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Cura 4.6.1 Flow Rate Problems


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Posted · Cura 4.6.1 Flow Rate Problems

Hey all!

 

I had the same problem with my Ender 3 (Silent board with Merlin 1.1.8 firmware). It's been printing flawless for more than a year until the latest releases of CURA. I  tore down half the 3-D Printer to make sure it wasn't a mechanical issue.

 

My solution to this problem is very simple. Just adjust the flowrate in your start G-code in the machine settings.

 

M221 S(flowrate percent)

 

My start G-code below:

----------------------------------------------------------------------------------------------------

; Ender 3 Custom Start G-code

M221 S95 ;Set flowrate to 95 percent

G28 ; Home all axes

G92 E0 ; Reset Extruder

G1 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed

G1 X2 Y20 Z0.3 F5000.0 ; Move to start position

G1 X2 Y200.0 Z0.3 F1500.0 E15 ; Draw the first line

G1 X2.4 Y200.0 Z0.3 F5000.0 ; Move to side a little

G1 X2.4 Y20 Z0.3 F1500.0 E30 ; Draw the second line

G92 E0 ; Reset Extruder

G1 Z2.0 F3000 ; Move Z Axis up little to prevent scratching of Heat Bed

------------------------------------------------------------------------------------------------------

 

To check that it is working during a print, go into the Ender 3 "Tune" menu and scroll down to flow (The tune menu is only visible while printing). 

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Posted · Cura 4.6.1 Flow Rate Problems

Hey,

 

i had the same issue after Upgraded my creality ender 3 to silent board 1.1.8 and update to Cura 4.61.

Solution from SLY999 works fine for me.

 

after lots of testing i figured out that "Initial Flow Setting" will be also subtracted from previous Flow Settings and its not an absolut Value

 

If i leave Flow at 100 % i got following gcode in first Layer

;TYPE:SKIN
G1 F1200 X105.99 Y105.99 E33.34682 -> this is the Extrusion Value at 100% just as reference

 

Now i set Flow to 95 % and leave "Inital Layer Flow" at 100% 

;TYPE:SKIN
G1 F1200 X105.99 Y105.99 E31.67948 - Extrusion Value is 95% instead of 100 %

 

 

after that i set Flow to 95 % and set "Initial Layer Flow" at 95 % 

;TYPE:SKIN
G1 F1200 X105.99 Y105.99 E30.09551 - now Extrusion Value is 95% - 95 %

 

according to Cura Popup Help text Flow Settings shouldn't be affected by each other, do i misunderstood the Flow Settings or is it a bug?

 

 

 

 

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    • 3 weeks later...
    Posted · Cura 4.6.1 Flow Rate Problems

    Hi could you explain your gcode more like sly999 please I have done slys way added the code at the start and it's verified in tune menu. Happy days. Im just wondering how you change it so there's more flow for first layer like you have and  if that's even needed By the way cheers

    Cheers. 

     

     

     

     

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    • 4 weeks later...
    Posted · Cura 4.6.1 Flow Rate Problems

    I'm also struggling with my Ender 3 pro and Flow rate. However when adapting the value of Flow in the Material section, less material is pushed trough the nozzle, so I do not have this issue on Cura 4.6.1. However I never heard a clicking noise before, and after adjusting this value it appeared on slower printed areas. Does someone know how to fix this?

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    Posted · Cura 4.6.1 Flow Rate Problems

    You should never hear strange noises... If have to find out what produces the noise and find a solution so it stops doing that!

     

    I had a slipping gear on the extruder, that also produces a clicking noise... My extruder tried to push more material through the nozzle than that was possible...

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    Posted · Cura 4.6.1 Flow Rate Problems

    No I have never calibrated the extruder e-steps. I think that that is a good first step to do. However if the printer is indeed over-extruding, then I need to lower the flow I guess, and the clicking will appear again. I printed a cylinder and the clicking appeared on some layers while on others it did not. I also checked the bed and a piece of paper slightly scratched the nozzle.

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    Posted · Cura 4.6.1 Flow Rate Problems

    Want to iterate same issue here on 4.6.1, adjusting the flow has no impact. This can be verified by going into Tune on the Ender during a print as previously stated, you will see no matter what the flow is always 100.

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    Posted · Cura 4.6.1 Flow Rate Problems
    On 8/18/2020 at 8:33 PM, yazooo said:

    Want to iterate same issue here on 4.6.1, adjusting the flow has no impact. This can be verified by going into Tune on the Ender during a print as previously stated, you will see no matter what the flow is always 100.

    That is because the flow on the screen of your printer is based on a change on what is in the g-code. It will always show 100%, regardless of what you change in Cura.

