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Missing Extrusion


samc99us
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Posted · Missing Extrusion

All,

 

  Little background and introduction...I've been FDM printing for close to a decade...original Makerbot user, Ultimaker 2, the list goes on including access to a Fusion3 F400 and an industrial SLS machine. Current home printer is an Ender3, but I'm working on a Voron 2.4 for long term large format FDM printing. I've used several of the major slicer programs-MakerWare, S3D and Cura from the 2.x days up to my current install of 4.5. I haven't updated to 4.6.1 due to the flow issue with the Ender 3 and this release. Some basic notes on my Ender3; it has a MicroSwiss hotend and all metal extruder+hardened steel worm gear, along with glass bed, Creality silent board with tuned stepper outputs (Vref) and Marline 2.0.5 bugfix.

 

Generally I get high quality prints. My usual material is Atomic Filaments Carbon Fiber PETG. This particular part is kicking my butt however; I can print it cleanly all day long on the Fusion3 F400 with S3D, but no such luck on the Ender3+Cura. The issue is the missing filament in the walls. I'm attaching two prints and these are the setting changes between prints:

 

1) Print one, lowest number of missing filament sections:

A) Print speed of 30 mm/s, wall speed 25 mm/s

B) Flow rate set to 93% (calibrated for Voron parts is 92% fyi)

C) Print temp 255 C

D) Layer height of 0.24mm

E) 0.6mm nozzle

F) Walls are 1.8mm thick, so 3 walls, 5 layers top and bottom.

G) 100% infill, line infill. This is a hollow part and I want the walls to be continuous.

 

2) Print two, which came out like crap:

A) Print speed of 20 mm/s including walls, tuned down to 16 mm/s during print

B) Flow rate set to 105%

C) Print temp 260 C

D) Layer height of 0.26mm

The rest of the settings are the same.

 

Before you say wet filament, this was dried for 18hrs before these prints.

 

A few notes: The problem clearly happens during a reverse move by the printer. Its like the extruder can't keep up. I'm actually thinking of decreasing the acceleration, maybe that would help, but IMO Cura shouldn't even be reversing, each of these walls should be continuous. Further, it is laying down 4x lines in the walls, not just 3, which is puzzling.

 

And before you say wet filament, this was dried for 18hrs before these prints. I've also seen the same issue on other thin walled parts with different rolls of filament. Solid objects print cleanly all day.

2020-07-04 17.41.53.jpg

2020-07-04 17.42.01.jpg

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    Posted · Missing Extrusion

    I made a couple of tweaks:

     

    1 - set min wall flow to 50% to stop inner walls being printed on top of each other.

     

    2 - set inner wall width to 0.5 to stop the inner wall dropping out where the overall wall thickness is less than 1.5mm.

     

    This now takes around 17.5 hours to print which is 3 hours faster than the original project.

     

    Hope this helps.

     

     

    CE3_133318400_Mountv2.3mf

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    Posted · Missing Extrusion

    Thanks burtoggle, I'll give that a go next.

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    Posted · Missing Extrusion

    Actually, I think it will do better if you turn off combing completely and increase the min wall flow to 80 or thereabouts.

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    Posted · Missing Extrusion

    Hi,

     

    This was a great learning example.

     

    Thanks

     

    Torgeir

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    Posted · Missing Extrusion

    Copy that, I'll give that a go. I think I'll do this next one in standard PETG as a test.

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    Posted · Missing Extrusion

    What is the thought on speeding up the print and increasing layer height? Ideally I'd like to go to 30 mm/s print speed and 0.26-0.3mm layer height with the 0.6mm nozzle but I'm hesitant to do that at the moment. I also have a 0.8mm nozzle on order and will re-build the part with 1.6mm wall thickness to make it a two layer print.

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    Posted · Missing Extrusion

    One other question, how did you determine the z-seam location in this  example? Its not readily apparent, and there doesn't seem to be an easy way to grab the coordinate within Cura.

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    Posted · Missing Extrusion

    Why not, this is a good way to save printing time, -but now you are in experimental mode!

    It all depend very much of the heat transfer capacity of the hot end your printer is using.

    Saying so, I know nothing about your printer for sure.

    Your model shape should fit well in using 0.6 mm nozzle, I'll think.

    I would test with a smaller model with same type of shaping angles hole etc. as your original, -but can be used as a test object to tune up the parameters -with max print time say 45 min.

     

    (It is a good help in using Cura in playback mode to have an overview of the printing path.

    In your above example, the center of the wall line was printed 2 times, I.E. this line was kind of doubled or become to high.

    By studying the path of one complete layer, you could see this very well, I've never seen this before.

    So seeing your print was an eyeopener to me..)

     

    Well, just a thought.

     

    Good luck.

