HewlettHackard

joined 2 years ago
[–] HewlettHackard@lemmy.ca 2 points 1 month ago

Interestingly, the supports could even dissolve in the main liquid ingredient of the original resin, like a cube of ice in water. This means that the material used to print structural supports could be continuously recycled: Once a printed structure’s supporting material dissolves, that mixture can be blended directly back into fresh resin and used to print the next set of parts — along with their dissolvable supports.

Unless I’m reading this too optimistically, it seems like recovering the resin just requires adding more of the original solvent, which sounds pretty good (as long as that solvent isn’t much nastier than a regular resin solvent).

[–] HewlettHackard@lemmy.ca 2 points 4 months ago

My quick and dirty math based on some captions of the figures from the paper suggest it’s unlikely they’re getting amplification for now, because it seems like the even the “low” resistance state is quite resistive. But I still suspect it can be done, and they do characterize their structures as “active” - thanks!

[–] HewlettHackard@lemmy.ca 2 points 4 months ago (2 children)

Well, a logic gate doesn’t fundamentally have to amplify… if the control current exceeds the output, it isn’t amplifying but fill performs logic. I am too lazy to look myself, but did they demonstrate amplification? If not, I think it’s doable.

[–] HewlettHackard@lemmy.ca 2 points 4 months ago (5 children)

Couldn’t you build an amplifier by using a thin wire that heats up a larger wire? If you size the large wire to minimize self heating, then a small current would cause the thin wire to act as a heater, switching the large current.

[–] HewlettHackard@lemmy.ca 3 points 6 months ago

For what it’s worth, it’s the same with Prusa. The only work I do on my printer is glue stick on the PEI sheet when printing otherwise-incompatible materials.

[–] HewlettHackard@lemmy.ca 1 points 6 months ago

Well said. It’s just important that when recommending printer models to newcomers that we’re honest about time vs money and printer vs printing.

[–] HewlettHackard@lemmy.ca 3 points 6 months ago (5 children)

In practice, I haven’t found the print volume of my MK4 to be too limiting. Occasionally more X/Y would be nice, but plenty of parts that are too big for my printer would be too big for any printer and still need to be cut. The other issue is that even fast 3d printers are slow and I don’t really print things that take entire days. Even printing dactyl keyboard halves takes hours thanks to the need for supports, so I can’t imagine someone frequently doing really huge prints (particularly in height).

[–] HewlettHackard@lemmy.ca 1 points 7 months ago* (last edited 6 months ago)

I had the same experience the one time I tried it. It seemed like it might be trying to do a “ramming” sequence like used on the XL, but it just jammed my extruder. I haven’t tried it again. If you have the time and motivation, it’d be great to submit a bug report to Prusa.

[–] HewlettHackard@lemmy.ca 2 points 7 months ago (1 children)

Interesting, it took me a while looking at your images to figure out why the original design didn’t work. The problem was that there was no solution that could avoid at least one extremely long bridge, and that bridge also forced the adjacent bridges to be “wrong” (though maybe if it printed the super long bridges first, it could’ve made the rest short).

I don’t have much to add besides being surprised the problem was more interesting than it first seemed…and I don’t accept that you were being an idiot because it want immediately obvious to me either. Or I am one too :)

[–] HewlettHackard@lemmy.ca 1 points 7 months ago (1 children)

especially if it were printed vertically, i.e. you would be pulling the final product into your extruder in such a way that it would be pulling against the layer lines.

I agree that vertically-printed filament would have poor tensile strength, but isn’t most of the load from the extruder going to be compression, shoving it from the extruded gear to the melt zone and nozzle? Other than during retractions, doesn’t the tensile stress just comes from pulling the filament off the spool?

 

It occurred to me that one way to potentially eliminate all filament swap waste from purge towers or Bambu-style filament “poops” is to instead do something similar to a “purge object” or a “wipe object” but where the object is… filament.

The idea was somewhat inspired by Stefan’s video from a few months ago, which first introduced me to the idea of printing filament: https://m.youtube.com/watch?v=CQ-N1fr4N0w

If the purge object is new filament, then you don’t need to figure out what to use it for immediately; you can store the mixed-color filament for later use until you have a genuine need for a color-agnostic or structural object. No more piles of fidget spinners you didn’t really want.

A few other thoughts:

  • The filament probably needs a minimum bend radius so it can feed into an extruder without breaking. One option would be to print a circle or a rounded square / squircle type of shape toward the perimeter of the build volume (potentially multiple concentric ones, or spiralized shapes). Another option would be to print disconnected straight segments.
  • The filament doesn’t need to be printed flat. It could potentially spiral upwards (likely with supports). That could help avoid print head collisions for taller models (in which case you might not want the head to have to get back down to <1.75mm from the print bed). In the most general case, the filament could be printed at arbitrary angles, even vertically, and could start at some height above the build plate (potentially supported by the object itself, for example in an object where color changes don’t start at the very bottom). Maybe the angle could even be optimized to provide the best match between purge volume per layer and volume of new filament printed on each layer.
  • A good solution probably requires a good way to connect multiple segments of printed filament together
  • Mixing materials rather than just colors seems like a bad idea to me (e.g. soluble supports) but I’m going to mention it as a possibility anyway; you could conceive of something inspired by Stefan’s composite material and intelligently organize the different materials within your new filament.
  • You could potentially control the mixes / transition colors that go into your purge filament, or even choose multiple different new filaments for different color transitions. For example, you might have separate new filaments for red-green, green-blue, and blue-red transitions. Maybe you want it create particularly pretty new filament, or avoid particularly ugly combinations.

I don’t actually have a multi-color / multi-filament printer, and I don’t have time to experiment with this (even though the first prototype could be as trivial using a filament shape as the wipe object in PrusaSlicer). I’m mostly sharing this to establish prior art in case someone nefarious seeks to patent something similar in the future (which is also why I added some half-baked thoughts that might make other things become obvious to someone skilled in the art), though it’d be great if the idea is actually good and someone could implement it well. Or for all I know this does already exist.

Thanks for taking the time to read this! Feel free to repost/share/steal the idea if you like it.

[–] HewlettHackard@lemmy.ca 14 points 7 months ago (2 children)

What about printing it in two halves the each have a flat bottom? Since the optical quality doesn’t matter, the line down the middle of the lens won’t matter.

[–] HewlettHackard@lemmy.ca 8 points 8 months ago

I think the Jerusalem Declaration on Antisemitism is much better, and allows for legitimate discourse on apartheid, genocide, et cetera. I actually learned about it on Lemmy!

https://jerusalemdeclaration.org/

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