flat pattern in order to make each section?  

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Can you create a Screencast recording or File>Export and then Attach your *.f3d file here where you are having difficulty creating the Flat Pattern?

[chrisplyler]

Unfold/Refold are timeline actions.

Flat Pattern creates a separate entity in the Browser which can be exported as a DXF file.

[etfrench]

That's odd.  Yesterday, the flat pattern just created a rectangle.  Today it's creating the proper shape.

[TheCADWhisperer]

I saw something funny happen yesterday too, but didn't take the time to track it down.

When I saw your response - I thought, uh-oh I should have taken the time to resolve the issue that I saw.

But then when I checked the file - all worked as expected.  

I would make a couple of changes to my design technique now that I have taken a second look at it, but the OP seems to be happy.

[Anonymous]

I stepped away from this project for a bit, and am back at it and stuck again:

I am working on an oven (not a steel umbrella), and trying to create an opening so that when I manufacture the panels, I can cut them from the sheet to spec rather than cutting the opening after. So I will have 7 identical panels, and 3 with cutouts on the bottom.

When I try and intersect two sheet metal parts (the tunnel opening), or just do a cut out (11.34 radius semi-circle) it affect the panels as a pattern, not as individuals. I have seen posts for breaking patterns on sketchs by deleting the glyph, but I cannot figure out how to do it on patterned components. I have tried in the part as well as the assembly.

If no one has a good solution I will just copy and paste all the panels, as I think that will solve it.

Thanks

pre cutcut affects all panels because they are part of the pattern

[Anonymous]

Thanks for your help everyone. 

It worked well...

[Anonymous]

 see here for solution:

https://forums.autodesk.com/t5/fusion-360-design-validate/intersection-with-sheet-metal/td-p/9001855

[etfrench]

That looks nice.  Can you make me one?

[Anonymous]

Still only 1/4 of the way finished. Not the cheapest solution
either....hahah

[Anonymous]

My OP was jun 3rd, 2018. Just fired it for the first time yesterday so....... sure. It'll be ready in a few years!