Submitted 11 months ago by callcc@lemmy.world to 3dprinting@lemmy.world
https://lemmy.world/pictrs/image/55295609-2d5d-41c4-bde7-8561fc3cfe22.jpeg
Has anyone thought about printing narrower lines in order to get sharper corners? Once Linear advance or Pressure advance is activated, you don’t get bulging corners anymore… but can we do better?
Has this been implemented anywhere yet? Does it have a name?
Isn’t this exactly what Pressure Advance does?
To my understanding, pressure advance only compensates for non-linearities in the extrusion process. These non-linearities, if not taken into account would thin out the path at the beginning (missing pressure) and lead to an excess of material at the end (excess pressure buildup).
With perfect compensation of these non-linearities but no changes to the target line-width and path, the minimum achievable outer radius is equal to that of the extrusion width. I’m wondering if that minimum radius could not be reduced by progressively reducing the target extrusion width the closer you get to the corner. On top of that you would need to adjust the path towards the outside in order to keep the outer wall straight.
Exactly. And the PA tuning that Ellis has is great for tweaking it.
Maybe my sketch doesn’t make it clear. I mean to intentionally make the extrusion narrower and make the print path go outwards to compensate for the narrower extrusion.
Not sure what you mean by printing ‘narrower’ lines. The width of a line is going to be set by your nozzle
You can totally extrude both narrower and wider than your nozzle. Heck, if you have a Slic3r based slicer like PrusaSlicer, Orca, SuperSlicer, etc and your extrusion width is expressed as a percentage, that percentage is a percentage of layer height - NOT nozzle diameter.
If you’re using 0.2mm layers, your extrusion with is expressed as a percentage, and you’re using a 0.4mm nozzle your extrusion with is less than your actual nozel diameter.
I print most of my prints with a 0.4mm nozzle and 0.6mm extrusion width.
This is definitely not true of OrcaSlicer, at least not anymore. I’m running an 0.6mm nozzle and 120% layer width at 0.2mm layer height results in 0.72mm line width, not 0.24mm.
Nonesense. It’s a combination of the amount of material extruded and the layer thickness.
So you would need different later heights around the edges just to stack those ever thinner lines? How do you think this will interact with the rest of the print?
That’s a really lovely illustration
I would keep the layer height constant.
The lines are not circular. You can have narrow lines and wide lines with the same height. The height is controlled by the space between the nozzle and layer below. The width is controlled by the amount of material you extrude.
I get that but your original sketch seemed to be showing smaller and smaller radiuses shaping the edge, which necessarily implies thinner and thinner layers. Now I fail to see what’s different from what sliders currently do.
Interesting. This is new to me and it looks like it could work. It could be usefull if you print with 0.6 nozzle at 0.6 mm width and then in a corner narrow it down to 0.4 mm
Exactly. Cura already does variable width lines but mostly to be able to print narrow sections or to fill narrow space between outlines. It could also use this technique to do sharper corners. Unfortunately to my understanding, firmwares don’t yet support G1s with variable target extrusion rates. Ie. start extrusion rate = X and end extrusion rate = Y. Using this feature, my idea could be implemented in just 5 G1s per corner vs 1 for non-sharp corners.
New Lemmy Post: Sharp corner algorithm (https://lemmy.world/post/9687238)
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Aux@lemmy.world 11 months ago
That looks cool in 2D, but do it in 3D and you’ll see the issue - your corner will be lower than the rest of the wall.
callcc@lemmy.world 11 months ago
Why would that be?
sj_zero 11 months ago
Because the same squeezing effect shown in the 2d plane would occur on the 3d plane as well.
Aux@lemmy.world 11 months ago
Explained it above - lemmy.world/comment/6119616
rambos@lemmy.world 11 months ago
Why lower if you print everything at the same layer height?
Aux@lemmy.world 11 months ago
Filament is not squeezed as a 2D dot, it’s squeezed as a 3D sphere. If you decrease its radius, it will physically decrease in all three dimensions, not just two.
ComradeKhoumrag@infosec.pub 11 months ago
Use cylinders instead of spheres?
Aux@lemmy.world 11 months ago
That will be very complicated.