SheetMetal workbench for plastic boxes

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mcdanlj
Posts: 45
Joined: Sun Dec 01, 2019 12:10 am

SheetMetal workbench for plastic boxes

Post by mcdanlj »

I finally played with SheetMetal workbench, and I realized that it might also be a platform for parsimonious modelling of plastic as well as metal boxes.

When I design plastic boxes to print, I sometimes want rounded corners for comfort and/or aesthetics, and adding fillets is finicky selecting all the edges. We're often advised to add them all at the end because they will break and you'll just have to do them over again. But SheetMetal Bends look pretty nice...

I found that setting min gap, offset, and radius to 0, rotating a corner, and then mirroring the rotation twice gave me a beautiful box. So far, not that much different work from from sketch, extrude, plane, sketch, pocket, fillet.
Screenshot from 2021-12-07 19-39-56.png
Screenshot from 2021-12-07 19-39-56.png (26.92 KiB) Viewed 4163 times
However, if I choose the axis of rotation properly for the edges, the angle of the Bend lets me set a draft angle. For example, here it is with a 2° draft angle:
Screenshot from 2021-12-07 18-47-17.png
Screenshot from 2021-12-07 18-47-17.png (11.37 KiB) Viewed 4163 times
This way I end up with a complete box, which can be printed but also is appropriate to mold from the same design, with a very simple (I think) design tree driven only by a single rectangle sketch.
box.FCStd
(69.8 KiB) Downloaded 89 times


The nice thing is that this still applies for more complicated boxes, even ones which can't actually unfold as sheet metal, like this:
Screenshot from 2021-12-07 19-42-47.png
Screenshot from 2021-12-07 19-42-47.png (13.47 KiB) Viewed 4163 times

This preserves all the necessary draft angles so that it could still be molded. Closing the bottom of an inside corner takes a bit of work, but nothing too bad; just a couple of pad-to-face (or to a datum plane).
box-inset-corner.FCStd
(225.54 KiB) Downloaded 75 times
Is this one of those known techniques that I just now stumbled on?
chrisb
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Re: SheetMetal workbench for plastic boxes

Post by chrisb »

Thanks for sharing. Interesting way to get the corners.
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mcdanlj
Posts: 45
Joined: Sun Dec 01, 2019 12:10 am

Re: SheetMetal workbench for plastic boxes

Post by mcdanlj »

I'm so glad I posted this. It meant that I had documented it for myself and this morning when I wanted to design some watercolor trays for a family member, it was easy to remember... Here's a set of full, half, and quarter pan watercolor trays. These are sized for the inside because a watercolor pan is defined as 20x30mm, and I made these 1.5mm thick both to be strong and to have a little weight. But it just needed three size changes and one parameter change from outside to inside dimension.
WatercolorTray.FCStd
(167.11 KiB) Downloaded 39 times
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Kunda1
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Re: SheetMetal workbench for plastic boxes

Post by Kunda1 »

Did (and if not, would) you x-post this to the official sheetmetal forum thread?
It may be worth documenting for the official sheetmetal workbench...?
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