E3D Super Volcano and inconsistent flowrate



  • Hey all,

    Really happy with my switch over to Duet from Smoothie but hoping to get some input on some weirdness im observing. Basically, I'm observing my extrusion have occasional changes in the flow as it moves around the model if I print faster yet I see no skipping, I see no grinding of any sort it just seems like it has a hiccup as it does a long run as if it runs out of pressure for a slight moment.

    0_1558241901978_b7fe7087-ab95-4d4a-9093-1ecf7de5d56d-image.png

    The top print is what im aiming for while the bottom is what happens if I increase the speed. Here is a video of the difference and hopefully a visual of what I mean by it dropping pressure/flowrate and then regaining during the movement
    Good pressure/flowrate (top print): https://photos.app.goo.gl/A1xgDFJZVau12uRc6
    Bad pressure/flowrate (bottom print): https://photos.app.goo.gl/kADkoQBbMd6dCi677

    I get its alot of volume being moved but the Supervolcano has a claimed 165mm^3/sec and this is not reaching close to those levels. Both are printed with these conditions. Cooling is critical for printing at these thicknesses but it really looks as if it's not coming out of the nozzle nicely as oppose to failing to cool quickly enough causing slop.

    Nozzle size: 1.4
    Layer height: 1.0
    Extrusion width: 2.0
    Print temp: 240C

    The extruder motor is moving extremely fast during these prints and I'm almost thinking that to print with this nozzle size I might have to change the settings for my extruder config. Thinking that increasing the maximum speed might help in case it's potentially peaking. I have not done anything with regard to pressure advance at this point.

    M569 P0 S1 ; Physical drive 0 goes forwards X
    M569 P1 S0 ; Physical drive 1 goes backwards Y
    M569 P2 S1 ; Physical drive 2 goes backwards Z
    M569 P3 S0 ; Physical drive 3 goes backwards E
    M350 X16 Y16 Z16 E16 I1 ; Configure microstepping with interpolation
    M92 X59.26 Y59.26 Z2015.50 E415.00 ; Set steps per mm
    M566 X600.00 Y600.00 Z12.00 E120.00 ; Set maximum instantaneous speed changes (mm/min)
    M203 X18000.00 Y18000.00 Z180.00 E1500.00 ; Set maximum speeds (mm/min)
    M201 X3000.00 Y3000.00 Z20.00 E10000.00 ; Set accelerations (mm/s^2)
    M906 X950.00 Y2000.00 Z2000.00 E950.00 I30 ; Set motor currents (mA) and motor idle factor in per cent
    M84 S30

    Any thoughts would be greatly appreciated!



  • Where do you see 165mm^3/s?

    I see 110, and that’s pretty optimal situations. What material are you printing?



  • You're well beyond what I have tackled at the moment but ignoring the increase in speed and size if I saw finish like the lower I would initially suspect it was over extrusion.

    Have you checked your linear/non linear extrusion correction? Does the temperature plot for the hotend look consistant during these extrusions?



  • Edit: From your photos 30mm/sec print speed with 1mm layers and 2mm width is 60mm3/sec volumetric rate. I make that 1497 mm/min filament feed rate (3106rpm on the stepper) which is knocking on your maximum. Your extruder current limit, instantaneous speed, and max speed all look conservative compaired to some values we hear on this forum. Does your extruder motor run hot?

    Edit 2: I make the CSA of the 1.4 nozzle 12.25 larger than my 0.4. With that in mind a volumetric rate of 4.9mm3/sec would give a similar polymer flow speed out of the nozzle. Based on my current settings that would me about a 45mm/sec print speed. I'd say this doesn't have anything to do with the linear speed at which the polymer is coming out of the nozzle.



  • To me it seems that trying to print a 2mm wide line from a 1.4mm nozzle is asking for problems. How does it look if you print a 1.5 mm wide line?



  • @mrehorstdmd said in E3D Super Volcano and inconsistent flowrate:

    To me it seems that trying to print a 2mm wide line from a 1.4mm nozzle is asking for problems. How does it look if you print a 1.5 mm wide line?

