Bendbox experiment

I’ve grumbled several times about the steep learning curve of Fusion 360, but it keeps drawing me back, like Don Quixote to a windmill. So I present to you the Bendbox (aka the “Box-on-a-Diet”), which represents my stab at learning the sheet metal tools and the colorific plugin for the Glowforge:

I started with a “simple” sketch of the profile of one side. (It was simple in appearance, but fiddling with properly constraining the relationship between curves was fiddly.) Next I swept a surface and used rotated copies as snipping tools to carve the side into its hourglass shape:

The top and bottom tabs were easy enough, but the curved tabs are tricky. Not only do the sides meet there at a non-square angle, but one side curves over the edge of the other:

This is where Fusion 360 really shines… I could make modifications to the sketch and instantly see them reflected in the rendering of the 3D corner as they were propagated forward through the entire construction history. So cool! A quick interference check let me know exactly when I had things adjusted properly. (My Inkscape workflow would have required lots of tricky math or, more likely, a series of prototypes as I honed in on the right values.)

Finally I converted the thickened side into a sheet metal part and generated an unfolded view:

I used the colorific plugin to export an svg and experimented with living hinges in Inkscape. (This is where Fusion 360 comes up short… I was not going to fiddle with cutting profiles with that many cuts, as that part of the system is still very manual.

My first attempt was a hexagonal living hinge (from the Obrary swatches), but it was far too fragile even for my gentler bend radius:

So instead I made a fine mesh of offset dashes for maximum bend-ability. (My prototyping material of choice is Home Depot 1/8" chipboard, not a high-flex material.) Here’s the mesh mid-burn (gotta love that burn ordering algorithm):
Next some alcohol on the tight bends:

And then into the jig (a Fusion 360 quickie that snaps together at top and bottom):

And then assembly:

And that’s about it! No adjustments were necessary, everything fit perfectly just as Fusion 360 showed:
It’s definitely a nice tool to have in the arsenal!


Impressive mix of techniques… but what is it?

A learning experiment… Right there in the title! :wink:


I use SolidWorks and don’t know Fusion well at all. When I have to do patterns, I make a seed and then use the built in pattern tools. Makes it a lot easier to adjust later. This may be what you did also.

When I prep for cutting, I create a new sketch on the surface of the flat part and then use the SW built in “Convert Entities” function. This creates a new sketch on the edges of the existing sketch, including curves, holes, etc. Then I offset that sketch for the kerf adjustment. Then I create a drawing of the part and add a sketch over the second sketch, but this one in the drawing. Then I can hide the base sketch and set my colors to control cut priority. Depending on your complexity the extra time can really be worth while.


Fusion has a whole workflow tab for manufacturing, including profiles accounting for kerf in cutting scenarios. It’s impressive, but not built (yet) for thousands of tiny cuts. No problem for me, I just want it for its 3D smarts!


Wow! Nice corset box! You pulled off some serious curves on those sides! (Rather like @rbtdanforth’s cylinders.) :sunglasses:


Wow, your Quixotic quest is paying off!

I love both your use of the SM tools in Fusion 360 and your use of jigs in assembly.

Like so many things posted here, I don’t have a use for a corset box, but the technics you have shared will stick in the back of my head and be used at some point.



That is really cool! My first Glowforge project was to do something like that only round. It did not work out near as well :cry: I had visions of a box with a colonnade around the outside. Kinda like a Greek temple.


Whoa! Nice work, baby bro!


Wow. Love this. Great curves


Amazing! Kinda looks like an architectural piece on the side of a building to me.

I wonder if one could make living hinges right on the tabs, to make them match the curves and slants better? Probably not, or at least not without plenty of glue.


This is a terrific piece and write up. May be showing my age but looks like Mae West box to me.


With a fine-cut hinge like I used, it might work…


Do it! Do it!


A quick Google search for Mae West box (or corset box, mentioned earlier) was unproductive… Though it’s a stretch to call mine a box when it has no top or bottom in this iteration!

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Mae West was an old time movie star - silent to talkies) and the nick name for a life jacket.


Major kudos! Love your experiment! I get very excited with Fusion possibilities, have zero time to get where I’d like to be.


You could try making various shapes, instead of four sides, try 6 or eight, or an odd number. The more sides you have, the more round it becomes, until you have a column. Experiment with different materials like acrylic and now you have the potential for colored lamps.


Did fusion 360 come up with the stagger logirythem?

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There is also the possibility of soaking or steam bending like so

Though I was not able to get more complex than cylinders :stuck_out_tongue: