6 ms·

Conical Slicing: A different angle of 3D printing

120 points by fanf2 3y ago

hcrean 3y 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.
- newaccount74 3y 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 3y ago
    Or even alternate to create a weave.
    - WillAdams 3y ago
      Or just do 100% infill and bake in salt and re-melt to get a solid part? https://hackaday.com/2020/09/23/reforming-3d-prints-with-salt-and-heat/ https://hackaday.com/2020/09/23/reforming-3d-prints-with-sal...
  - deleted 3y ago
    [deleted]
  - gerdesj 3y 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 https://www.thingiverse.com/thing:2187167 (2) https://www.thingiverse.com/thing:3553160 https://www.thingiverse.com/thing:3553160
    - mft_ 3y ago
      With respect, I think you're missing the point. No-one doubts that one can print objects which are strong, but it depends on being able to orient the layer lines such that the directions of relative strength and weakness are appropriate for the use case. This is a well-recognised weakness (no pun intended) of 3D printing, even with well-engineered and -set-up printers. In the case of the hinges you linked to, if you were to set yourself the challenge of printing them standing upright on one thin edge, with the hinge barrel running horizontally, the layers would run parallel to the barrel and ultimately run vertically when attached to a standard door. This would make it likely that the hinges would break much more easily once the weight of a door was applied. Happily, this orientation would be crazy, and the obvious orientation (with the large flat areas flat on the print bed) is a strong one.
      - naasking 3y ago
        > but it depends on being able to orient the layer lines such that the directions of relative strength and weakness are appropriate for the use case. I think this is sometimes a bit overblown though. CNC kitchen also demonstrated that you can achieve nearly 80% of the horizontal strength in the vertical direction, you just have to print HOT and SLOW. So "strength" profiles just have to be different than "fast printing" profiles.
        newaccount74 3y ago
        I tried to figure out where that figure was from, and spent about an hour or two watching CNC Kitchen videos on Youtube. What a ridiculously inefficient way of sharing test results! I guess Youtube makes it easy to monetize your work, but as someone interested in results, this is rather frustrating.
        naasking 3y ago
        Pretty sure it was this one, describing the properties of the "transparent glass" printing method: https://www.cnckitchen.com/blog/transparent-fdm-3d-prints-are-clearly-stronger https://www.cnckitchen.com/blog/transparent-fdm-3d-prints-ar... So higher than normal flow, high temp, slow feed rate, and very little cooling showed remarkable strength along layer lines, up to 93% of horizontally printed specimens.
  - zbrozek 3y 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_22 3y 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 3y 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_22 3y ago
  I think the problem is developing the algorithms. At least that's what I got from the article. Its still very hacky.
- kiba 3y 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 3y 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 3y 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.
- zbrozek 3y ago
  These days I bet Klipper doesn't care about how many axes are simultaneously moving.
- causality0 3y 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 3y 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 https://github.com/FormerLurker/ArcWelderLib
    - jepler 3y ago
      arc support may exist but be poor. For example, I recently read prusa's documentation, which states "[G2 and G3 controlled arc move] commands don't propperly work with MBL enabled. The compensation only happens at the end of the move, so avoid long arcs." MBL is mesh bed leveling, an important technology that helps compensate for imperfections in the flatness of the print surface.
      - double0jimb0 3y ago
AaronFriel 3y 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.
_yb2s 3y 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.
- dotnet00 3y 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.
- kragen 3y ago
  stl would be fine for that
yarg 3y 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 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_ 3y 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!
- kragen 3y 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 3y 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 3y ago
  Cnc kitchen did some tests on brick layers: https://www.cnckitchen.com/blog/brick-layers-make-3d-prints-stronger https://www.cnckitchen.com/blog/brick-layers-make-3d-prints-... He saw some strength gains, though not huge gains.
Aspos 3y ago
The author's YouTube channel is worth mentioning, btw.
jayyhu 3y 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 https://www.youtube.com/watch?v=1i-1TEdByZY
splittydev 3y ago
The fact that the carousel doesn't stop on hover makes for a super frustrating reading/viewing experience.
- pimlottc 3y ago
  It’s also oddly slow to react when you tap on another thumbnail
Animats 3y 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 https://www.youtube.com/watch?v=st4MqJZobCM
regularfry 3y 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 https://e3d-online.com/products/revo-belt-nozzles It's originally designed for belt printers but the extra clearance works here too.