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    Posted · Cura 4.6.1 Flow Rate Problems

    "That is because the flow on the screen of your printer is based on a change on what is in the g-code. It will always show 100%, regardless of what you change in Cura."

     

    The only caveat is if you put an M221 in the Cura "startup g-code" (which doesn't effect Cura computations as start-up gcode isn't a setting).  That M221 directly affects the printer and will change the flow % of each extrusion line in the gcode file and the new flow % will show up in Tune / Flow Percentage on the LCD.  The printer does not display the Cura settings, but Cura uses your flow settings to make it's calculations.

     

    My Ender 3 Pro (silent board with Marlin 1.1.8) only requires that the E-steps be calibrated.  Once that is done, if the gcode says extrude 10mm then exactly 10mm will be extruded.  That is 100% flow.  I found that using calibration cubes and trying to calculate flow by wall width was maddening.  Cura has modifiers to flow, but generally, with a .4 nozzle at .2 layer height you are filling a .08mm² rectangle.  1mm of filament is 2.40mm² and doing a bit of math that comes out to .033mm of filament per 1mm of extrusion.  If you do a careful check of the Enumbers in a Cura generated gcode file (where all flows were at 100%), that's what you will find.  Simplyfy3d uses a fudge factor of 1.2 in it's flow calculations (THAT was hard to find).  Instead of filling a .08mm² rectangle it calculates it at .096mm².  So if the instructions you use for a wall calibration cube were written by someone using Simplyfy3d you will really struggle to hit the numbers and then your prints will be over-extruded.

     

    So the best way to figure out if you are flowing correctly is to do as Mari said and calibrate the E-steps.  After that use your eyeballs to see how the finish looks.  If it looks good then it's good.  If you look down a wall and can just see a faint line between the parallel extrusion stripes, it's good.  If there are ridges and stringiness back and forth on a mesh, you are over-extruding.  If you can see the layer below as a crosshatch pattern you are under-extruding.  If you are manually leveling then the first layer is never a good indicator of flow because the height is dependent on the leveling procedure.  The second layer is better and should look really good except at the ends of runs where the print head slowed down but there was still pressure in the chamber leaving slight ridging (the Coasting setting helps that).  After you get a feel for the machine you can fine tune the flow % of particular areas using the various settings.

     

    Calibrating the steps/mm of all 4 axis needs to be done periodically as the machine will change slightly as it wears in. 

     

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    Posted · Cura 4.6.1 Flow Rate Problems
    23 hours ago, nallath said:

    That is because the flow on the screen of your printer is based on a change on what is in the g-code. It will always show 100%, regardless of what you change in Cura.

     

    If that is the case, then why after making the above change in the g-code does it now show the new flow rate number I set it to?

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    Posted (edited) · Cura 4.6.1 Flow Rate Problems

    To paraphrase Nallath - "That is because the flow on the screen of your printer is based on a (manual) change on what is in the g-code. (Without a manual change like that (or an M221 line added to the Start-up gcode)) It will always show 100%, regardless of what you change in Cura."

    _____________

    For an example - Cura doesn't inform the printer that Print Flow was calculated at 110%, Outer Wall Flow at 95%, and Infill Flow at 50%.  There is no reason to do that since the printer planner only acts on the E values that it actually receives.  The printer doesn't need to know what numbers were used in the calculations that came up with those E values.

    The printer planner always calculates it's own delta E number based on the Global Flow % stored in the printer.  If there is an M221 in the gcode or if you use the LCD and change Tune/Flow (which is an internal M221) then the printer planner uses the new Global Flow % (and displays it) when it calculates the steps/mm required to send to the extruder motor to extrude the correct amount.

    And that is also why the E-steps need to be calibrated.

     

    Edited by GregValiant
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    Posted · Cura 4.6.1 Flow Rate Problems

    I created an account to post this, but in Cura  4.6.1 (the only one I have tested) the flow parameter has no effect on the E value.

    I have verified this both experimentally, trying to modify a fixed thickness calibration cube --- and by examination of the E values generated in the g-code of some simple test shapes.

    Based on the above discussion, I can only concur that this is a bug. 

    After printing a dozen calibration cubes at differing flow rates on a .6 nozzle (as little as 50% flow) and seeing zero impact this was maddening.  This was verified by some very expensive measuring equipment.

    An M221 value inserted into the startup g-code fixes this and creates the appropriate reduction in flow rate.

     

    M221 S85 ; Set flowrate to percent


    After doing this my ability to print PETG went from almost impossible to results similar to what I am able to get with other filaments.

    One of the most maddening things about dealing with open source project maintainers is trying to convince them an obvious bug in fact exists.

    If you can point me to the unit test that handles checking the flow calculations I'll see if I can fix this one myself, or at least track down why it isn't working.

    Cheers!

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    Posted (edited) · Cura 4.6.1 Flow Rate Problems

    I'm not affiliated with Ultimaker or the Cura team.  I'm just an old retired guy (with a wide skill set) having some fun while locked in.  I have only been into 3d printing since December.  Of all the myriad complaints I've seen here, on Reddit, and on other boards, there have been two valid bugs noted.  The Cura team had been aware of both of them and were working on solutions.  It isn't perfect.  It isn't easy.  It works.

     

    The stl file for this Gcode snippet was sliced at 100% flow on everything using Cura 4.6.1.  4.7 beta gave the same results.

    ;FLAVOR:Marlin
    ;TIME:25985
    ;Filament used: 21.7041m

    ...

    ;TYPE:SKIRT
    G1 F300 Z0.2
    G1 F3600 E0
    G1 F3000 X115.451 Y31.869 E0.03186
    G1 X115.719 Y31.97 E0.0416
    G1 X116.554 Y32.373 E0.07316
    G1 X116.942 Y32.605 E0.08854
    G1 X117.473 Y32.969 E0.11045
    G1 X117.818 Y33.264 E0.1259
    G1 X118.068 Y33.497 E0.13753
    G1 X118.672 Y34.166 E0.16821
    G1 X118.805 Y34.342 E0.17572
    G1 X119.073 Y34.732 E0.19182
    G1 X119.724 Y35.782 E0.23387
    G1 X120.887 Y37.741 E0.3114
    G1 X122.288 Y40.026 E0.40262

     

    This Gcode snippet is the same stl file sliced 15 seconds later with the only change being 50% flow on everything with Cura 4.6.1.  Once again, 4.7 beta produced the same results.

    ;FLAVOR:Marlin
    ;TIME:25730
    ;Filament used: 10.6874

    ...

    ;TYPE:SKIRT
    G1 F300 Z0.2
    G1 F3600 E0
    G1 F3000 X115.451 Y31.869 E0.00796
    G1 X115.719 Y31.97 E0.0104
    G1 X116.554 Y32.373 E0.01829
    G1 X116.942 Y32.605 E0.02214
    G1 X117.473 Y32.969 E0.02761
    G1 X117.818 Y33.264 E0.03148
    G1 X118.068 Y33.497 E0.03438
    G1 X118.672 Y34.166 E0.04205
    G1 X118.805 Y34.342 E0.04393
    G1 X119.073 Y34.732 E0.04796
    G1 X119.724 Y35.782 E0.05847
    G1 X120.887 Y37.741 E0.07785
    G1 X122.288 Y40.026 E0.1006

     

    So there must be something in your settings.  (Initial Layer Flow doesn't update when the Flow is changed - could that be it?).   Any time I've changed the Flow in Cura, there has been a change in the E numbers in the gcode as witnessed above.  I do have to manually change Initial Layer Flow.

     

     

    Edited by GregValiant
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    Posted · Cura 4.6.1 Flow Rate Problems

    OK so when your printing olwith reduced flow go to tune menu and next to flow what does it say. Mine only changes from 100 if I set it in gcode. 

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    Posted · Cura 4.6.1 Flow Rate Problems

    Exactly.  Yes - you've got it!🍺

    The printer does not change unless it sees a Gcode M221 (or a change in the LCD flow - an internal M221).  That is a Global change to every E number that comes through the printer-planner.  It just doesn't care what those E numbers are.

     

    In my example above, if I print the 100% file the printer will say "Flow =100" and over the course of the print it will go through 21.7m of filament.

    If I print the 50% file the printer will say Flow=100 and over the course of that print it will push 10.7m of filament which is pretty near 1/2 as much (it's not exact because of other settings). 

    The E numbers in the first file were CALCULATED at 100% by Cura and the E numbers in the second file were CALCULATED at 50% by Cura and so are only half as big.  During the print of the second file, the printer will run 100% on E numbers that are 50% as big.

     

    Over here is the printer...over there is Cura.  They are separate.  Cura makes calculations based on your settings.  The printer is read-only but can make Global changes based on it's own settings and those settings can be changed either with lines in the Gcode, or by tuning a print on the fly from the LCD.

     

    Later we can get into Feed Rate which works the same way.  Right now though, I'm going fishing.

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    Posted · Cura 4.6.1 Flow Rate Problems

    Here is an example I ran printing with 100% and 80%.  I saved the gcode files back when I was having poor print results.

    This is a very simple 3d cube printed 'solid' (not in vase mode.)

    First 100% flow.

