Conical Slicing: A different angle of 3D printing

https://www.cnckitchen.com/blog/conical-slicing-a-different-angle-of-3d-printing

by fanf2 • 2 years ago

120 54 2 years ago

hcrean• 2 years ago

This is actually kind of an awesome idea, printing overhang has been a issue with printer adoption, and greatly limits some of the parts you can fabricate. I hope this becomes mainstream in the major slicers soon.

newaccount743• 2 years ago

In my experience printing overhangs is rarely an issue.

The big issue that I have is that the orientation of the layers determines the strength of the part. Any vertical tension pulls the layers apart, so sometimes I wish I could somehow print a part in two orientations to make it stronger...

progman32• 2 years ago

Or even alternate to create a weave.

gerdesj• 2 years ago

You can get some surprisingly strong prints. I have a plastic storage unit in my garden (don't judge me).

The doors are about 4'h x 5'w. The hinges broke on the left door a few years ago and I printed some more in PLA from a Thingieverse design (1). They have put up with quite a lot of weather (UK, South West). One did fail but not by layer separation - the hinges sheared diagonally across the layers, ie the "threads" snapped instead of separating. I printed another and a huge lump of plastic carries on being useful instead of land fill.

I generally use a gyroid infill but that is as far as I go off piste from the defaults. Prusa MK3S - self assembled, stock everything. Filament "Sunlu" ie Amazon random and it seems to work well.

If layer printing is an issue for you then you might want a different process or look into inter layer adhesion. I'm no expert on that but I did study Civ Eng at college so I have an idea about shear and moments n that. I generally print small parts where strength isn't an issue. If you need a reasonable challenge to test your gear, try printing a small tank and turret (2) pick one with a long barrel and print it with the barrel vertical.

(1) https://www.thingiverse.com/thing:2187167 (2) https://www.thingiverse.com/thing:3553160

zbrozek2• 2 years ago

There are better and worse plastics for this, though you're right that it is always a consideration. TPU and PET self-adhere extremely well if you need strength in that axis.

engineer_222• 2 years ago

Cnckitchen (original post) has done a lot of research into anisotropies of various plastics and settings, with surprising results. Check out his YouTube for more information

impossiblefork• 2 years ago

I've felt that it's strange that these kinds of things aren't more standard, but I'm guessing it's harder to tune the machines for this?

The core idea is basically the same as that of the Nubian vault, so the core idea is very ancient. One can do this with snow too, to build somewhat surprising structures without having to use supports.

engineer_222• 2 years ago

I think the problem is developing the algorithms. At least that's what I got from the article. Its still very hacky.

kiba• 2 years ago

3D printing as a hobby took off in the late 00s. It's not surprising that there's still fruits to pick, though the low hanging fruits are gone.

jopsen• 2 years ago

While I really like the idea of enabling 3d printers to do more/better through software.

I'll admit that lower complexity might be better.

When prototyping maybe it's better to tweak parts a bit for better 3d printing. And rely on simpler slicing tech.

More software might not make it more reliable, which is probably a bigger problem.

Current limits are annoying, but my 3d printer can still do a LOT I couldn't do before.

AbrahamParangi• 2 years ago

Back in the day I implemented this, the trick is that the firmware motion planner is generally by default not designed to handle smooth curves in 3D, only in 2D. We could have adjusted to fix that but the other issue was it makes the printing/slicing process even more unpredictable, which therefore makes it harder to use as an engineering tool.

zbrozek2• 2 years ago

These days I bet Klipper doesn't care about how many axes are simultaneously moving.

causality03• 2 years ago

If I recall correctly, 3D printers don't even handle smooth curves in 2D. I've heard CNC people express contempt at how primitive the Gcode used by printers is, how it doesn't support any of the advanced features of machine movement that create smooth curves.

tslater2006• 2 years ago

This is correct the last I read about it, but there was a project called ArcWelder that would post-process your gcode and convert the motions to true arcs. The printers today support the arc gcode, but the slicers don't generate them.

https://github.com/FormerLurker/ArcWelderLib

imtringued• 2 years ago

The 3D printer community is oddly resistant to step files. They claim that step files get converted to STL and therefore it doesn't matter. Except there is an obvious problem with this argument. First of all a mesh isn't an STL file, second the printer can adapt its mesh generation based on your slicer settings so that it always has a high enough resolution. Third, the mesh generator can adaptively generate high resolution meshes in complex geometries and low resolution meshes at simple geometries in the same part. Fourth importing step files generates G code with arcs which speeds up printing time.

https://www.reddit.com/r/BambuLab/comments/w15mg6/improvemen...

naasking6• 2 years ago

I've heard CNC people express contempt at how primitive the Gcode used by printers is, how it doesn't support any of the advanced features of machine movement that create smooth curves.

