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iccherry

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  1. Interesting. I'm using Cura 4.3.0 on an UM3E. As I mentioned, the speeds are different, but my accelerations for both fine and fast profiles are the lower values.
  2. The only difference I can find in the newest Cura fast (0.2) and normal (0.1) profiles is the layer height, wall overlap, and the speeds. All the accel, jerk, and other settings look identical to me.
  3. I've had quite a few problems with cylinder walls (have a thread about it) with my UM3E. I never get perfectly smooth results with Cura on them for some reason. Especially small diameter cylinders, like you're looking at.
  4. Cura 4.3.0 with the most current firmware ( 5.2.11.20190503) on the UM3E.
  5. Sorry, misinterpreted what you meant by feeder wheel. 🙂
  6. Can you post the gcode? You might look at the extrusion at those layers, and that can help identify if it's hardware or software that's causing the problem. I'm also having trouble with thin walls. Might be related.
  7. Well. This is just frustrating. Eliminating the outer wall wipe and wall overlap seemed to make an incremental improvement, but there are still extrusion issues. Further, it almost seems like Cura is turning the curve into a rougher polygon than Slic3r. The vertical artifacts from the interpolation of the curve seem much larger in the Cura version. I may just need to open an issue on the Git for this. I am lost for explanations. For reference, on the left is an earlier Cura print. Middle is the Slic3r print. Right is the new Cura print with 0.333 walls, no overlap compensation or wipe. It looks "ok" in the photo, but again, in person, there are a lot of issues. The layers look like some lines are missing in places.
  8. Thank you for the feedback. I didn't post up the photos (just to keep clutter down, and they don't show anything new), but I actually tried a couple things to address those issues. First, I thought, perhaps it's that gap filling and the middle wall causing the issue. So, I reprinted with 0.40 nozzle and default 0.35 line width (stock profile). Then, I set fill small gaps = nowhere, and set infill to concentric, just in case. Result: still the same. The outer wall extrusion gcode still has skips in it, and the print was still rough. The gcode did looks smoother (it was drawing circles), and it wasn't zigzagging in the middle wall, but that didn't matter. Second, I tested the line thickness. I set the 0.8mm nozzle to 1.0mm line width, which is exactly the width of the wall. Result: still stuttering extrusion. Still an ugly print. Gcode still shows the blips in extrusion. But maybe going over the nozzle size has other problems, so.... I have a print going right now with 0.40 nozzle, 0.333 line width, no gap fill, and concentric everything. The gcode still shows the extrusion stuttering, but that should help determine how much line width matters, as it should just require three equal lines to make the 1mm wall. /edit/ It's not quite done, but I can see enough of it to say that the line width didn't make a difference. The finish is still rough, with extrusion irregularity. /edit/ /edit2/ I found an issue listing on the Cura github that discusses what appears to be this, but it's unresolved. https://github.com/Ultimaker/CuraEngine/issues/702 They mention the possibility that it's "outer wall wipe distance" or "wall overlap compensation" causing the problem. I have a model printing with those set to zero/off. I'll have to check it out tonight, but it did look (at a quick glance) like the gcode didn't have the extrusion stuttering. The wall wipe didn't seem to have an impact on the code, but the wall overlap did. It's like the calculation for the required extrusion when compensating for the overlap is a little off or perhaps "mathematically correct" but non-constant, leading to surface irregularity. Hopefully that's it! /edit2/
  9. Ok, I realize I might be talking to myself here, but I think I'm on to what's actually happening. With the 0.8mm lines, Cura is stuttering the extrusion. See the green spots? Those are movements with no extrusion. Here's the gcode for that section. Note the movements with no E values: Now, this introduces fairly visible artifacts in the simulated part. See the vertical lines? Those are the corresponding movements with no extrusion: The Slic3r gcode exhibits nothing but the seam, and that's the only place it has movements without extrusion. Here, you can see how clean the simulated extrusion is. Finally, I checked the other Cura file that I had sliced with 0.40mm lines. Here's what's odd, Cura starts out doing the middle line by tracing the curve... then it switches to trying to do infill with 45 degree lines. And *then* it tries to go back and fill in the gaps. It makes no sense, when it just needs to plot a circular single fill line, but that's what it's doing. Here, you can see the initial infill is a nice smooth curve. Then it starts to zig zag. And here's that same section when it come back and tries to cross hatch/fill it. Needless to say, the 3d model of that pattern is as ugly as the actual print. So.... I have no idea. Cura seems to just slice curves in odd ways. It's not extruding consistently, and it's also inconsistent with how it's handling the infill. Any thoughts?