     

    ;FLAVOR:Marlin
    ;TIME:2575
    ;Filament used: 1.9831m
    ;Layer height: 0.2
    ;MINX:67.4
    ;MINY:67.4
    ;MINZ:0.2
    ;MAXX:132.6
    ;MAXY:132.6
    ;MAXZ:25
    ;Generated with Cura_SteamEngine 4.6.1

     

    Jumping to the end of layer 0

     

    ....
    ;LAYER:93
    ;TYPE:FILL
    ;MESH:cube.stl
    G1 F1800 X111.959 Y111.959 E1482.76082
    G0 F7200 X110.771 Y111.959
    G1 F1800 X111.959 Y107.524 E1482.94719

     

    Now with 80% flow

     

    ;FLAVOR:Marlin
    ;TIME:2575
    ;Filament used: 1.93164m
    ;Layer height: 0.2
    ;MINX:67.4
    ;MINY:67.4
    ;MINZ:0.2
    ;MAXX:132.6
    ;MAXY:132.6
    ;MAXZ:25
    ;Generated with Cura_SteamEngine 4.6.1
     

     

    ...
    ;LAYER:93
    ;TYPE:FILL
    ;MESH:cube.stl
    G1 F1800 X111.959 Y111.959 E1431.2997
    G0 F7200 X110.771 Y111.959
    G1 F1800 X111.959 Y107.524 E1431.48606

     

    Now for some math....

     

    Total filament used 1.93164 * 100 / 1.9831  = 97% (not 80!)

    Flow 100% Delta E on Layer 93 : 0.18637

    Flow 80% Delta E on Layer 93 : 0.18636

     

    0.18636 * 100 / 0.18637 = 99.99%

    One of the odd things is that these numbers CHANGE.  Just to not correct flow rates.

    Any ideas what could be going on here?  I have a fairly vanilla install with a non ultimaker printer.
     

    I think the only 'interesting' setting I have is Retraction Extra Prime Amount is set to 0.064.

    I have my filament diameter set to 1.75 and nozzle diameter 0.6.

     

     
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    Posted · Cura 4.6.1 Flow Rate Problems

    @SailMad Did you check all the flow settings?  There's flow settings for wall, infill, initial layer, and quite a few more.

     

    I see that the very last bit didn't change at all (0.186mm either way) but 3% decrease (instead of 20% decrease) means that 3/20 or about 15% of your print *did* experience less flow.  Maybe it was the outer shell only?   Or initial layer only?

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    Posted (edited) · Cura 4.6.1 Flow Rate Problems

    I clicked 'show all' related to flow. 

    It is interesting to note that the initial layer stays at 100 when I set flow to 80.

     

    image.png.2103b110bcf1ef6ac2c441de8c15af32.png

     

    Also note that in the above example I picked layer 93, to avoid any issues with the initial layers.  This is a simple cube.

     

    Edit : Looking at the preview - I'm guessing the line I chose for an example above is infill.

     

    My previous testing however was with a wall line, with similar results.
     

    Edited by SailMad
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    Posted · Cura 4.6.1 Flow Rate Problems

    3% could realistically be the raft or brim.

    Of  course if ONLY the raft had less flow that would be the opposite of what that initial layer flow setting would mean.  I'm stumped.

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    Posted (edited) · Cura 4.6.1 Flow Rate Problems

    In the interest of continuing this "I'll show you mine if you show me yours" thread...

    I'm attaching two project files.  They contain the same model (25x25x25 cube with no features).  Settings wise it's pretty vanilla with no skirt/brim and with infill at 100%.  One has all flows at 100% and the other has all flows at 50%.  When sliced in Cura 4.6.1 on my laptop the Gcode files turn out as I expected.  The 50% file uses half as much plastic.

    If you would be so kind as to open each of the files and slice them on your computer and show the results - maybe we can figure this out.  My expectations are that since we are running the same version we should come up with the same results.

     

    For reference - from my gcode file of the slice of the 25x25x100.3mf file:

    ;Filament used: 6.69192m

    and from my gcode file of the 25x25x50.smf slice:

    ;Filament used: 3.3331m

    25x25Cube50.3mf 25x25Cube100.3mf

    Edited by GregValiant
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    Posted · Cura 4.6.1 Flow Rate Problems

    Unfortunately I upgraded to Cura 4.7 and it wiped out all of my settings.


    The good news is that flow IS NOW WORKING in 4.7.

    Is this related to another setting?  I don't know.  I'll keep my eyes open as I am likely to set the same parameter a second time.

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    Posted · Cura 4.6.1 Flow Rate Problems

    I gotta believe it was a setting.  That makes more sense to me than your install of 4.6.1 being different than mine.

    Good to know it's sorted out (at least until you hit the right  wrong combination again!).

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