The firmware supports them last I checked, it's the slicers that don't output proper arcs.

naasking6• 2 years ago

We could have adjusted to fix that but the other issue was it makes the printing/slicing process even more unpredictable

Can you elaborate on this? How was the process more unpredictable?

AaronFriel• 2 years ago

Very cool project, breaking the assumption that the nozzle must lay down material while moving on the same plane as the bed is a great innovation.

One nit though about the website: I found it very distracting that the images kept cycling between slides, and by the time I was halfway down the article, I realized that they were cycling even when off-screen.

UniverseHacker• 2 years ago

We need a simple file format and or mathematical expression that describes the 3D clearance around the nozzle for a particular printer. This way slicers can automatically slope things as much as possible automatically. I suspect this would be useful on most printers even without modifying the hardware- even a a very small layer slope would improve overhangs a lot.

dotnet003• 2 years ago

The clearances don't tend to be all that big since most good part cooling ducts surround the nozzle. That said, many higher end hobbyist printers have the ability to physically tilt the bed/gantry, which would allow for true non-planar printing accessible to a large number of people with just appropriate gcode and slicer improvements.

Edit: Actually, come to think of it, it's common for the front to remain open, for easily viewing the nozzle during printing. So non-planar prints should be possible on pretty much any printer in the y axis at least.

kragen2• 2 years ago

stl would be fine for that

yarg• 2 years ago

I was thinking that (if possible) adding a sinusoidal vertical element to the layers (in both the x and y axis), similar to a crinkle crankle wall.

https://en.wikipedia.org/wiki/Crinkle_crankle_wall

There'll be a limit (some point before the head hits the previous layer), but it would still help to mitigate the weakness of planar printing.

_carbyau_• 2 years ago

I like your idea.

And doing it only 2 or 3 layers in height shouldn't be out of reach for most FDM printers while adding significant strength I'd imagine.

But "I'd imagine" and "real world execution" are very different things!

kragen2• 2 years ago

it'll help a lot with shear failures between layers, but only very slightly with tensile failures between layers. and if i'm not mistaken, tensile failures are the bigger problem

crinkle crankle walls are that way to make them strong in flexure, so they don't just fall over when the wind hits them (failing in tension in the mortar joints between the bricks at the base on the windward side). that particular failure mode isn't relevant here because the other layers of the print already protect against that

Doxin• 2 years ago

It'd significantly increase surface area between the layers, wouldn't it? I can only imagine that makes for a lot better layer adhesion.

spott• 2 years ago

Cnc kitchen did some tests on brick layers: https://www.cnckitchen.com/blog/brick-layers-make-3d-prints-...

He saw some strength gains, though not huge gains.

Aspos• 2 years ago

The author's YouTube channel is worth mentioning, btw.

jayyhu• 2 years ago

He also has a video on YouTube for Conical slicing (for those that prefer watching videos): https://www.youtube.com/watch?v=1i-1TEdByZY

splittydev• 2 years ago

The fact that the carousel doesn't stop on hover makes for a super frustrating reading/viewing experience.

pimlottc• 2 years ago

It’s also oddly slow to react when you tap on another thumbnail

Animats• 2 years ago

You need a slicing system that understands breakover angle. That's not unreasonable. There are CAM systems which really understand the boundaries of the tool, cutting head, and machine.[1] The best ones can work in very constrained situations. It's expensive software, because it has to actually work right to avoid expensive damage.

There's a whole frontier here, to build 3D printing systems that have more intelligent path planning than just slicing.

[1] https://www.youtube.com/watch?v=st4MqJZobCM

regularfry• 2 years ago

Since this was written e3d have released a nozzle that's particularly appropriate for this sort of use case: https://e3d-online.com/products/revo-belt-nozzles

It's originally designed for belt printers but the extra clearance works here too.

Conical Slicing: A different angle of 3D printing

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