120 points by fanf2 3y 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.

newaccount74 3y 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 3y ago
  Or even alternate to create a weave.
  - WillAdams 3y ago
    Or just do 100% infill and bake in salt and re-melt to get a solid part? https://hackaday.com/2020/09/23/reforming-3d-prints-with-salt-and-heat/ https://hackaday.com/2020/09/23/reforming-3d-prints-with-sal...
- deleted 3y ago
  [deleted]
- gerdesj 3y 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 https://www.thingiverse.com/thing:2187167 (2) https://www.thingiverse.com/thing:3553160 https://www.thingiverse.com/thing:3553160
  - mft_ 3y ago
    With respect, I think you're missing the point. No-one doubts that one can print objects which are strong, but it depends on being able to orient the layer lines such that the directions of relative strength and weakness are appropriate for the use case. This is a well-recognised weakness (no pun intended) of 3D printing, even with well-engineered and -set-up printers. In the case of the hinges you linked to, if you were to set yourself the challenge of printing them standing upright on one thin edge, with the hinge barrel running horizontally, the layers would run parallel to the barrel and ultimately run vertically when attached to a standard door. This would make it likely that the hinges would break much more easily once the weight of a door was applied. Happily, this orientation would be crazy, and the obvious orientation (with the large flat areas flat on the print bed) is a strong one.
    - naasking 3y ago
      > but it depends on being able to orient the layer lines such that the directions of relative strength and weakness are appropriate for the use case. I think this is sometimes a bit overblown though. CNC kitchen also demonstrated that you can achieve nearly 80% of the horizontal strength in the vertical direction, you just have to print HOT and SLOW. So "strength" profiles just have to be different than "fast printing" profiles.
      - newaccount74 3y ago
        I tried to figure out where that figure was from, and spent about an hour or two watching CNC Kitchen videos on Youtube. What a ridiculously inefficient way of sharing test results! I guess Youtube makes it easy to monetize your work, but as someone interested in results, this is rather frustrating.
        naasking 3y ago
        Pretty sure it was this one, describing the properties of the "transparent glass" printing method: https://www.cnckitchen.com/blog/transparent-fdm-3d-prints-are-clearly-stronger https://www.cnckitchen.com/blog/transparent-fdm-3d-prints-ar... So higher than normal flow, high temp, slow feed rate, and very little cooling showed remarkable strength along layer lines, up to 93% of horizontally printed specimens.
- zbrozek 3y 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_22 3y 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 3y 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_22 3y ago
I think the problem is developing the algorithms. At least that's what I got from the article. Its still very hacky.
kiba 3y 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 3y 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 3y 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.

zbrozek 3y ago
These days I bet Klipper doesn't care about how many axes are simultaneously moving.
causality0 3y 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 3y 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 https://github.com/FormerLurker/ArcWelderLib
  - jepler 3y ago
    arc support may exist but be poor. For example, I recently read prusa's documentation, which states "[G2 and G3 controlled arc move] commands don't propperly work with MBL enabled. The compensation only happens at the end of the move, so avoid long arcs." MBL is mesh bed leveling, an important technology that helps compensate for imperfections in the flatness of the print surface.
    - double0jimb0 3y ago

AaronFriel 3y 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.

_yb2s 3y 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.

dotnet00 3y 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.
kragen 3y ago
stl would be fine for that

yarg 3y 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 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_ 3y 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!
kragen 3y 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 3y 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 3y ago
Cnc kitchen did some tests on brick layers: https://www.cnckitchen.com/blog/brick-layers-make-3d-prints-stronger https://www.cnckitchen.com/blog/brick-layers-make-3d-prints-... He saw some strength gains, though not huge gains.

Aspos 3y ago

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

jayyhu 3y 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 https://www.youtube.com/watch?v=1i-1TEdByZY

splittydev 3y ago

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

pimlottc 3y ago
It’s also oddly slow to react when you tap on another thumbnail

Animats 3y 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 https://www.youtube.com/watch?v=st4MqJZobCM

regularfry 3y 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 https://e3d-online.com/products/revo-belt-nozzles It's originally designed for belt printers but the extra clearance works here too.