  10. It's all tradeoffs. If you want something more rigid than PLA, you're going to either have to look at super high end pure thermoplastics (PEEK, PEKK) or fiber reinforcement. People think PLA is low end because it's cheap and easy to print. It's not. PLA is actually one of the strongest, stiffest filaments that is commonly available. The big downside to PLA is that it's not very thermally resistant. It melts at a low temp, and thus can't be used at even moderate temperatures. The only thing stronger that's reasonable is perhaps PC. But it generally won't be quite as stiff. It's pretty strong at higher temps also, but must be thus printed at higher temps. Nylon can be strong af, but it's also pretty soft and flexible. PEEK and PEKK are amazing, but holy crap expensive and you need an actual oven to print them. Here is data from 3dxtech (and this will vary from manufacturer to manufacturer) on their filaments. They have a good selection, and while this won't apply to every manufacturer's filaments, it's a good reference for comparison. All numbers are Mpa. Material Tensile Strength Tensile Modulus (stiffness) Flexural Modulus (stiffness) PLA 56 2865 3185 ABS 42 1950 1985 PC 62 2410 2200 PETG 51 2218 2380 PEEK 100 3720 2700 PEKK 105 3200 2900 PLA (CF) 48 4950 6320 ABS (CF) 46 5210 5260 PC (CF) 70 6200 5890 Nylon (CF) 63 3800 3750 PETG (CF) 56 5230 5740 PEEK (CF) 105 8100 8300 PEKK (CF) 105 8210 8300
  11. Yes, I originally assumed that was the problem also. I have had this problem across many models with various wall thicknesses (almost exclusively using a 0.40mm nozzle). This is an example to show the problem. Honestly, this is just one of the issues I'm seeing (constant extrusion issues seem to be happening, but again, it seems it's Cura, not my machine). Printing with a larger nozzle helps to *show* the problem. It is exaggerating it. It is not causing it. I have just finished printing the same stl with a 0.40mm nozzle and the default 0.35mm line width "fast" profile. So, the wall is approximately 3x the line width. It's harder to see the artifacts this way, especially in a photo on the internet, since the features are half as large, but they are still there. And in person, they aren't difficult to see. Note, the print on the left is the Cura 0.40mm nozzle version. The version on the right is the same one I posted above with 0.80mm nozzle in Prusa Slic3r with the same speeds and temps. Look at the evenness of the lines. The Cura version is quite rough, both inside and outside. There are also some runs in the Cura version layers where there's underextrusion or something. I've been having a lot of problems lately with surface quality, and I'm just trying to figure out how I can do better. I was worried I had a mechanical issue or something, but I figured I'd try a different slicer, just to rule that out, and here is what I'm seeing.
  12. Yes, I'd considered that. However, wouldn't that just get rid of the benefit of using a larger nozzle elsewhere in the model? These cylinders are just simple models to show what I'm seeing in more complicated things. I want to be able to print faster (and I'm willing to sacrifice quality in small details), so I'm using a 0.8mm nozzle. Doesn't narrowing the line width defeat that purpose? I'm not sure if Cura does anything dynamically there, do they? I'm reprinting right now with a 0.40mm nozzle to see if that helps. I'll upload results when it's finished. Also, the same nozzle, speeds, temps, retraction, etc in Prusa Slic3r produces this (attached). The walls of both prints are just a hair over 1mm thick. It's clearly a slicing issue, as the stl, filament, and machine are the same between these two. I'm including the hacked together gcode for the Slic3r version, for reference. 40mm Cylinder.gcode
  13. Sure. I'll use an even simpler model, as these are just examples. Here's a 40mm cylinder with 1mm thick walls. That's it. Designed in Fusion 360 with two circles and two extrusions. I used the default 0.40mm "fast" 0.2mm layer height profile with the following two adjustments: 0.80mm line width (because I'm using a 0.8mm nozzle) and I changed the brim to 2mm. Result: hideous. UM3E_40mm Cylinder.3mf UM3E_40mm Cylinder.gcode
  14. I am constantly struggling with artifacts in my cylinder walls on my UM3. Blobs, zits, random noise. This seems to always happen in the same places if I use the same model to test with, so it's got to be coming via Cura. I have tweaked retractions, coasting, z-hop, speeds... nothing seems to get nice smooth walls. I've cleaned the extruder. Swapped cores. Cleaned and lubricated every rod, and checked for play. Any ideas? I've tried printing down to 45mm/s at 0.2mm layers, and I feel like I was able to get this quality from much worse printers. Here is an illustration. The rough print was sliced by Cura. It's the best one I was able to get after tweaks. The smooth print was sliced with Prusa Slic3r (and then I hacked in the start and end code from the Cura file to get it to work). The Cura slice is full of irregularities. The other is incredibly smooth. Same STL. Same filament. Same layer heights. I believe there is a 5 degree difference in print temp, but that isn't driving the result (I've tried it). I do understand it's difficult to tell with this filament, but I've done the best I can with the photos to show what I'm talking about.
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