    I regularly print 0.6mm wide lines using a 0.4mm nozzle so a 2mm wide line should be easy using a 1.4mm nozzle as long as the extrusion rate is reasonable.



  • As @elmoret has said the material is unknown. You may get away with oversized extrusion with PLA or ABS but I'd wager it'd be begging for a mess with PETG. This also all assumed the system is well calibrated too.

    Something else occurred to me. You say you are happy with the swap from smoothie. Was this working in smoothie or did you make a number of changes to the hardware at the same time?



  • @elmoret said in E3D Super Volcano and inconsistent flowrate:

    Where do you see 165mm^3/s?

    I see 110, and that’s pretty optimal situations. What material are you printing?

    Spoke with E3D live chat and I agree that is with optimal conditions as I found the 40mm3/sec for the volcano quite hard to achieve so I get that it would be lower. The issue I had with the volcano is that it really sapped the 40w cartridge power and couldn't maintain temps at higher flows but I'm not seeing any temp drops even at this volume yet. PLA not sure on the pellets used though.

    Edit:
    I've followed your thoughts on the true volumetric output of the volcano in the past and recently saw that you posted in the most ideal conditions its 40mm3/sec but you expect more like 20mm3/sec. What do you think the max rate would be for the volcano? 165 mm3/sec really unachievable and now that I think about it I didn't ask with what material they got that rating.



  • @doctrucker my thoughts as well and dropping to 85% extrusion multiplier did somewhat improve finish. However I have tuned my esteps and did find the stock bondtrch value to be pretty spot on. One thing I debated though was if I should have done the step calculation with a faster feedrate to be more reflective of what the large nozzle experiences think I used F90



  • ...also wanted to add that if you did request extrusion rates that exceeded the maximum it shouldn't cause any issue other than running slower than expected. The Duet will run a move according to the minimum acceleration, instant speed, or max speed ot the axis being moved.



  • @doctrucker said in E3D Super Volcano and inconsistent flowrate:

    You're well beyond what I have tackled at the moment but ignoring the increase in speed and size if I saw finish like the lower I would initially suspect it was over extrusion.

    Have you checked your linear/non linear extrusion correction? Does the temperature plot for the hotend look consistant during these extrusions?

    Sorry forgot to add the temperature plot looks rock steady during both print speeds.



  • @doctrucker said in E3D Super Volcano and inconsistent flowrate:

    Edit: From your photos 30mm/sec print speed with 1mm layers and 2mm width is 60mm3/sec volumetric rate. I make that 1497 mm/min filament feed rate (3106rpm on the stepper) which is knocking on your maximum. Your extruder current limit, instantaneous speed, and max speed all look conservative compaired to some values we hear on this forum. Does your extruder motor run hot?

    Edit 2: I make the CSA of the 1.4 nozzle 12.25 larger than my 0.4. With that in mind a volumetric rate of 4.9mm3/sec would give a similar polymer flow speed out of the nozzle. Based on my current settings that would me about a 45mm/sec print speed. I'd say this doesn't have anything to do with the linear speed at which the polymer is coming out of the nozzle.

    What would you recommend I raise vs keep the same? I was tempted to raise all the extruder settings but being rather new to duet wanted to hear what others thought.

    Sorry not familiar with the CSA, is that cross sectional area? I'll check on the extruder currently running it with 950mA



  • So do you have extrusion correction configured at all?

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M592_Configure_nonlinear_extrusion

    Most find that as you increase the requested filament feedrate there is a correction required to bring this up to requested. In other words request 100mm at say 1mm/min and get 100 but try the same at 40mm/sec and it may not be so accurate. There are exceptions and the three way diamond nozzle that I have needed no correction. It's easy enough to set up, but bear in mind if you want to test it you need to extrude while moving the nozzle.

    Check esteps first just moving filament through the extruder, not forcing through the hot end.



