Volcano hitting extruder limit?



  • I've just setup my Flashforge with a E3D volcano mounted on a Titan aero with a Pancake stepper . I've been struggling all day with under extrusion and in the end steps skipping on my motor. When I reduce speed everything is fine.

    I've calibrated my steps/mm and set M92 E802 in my config file. I then did two walls on a 20x20 cube and set extrusion multiplier down to 0.92 to get that spot on. Max speed on stepper is 3600mm/min and that should be 105mm^2/s and plenty for the volcano if I'm not mistaken. 16x microstepping on all motors. I had my stepper amps set to 1000mA but increased to 1100mA for testing without any luck.

    All testing has been with 0.8 nozzle. I started out with recommended 0.96 layer width in simplify 3d and increased the layer height to 0.6. Temperature at 225 and I'm printing PLA. Print speed "base" set at 60mm/s with reduction of 80% for solid infill and 50% for outline. With this setting I'm at 28mm^2/s volume for the solid infill and it should in theory be within spec of volcano that maxes out at 30-40 from what I can figure out when googling. I have to recude speed down to max 20mm/s and the print quality improves.

    What is limiting me here or what am I doing wrong? Do I hit some kind of limit in the Duet in regards to microstepping? Max speed of the stepper?

    Link to stepper documentation
    https://www.omc-stepperonline.com/download/17HM08-1204S.pdf?fref=gc&dti=1430499967168262



  • The usual setting for an E3D titan is around 400 steps per mm at 16X microstepping (my 5 are between 393 and 403). Did you perhaps calibrate them using 32X microstepping? That would explain your figure of 802 but if you are now using 16X microstepping, you'd need to halve the steps per mm.

    Edit, you are nowhere near the limit of what the electronics or steppers are capable of. This little test I did may be of interest https://somei3deas.wordpress.com/2017/06/22/exploration-of-print-speeds-with-a-diamond-hot-end/

    Second Edit. Just noticed that you are using 0,9 degree steppers so your steps per mm at 802 will be correct.

    HTH



  • Bump up the max speed on the extruder. 6000+ won't hurt anything.



  • No not for XY movement but looking at your mm^2s I'm above those numbers with similar nozzle. I see that you are down at 195 degrees also. I'm doing a testrun now at 240 to see if I get thicker walls with 240 than 230 and all other parameters the same. I had good numbers on a 20x20mm cube now but then the speed is limited by the layers (slows down to keep X layer time). Once I inreased to 40x40 cuber it dropped from 1.92 for two walls of 0.96 to 1.89. Looks related to extrusion speed but I'm a total newb on volcano so what do I know ๐Ÿ˜„



  • @number40fan:

    Bump up the max speed on the extruder. 6000+ won't hurt anything.

    How can I calc how much speed it will reach? I tried calcing from steps/mm and figured I would never even reach 1/3 of what I had set it to now but this is the first time I'm doing calcs on this so I might have missed a important step somewhere



  • Last test. I just calibrated extrusion so it's slightly over extruding when measuring two walls at the same 40x40 cuber I'm printing here. Then I tried to print it with infill and this is how it looks like. Speed is 50mm/s, 50% reduction on outline, 80% reduction on solid infill and 25% reduction on first layer (first layer is looking great). Layer height 0.5mm and width 0.96mm. This should give me 19.2mm^2/s and should be within what volcano handles but It's not ๐Ÿ˜„ Hob is really thight on the extruder and I can't spot it skipping on the hob but hard to tell really.

    The infill settings is 100%, 100% infill extrusion width, 15% outline overlap (doesn't look like it) and temps is 225 for first layer and 235 for next layers. Notice how it's worse in the middle once speed picks up on the longer stretches.



  • @minim:

    @number40fan:

    Bump up the max speed on the extruder. 6000+ won't hurt anything.

    How can I calc how much speed it will reach? I tried calcing from steps/mm and figured I would never even reach 1/3 of what I had set it to now but this is the first time I'm doing calcs on this so I might have missed a important step somewhere

    I don't know the calculations. I do know that setting it higher than it will be able to reach, won't hurt a thing. I see them being there as a safety buffer. I have my X, Y and Z set to 20000, but I know I'll never get that high.



  • You've simply hit the limit of the melt rate IMO, despite what you may have read on Google. Try a higher temperature.


  • administrators

    A pancake stepper may be sufficient for a Titan feeding a normal V6 hot end and 0.4mm nozzle, but I wouldn't expect it to be powerful enough for a Volcano. The fact that it is skipping steps confirms this.



  • I run a volcano from 20mm pancake stepper I'll try to replicate this.



  • I can't go any higher. I tried 240 and then it started popping and the layers looked really bad. At 230 I can print but if I slow down to much it starts looking like the 240 layer. 225 seems to be the absolute max I can do without damaging the PLA.

    I should notice the skipping steps tho shouldn't I? Once I turned down speed it doesn't skip steps like before but it underextrudes a lot like the image shows.

    That would be great DjDemonD! If you can't replicate it I'd love to know the tricks of getting more plastic through it. Do you have a sock on it?



