Nonplanar Printing
tams.informatik.uni-hamburg.de
tams.informatik.uni-hamburg.de
Oh, and if it does get taken upstream, consider publishing the paper along with the code for documentation.
Also very cool that they are releasing their full Slic3r implementation for anyone to use, rather than just publishing a paper.
[1] https://hackaday.com/2016/07/27/3d-printering-non-planar-lay... [2] https://github.com/makertum/non-planar-layer-fdm
Actually I wonder if internal waviness could be a useful method to add strength in general (area should be increased as ~1/cos(angle), or ~(1+angle/29) for very small angles, i.e. about 3% per degree).
The problem that results is the actual dynamics of the extrudate varies a lot, going through a fixed size nozzle: there's a relatively limited range of shapes that do not excessively impede flow (and risk jamming/clinging to nozzle/dragging) and are sufficiently smashed into the previous layer. So if you have layer thickness varying a bunch over an otherwise continuous layer, pretty easy to have poor adhesion in many places or pressure building and later overextrusion.
Also there's a fair bit of lag-- often hundreds of milliseconds- between extruder movement, pressure change, and extrudate geometry changes. When you're moving the nozzle at, say, 100mm/s over the surface, the uncertainty of this lag translates to a big uncertainty of where on the part extrusion thickness changes.
Here is a video of an early print when I was helping him test. He generated the gcode for me based on his machine settings so it wasn't perfect and very rudimentary. https://youtu.be/M3Bwo0AVML0
One potential shortcoming is it looks like their model of nozzle geometry (they need to be able to detect interference) assumes it can be modeled with an angle plus a distance where there's bigger things. But real nozzles are more complicated than that.
The worst thing is that the bottom of the nozzle is flat, and any Z movement downwards is going to smush the just extruded trace.
If you really want conformal layers you need a five axis platform. The flat tip of FDM nozzles is an important part of layer adhesion. I've seen a little bit of experimentation with pointier nozzles and it went very poorly.
Nowadays I'm building the five axis version and packaging it up in a service [1], along with a bunch of other improvements that are only feasible when you stop trying to build a machine lay-people can operate.
[0]: https://github.com/nick-parker/bread [1]: https://www.praxismfg.com/
Can't wait to see more of what you are doing soon.
I should have some fancy demo prints online in a few weeks here, keep an eye on the website!
Is the idea to print planar (xy) support layers, that does have stair stepping, and then to print the final layer by either tilting the bed or by simul-stepping in {x,y} and z?
If so, it seems you'd still have quite a lot of variability in the surface because the underlying support layer is stair-stepped. But that variability would be smoothed due to it being printed continuously at the angular offset from horizontal.
1) In general, you set the number of layers above and below the supports that you want when printing so that the variability of the support layer gets smoothed out. It seems like this should be possible here as well.
2) End products of 3D printing, especially for things like props/costumes, almost always have to be post-processed via sanding, filler epoxy, and/or primer filler paints before they're considered good enough for actual use. This process could make that post-processing step a lot faster.
3) This process is specifically for FDM printers. On an SLA/DLP printer, you would mitigate the stepping issue by lowering your layer height (layers in the example here look quite high - SLA/DLP would probably be 1/10 the height)
or if you moved the head "with the grain" you can move faster when you're on the peak of a step and slower in the valleys.
or maybe if you can place the planar ridges closely enough, you can always go "with the grain" when you are off-plane, always in the valley, and thus improve flatness. of course this requires an axis of rotation or stepping in {x,y} simultaneously.
I'm glad they released the work OSS so it can be incorporated into other slicers and such; I don't have a 3D printer yet, but it's on the drawing board for the future.
Hopefully, though, this will be an option that can be turned off, because sometimes you might want that "stairstep" effect...
The algorithm looks pretty lousy. Even so, it's a big improvement.
With a really good algorithm, I bet you could get much better results (source: I do similar stuff with a 3d pen). I hope this triggers a rush of researchers seeking to one-up each other. This could get super-impressive if it copied what human artists do, or surpass it.
This is one of those things I (and probably a million other people) feel dumb for not having thought of before. It's so obvious in hindsight.
Would this be smoother still if they made 2 passes with the non-planar layer?
arcfitting, motion planning, pressure regulation
https://github.com/Zip-o-mat/Slic3r/commit/9fcd7f38de44ecaa0...
edge detection
then some random other random geometric stuff.
I'm sure its way more complicated than that. Not something you pick up in 10 minutes.