  • @burtoogle said in E3D Super Volcano and inconsistent flowrate:

    @mrehorstdmd said in E3D Super Volcano and inconsistent flowrate:

    To me it seems that trying to print a 2mm wide line from a 1.4mm nozzle is asking for problems. How does it look if you print a 1.5 mm wide line?

    I regularly print 0.6mm wide lines using a 0.4mm nozzle so a 2mm wide line should be easy using a 1.4mm nozzle as long as the extrusion rate is reasonable.

    In my limited experience with trying to print with 1 mm nozzles on volcano hot-ends, I have found that what works for small nozzles and line widths is not the same as what works for large nozzles and line widths. You're talking about vastly different volumes of plastic. If nothing else, the lines will cool at very different rates. While the much bigger line is cooling, the hot plastic is going to slump. With a smaller nozzle/line, the molten plastic viscosity/surface tension is going to have a bigger effect on the extrusion than it will with a larger nozzle and volume flow rate. I suggest tuning things up at line width = nozzle diameter and then try to go up in line width from there.



  • Normally you would find under extrusion as feedrate increases, but polymer can be weird and behave unexpectedly.

    While your extruder settings seem conservative I don't think they will be the route cause of your issue unless you can hear the extruder skipping or being back driven from time to time.

    Edit: this was following on from discussion on extrusion correction rather than replying to previous post.



  • @doctrucker said in E3D Super Volcano and inconsistent flowrate:

    As @elmoret has said the material is unknown. You may get away with oversized extrusion with PLA or ABS but I'd wager it'd be begging for a mess with PETG. This also all assumed the system is well calibrated too.

    Something else occurred to me. You say you are happy with the swap from smoothie. Was this working in smoothie or did you make a number of changes to the hardware at the same time?

    I slightly tested this on smoothie with an e3d titan but had some grinding pretty quickly so cut my losses and swapped to a bondtech and duet to rule out a few factors.



  • @doctrucker said in E3D Super Volcano and inconsistent flowrate:

    So do you have extrusion correction configured at all?

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M592_Configure_nonlinear_extrusion

    Most find that as you increase the requested filament feedrate there is a correction required to bring this up to requested. In other words request 100mm at say 1mm/min and get 100 but try the same at 40mm/sec and it may not be so accurate. There are exceptions and the three way diamond nozzle that I have needed no correction. It's easy enough to set up, but bear in mind if you want to test it you need to extrude while moving the nozzle.

    Check esteps first just moving filament through the extruder, not forcing through the hot end.

    Thank you for that! That does sound like something that would help. The real odd thing is during one round of printing I was able to get a near perfect print at the higher speed but for some reason, I'm unable to replicate it despite using the same gcode and same filament spool. When checking esteps without the hotend attached do you think speed of G1 E100 F90 makes sense or should I do it at a higher speed like G1 E100 F180? Or since the hotend is not attached would that really make a difference. I wonder if tightening the bondtech idler screw to its maximum point would have any positive effect on helping with backpressure and making the driving of filament any more consistent since it would bite it more.



  • When just checking the e-steps the machine can be cold. M302 can be used to allow cold extrusion ( https://duet3d.dozuki.com/Wiki/Gcode#Section_M302_Allow_cold_extrudes ). You will have to disable the interlock that prevents extrusion if the hotend temp is less than 170C. I run the e steps check slow, F60. F90 should work fine too.

    For the extrusion correction tests these need to be done through the nozzle at the working temperature. Search the forums. I do it manually, but I think someone has made a macro to ease the process.

    When giving the thinner extrusion widths a go it will be very interesting to see if the poor finish is fixed completely, if it still occurs when the print speed is increased to reach the same problematic flow rate, or there is no change.

    I'd probably check thinner widths first to see if that eases the main issues, but still check the e steps and non linear extrusion.

    Are you using standard extruder control or volumetric extruder control where the filament diameter is specified in the g-code?

    Edit: I should point out that I have an interest in improving machine to machine consistancy and a longer term interest in investigating both fine and thick nozzles. I've not worked with the volcano yet, just been held up on machine build and consistancy issues at the moment!


 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.