     

    Torgeir

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    Posted · Missing Extrusion

    Hi Torgeir,

     

      I'm kind of using the print that is on the bed at the moment as a test. Upped the speed to 30 mm/s at the moment and it looks pretty good.

     

    A scaled down example would be useful.

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    Posted (edited) · Missing Extrusion

    That's great..

     

    You can specify in the menu "Shell" where/how you can "locate" the Z seam.

    Just put Z in the "search setting" then Shell pop up.

    Hmm. By using sharpest edge, the seam is less visible at this place in your nice curved object. 🙂

     

    Torgeir

    Edited by Torgeir
    Text added.
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    Posted (edited) · Missing Extrusion

    Torgeir,

     

      Yes, I get where that is entered in the Cura settings. What I'm asking is how to find that coordinate in the model...I could probably try relative and pull the coordinate out of CAD, but I'm hopeful there is an easier way within Cura. Google searching came up empty handed so maybe not.

     

     

    Edited by samc99us
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    Posted (edited) · Missing Extrusion

    Hi samc99us,

     

    Sure there is, just open your gcode (the actual one, that's saved to be printed) file in Cura (here Cura 4.6.1). Cura will open the model in sliced mode, so you can only view it manually or replay it. The later versions of Cura will open with selected filament color and shows colored lines or different colored lines if there is some width that's use several lines. Inner wall, infill, outer wall etc.

    Suppose you use gray PLA, then your model will appear gray if you drag down the layer number slider bar on the right side.

    If you then pres start replay, the start point where it start printing will be the layer shift point.

    In multi layer walls it is not easy to see the seam, as this is more a problem for single wall print and here it will be very easy to see the seam. Cura may start with any of the lines in a multi line wall, but at the same point. In your model there's two sharp angels Cura might use, but the one I've used here is on the right side.

     

    So, here is a picture of the whole issue, using Cura 4.6.1:

    (This actual picture here, also show the selector panel for the various "layer type lines" with colors used.)

     

    Layer_Startpoint_232_Infill_Centerline.thumb.jpg.c91edc0dbee155e2b31f3d1b726b8ca4.jpg

    Here you can see the start point of layer 232 -just where the green line start!

     

    If you want to find it in the gcode file, use this tool:

     

    http://gcode.ws/

     

    (I'm using this one quite often.)

     

    I'll hope this clarify the issue.

     

    Regards

     

    Torgeir

     

     

     

    Edited by Torgeir
    Additional reference.
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    Posted · Missing Extrusion

    Torgeir,

     

      Nope, I totally get that, its basically the same view as the Preview menu....that start location was defined by burtoogle, but how did he determine the correct coordinates in the first place. Again, even in your view, no coordinate is given unless you count the lines on the print bed or some other way. Google was not help.

     

    The good news is these new settings are working very well!!

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    Posted · Missing Extrusion

    Hi samc99us,

     

    Understood, I'll think the best one to answer this one is @burtoogle for sure.

     

    Regards

    Torgeir

     

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    Posted · Missing Extrusion

    Hi samc99us,

     

    Maybe this tread help then?

     

    https://github.com/Ultimaker/Cura/issues/5510

     

    Torgeir

     

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    Posted · Missing Extrusion

    Nope. Haven't found a single thread pointing to how to find model coordinates in Cura.

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    Posted (edited) · Missing Extrusion

    Hi samc99us,

     

    Took some time to make some better explanation of this coordinate use in the Z seam setting in Cura.

     

    The first mode is Z seam relative coordinate setting.

     

    Here's a picture of your print in Cura 4.6.1

     

    1122312547_Curacoordinat_S_Z_Rel.thumb.jpg.bf30ff91bc099a13d79d624b8ee35f49.jpg

    Hopefully this is self explained!

    IMO. This is the closest you can go using mm to find position like this in Cura.

     

    Next picture is showing the situation when Z seam relative is deselected.

     

    666128417_Curacoordinat_S_Z_Not_Rel.thumb.jpg.1f4b9f5254e6042f2539517e0be76ca5.jpg

     

     

    I've learned a few thing, by your question and I hope you find some use of it!

     

    Regards

     

    Torgeir

     

     

    Edited by Torgeir
    Error in Picture corrected.
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    Posted · Missing Extrusion

    Hi samc99us,

     

    I've just revised my previous posting Z seam relative/absolute coordinate setting.

     

    Thanks.

     

    Torgeir

     

     

     

     

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    Posted (edited) · Missing Extrusion

    Thanks Torgeir, I think the best way is to do relative and pull the coordinates out of Solidworks. IMO Cura should implement a way to grab a model coordinates when hovering over the model with your cursor. The other way this is done is by just looking at the model dimensions in the lower left and cutting them in half with the relative option checked to put the seam on an edge.

    Edited by samc99us
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