  • Okay so PLA printing at 205 deg C (pt100 so should be accurate), bed at 70 deg C.
    Setup is corexy with titan aero, 20mm nema 17 pancake motor at 700mA
    Extruder at 444 steps/mm (1.8 deg) accel 1000, jerk 20
    XY accel 2000
    XY jerk 600

    This Layer printed at 50mm/s infill (speed 100%)

    So no under extrusion here the layer time was 87 seconds
    Its 40x40x0.2mm = 320mm3
    so this gives an extrusion rate of 320/87 = 3.67mm3/s

    This layer printed at 70mm/s infill (speed 140%)

    No under extrusion here either (sorry a bit of black is coming through which was loaded before the white) layer time was 65 seconds
    Extrusion rate 4.92mm3/s

    This layer printed at 90mm/s infill (speed 180%)

    Still no under extrusion though it is a little less even surface

    Layer time 54 seconds, extrusion rate 5.92mm3/s

    Now were getting seriousโ€ฆ 110mm/s (speed 220%)

    still no under extrusion
    layer time 47 sec, extrusion rate 6.8mm3/s

    So I got bored and ramped it right up this layer printed at speed 550% (roughly 275mm/s but my acceleration settings are probably limiting the shorter extrusion lines)

    There is a bit of patchiness in the middle of the infill now
    layer time 35 seconds, extrusion rate 9.14mm3/s

    I did go faster but the layer time did not decrease so I'm at the limit my acceleration settings will allow.
    In case anyone doubts how quick it was going here's a video of it at "275mm/s" extrusion rate 9mm3/s

    https://youtu.be/H8pe_xal2FQ

    All this with my 20mm pancake stepper at 700mA current, and only warm to the touch, the hotend maintaining 205 deg C throughout.

    So not sure what the issue is Minim?



  • Yes I have a sock on it.

    Go back to basics, how easy is it to push the filament through by hand? It should flow through with little/no pressure?
    Maybe you have a bad nozzle? Can you use micro drill bits to size the nozzle precisely?

    I probably ought to say this wasnt even a genuine titan aero but a triangle labs clone!

    Also verify the hotend temp is correct using IR thermometer (colour one side of the heater block in black) or use a k-type thermocouple probe.



  • But this is 0.2 layers tho. What width? I'm doing over double the layer height. But that was some crazy speed ๐Ÿ˜„

    40x40x0.5 is 800mm3 so even at the slowest layer I'm trying to extrude more plastic than you did at the peak. 87seconds would give it 9.19mm3/s.

    I tried warming it to 220 now and it flows good when I barely push it. I don't have micro drill bits but I have 1.2 nozzle and 0.6 nozzle I could try.

    Tried to test temp now but my FLiR camera didn't like that hot temperatures ๐Ÿ˜„ It did show that there where big temperature differences in the block/nozzle/heater tho but it could be because I just heated it up. Since it's heated so much that the PLA started bubbling and getting nasty surface when I upped it to 234-240 wouldn't you think it's hot enough?



  • 19mm^3/sec is normal performance for a Volcano depending on the material. Some materials flow more easily than others.



  • Yes if I was using a 0.6 or 0.8 nozzle I'd expect to hit the melt rate limit at about 50-60mm/s infill speed. I was using 0.4mm nozzle.

    You could probably edge a bit more out of it with a bondtech extruder, use of higher wattage heater cartridges (e3d supplied cartridge with my volcano eruption pack was only 23w) I've got some 50w cartridges on order, sure they're more of a fire risk but assuming you can transfer the heat to the filament you aren't being limited by the heater, I wonder if e3d make a copper volcano block? Use thermal transfer compounds in the right places also, ie everywhere except between block and heatbreak.



  • @DjDemonD:

    Yes if I was using a 0.6 or 0.8 nozzle I'd expect to hit the melt rate limit at about 50-60mm/s infill speed. I was using 0.4mm nozzleโ€ฆ............................

    Simon,

    As well as 0.8 mm nozzle, the OP is also using a 0.5mm layer height. If your tests were done using 0.2 or 0.3, then the melt rate limit will be around half the 50 to 60 that you'd expect, so somewhere around 20 to 30? Not only that, the area of a 0.4mm nozzle is 0.12568 mm^2 but a 0.8 is 0.50272 so around 4 times the area. So if his max print speed is about an eighth of what you were seeing with a 0,4mm nozzle and 0.2 to 0.3 mm layer height then he's doing well.

    Ian



  • I suppose you have a 40W cartridge installed?
    Melting rate can be ok, but one should be capable to supply the heat needed to melt the stuff.
    I never had issues with that.
    Using : Volcano with 24V 40W heater, 0,9ยฐ full blown stepper @ 800mA. Direct feed with an Aero.



  • I have a 24V 30W unit installed and heat doesn't seem to be an issue since PWM isn't 100% on for the heater output. It's keeping the temperature steady while printing and I actually had to reduce from 240 degrees when I was testing that as the plastic "burned" and had a bad surface finish. I don't understand how the heater could be to small then. What nozzle/speed/height are you printign with WalterSKW?

    A friend is sending me a sock now and I hope that might help if the temp in the volcano can be held more stable through the whole block.

    As to the nozzle size layer height. I'm not sure things scale linear as you increase. Would be great if anyone running a 0.8 nozzle could do a quick test at 0.6 layer height and 0.96 width just to confirm if it is indeed a extrusion limit. It might not look as a big difference but printing with 0.6x0.96 is really a HUGE amount of plastic compared to 0.3x0.46 that I had with 0.4 nozzle. The reel almost spins back there as I go ๐Ÿ˜„ Just Wish I could get it more stable and without under extrusion ๐Ÿ˜•



  • I once did a simulation about the melting rate and the heat (power) needed for melting PLA with different nozzle sizes and speeds.
    This was the resulting table :
    https://www.dropbox.com/s/i71rx2nlfpjfcuf/Melting%20rate.png?dl=0


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