p1mrx @ p1mrx @sh.itjust.works

See also https://lemmy.world/u/p1mrx

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2 yr. ago

I think you could improve the latch design by making it curved, with a large-diameter circle centered on the hinge. But I tried to sketch this in FreeCAD, and my circles are coming out as jaggy polygons instead of round. How do people get anything done with this software?

I suggest changing your cover photo to include a large power tool, instead of a tiny USB cable.

who is life

nice 45° angles.

I suggest uploading some default-size STLs so we can view the parts in 3D.

The difference is, Elon Musk sometimes thinks that it would be pretty neat if his private jets were electric. When has Taylor Swift ever done that??

I haven't done any tests where the tensile/breaking strength is relevant, just rigidity. Maybe it's possible to optimize the infill based on finite element analysis or something, but that's not a rabbit hole I'm looking to go down.

I have tested that an all-walls sandwich (PrusaSlicer "solid infill every 3 layers") does not improve rigidity. So far nothing beats 1-wall + rectilinear in that department.

Okay, but if my 2-wall hook bends into a straight line, then I don't really care about the durability of that no-longer-hook-shaped object.

Edit: I agree that 2-wall could make sense, if your goal is to reuse the hook (with a more appropriate load) after the heavy load falls off. That's analogous to protecting a wire with a circuit breaker.

It's not really clear what you're saying, because they're both "my design". Could you specify 1 wall vs. 2 wall?

I just tested this hook by hanging a 5 gallon bucket and gradually adding water. PLA 1 wall = 1710 g, 2 wall = 1178 g. The thing is, a 1.5 mm hook fails by straightening rather than snapping, so rigidity is more important than strength.

Edit: I also tried PETG: 1 wall = 1441 g, 2wall <998 g (failed to hold the empty bucket)

So the 1 wall hooks can support >40% more weight before straightening enough that the bucket slips off. That's more significant that I expected.

Edit2: Part of that 40% difference is due to friction; the 1-wall hook has a rough surface that makes the bucket less likely to slip off. But even with bluetack on the hooks, 1-wall has less deflection than 2-wall for the same weight.

Another confounding variable is the weight of the hook itself: 2-wall = (0.83g slicer, 0.78g actual); 1-wall = (0.95g slicer, 0.88g actual). I don't know if that extra weight is coming from density or volume, but either way the stronger hook is more expensive.

Sigh, reality is so complicated.

Lock some calipers (with a rod sticking out) to 1.5mm shorter than the part height, compress it down onto a kitchen scale until the rod is just touching the platform, and record the weight.

That's just the first procedure that came to mind. I will try to think of a way to do a hook strength test today.

I've literally never had this happen with a toilet made this century, but if you're buying one it doesn't hurt to check the MaP rating.

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What exactly are your modifiers modifying?

Edit: oh, I see. A modifier lets you draw shapes onto the model instead of cutting planes only. That does seem like an easier approach.

So you're saying it's technically a pirate ship?

You can see in the photo that the wall is just above the waterline. It stays in that orientation until you disturb it enough to spill water over the edge, at which point it capsizes.

It's not rocket surgery. Boats need more weight at the bottom than the top. If you put it in water and it leans, shift some weight in the other direction.

PrusaSlicer has a 'center of gravity' indicator that removes at least some of the guesswork.

The technique can be applied to other models: Use PrusaSlicer's 'cut' feature to break the model into parts, and tweak the settings (mainly infill and perimeters) to give each part the desired density.