Volcano hitting extruder limit?
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I run a volcano from 20mm pancake stepper I'll try to replicate this.
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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?
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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 600This 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/sThis 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/sThis layer printed at 90mm/s infill (speed 180%)
Still no under extrusion though it is a little less even surfaceLayer time 54 seconds, extrusion rate 5.92mm3/s
Now were getting serious… 110mm/s (speed 220%)
still no under extrusion
layer time 47 sec, extrusion rate 6.8mm3/sSo 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/sI 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/sAll 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?
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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.
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But this is 0.2 layers tho. What width? I'm doing over double the layer height. But that was some crazy speed
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
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.
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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.
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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…............................
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
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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, 0,9° 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
Just Wish I could get it more stable and without under extrusion 
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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 -
Most of the time I print with a 0,6mm nozzle and very often at 0,4mm layerheight. Speeds are between 70 and 150mm/s.
Never had an issue.
For my stepper : I lowered current until I ran into issues and then increased to the 800mA mentioned.
I pull the filament from the roll on top of the printer through a PTFE tube (approx 800mm long)
See a bit on my setup on here : https://www.youtube.com/watch?v=LzoJNzgA9xc
This was the first print so it was a bit slower. This one is faster at 260°C and 0,4mm layers https://www.youtube.com/watch?v=Kb-xLqPqvMo
Both with a 0,6mm nozzle.
I could do a test with a 1.2mm nozzle, the largest I have or a 0,8mm one. -
@minim. Just a thought - are you using a print cooling fan? If so, try turning it off. Even if it's not blowing directly over the nozzle, cold air can be deflected back from the bed or the object itself. The other thing you could try is a premium PLA. They often print at lower temperatures that some "generic" PLAs. (but I still think that will using a 0.8mm nozzle and 0.5mm layer height you've hit the melt rate limit).
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I would be very interested in seeing a test on 0.8 or 1.2 WalterSKW if you got time for it. I'm also tempted going down to a 0.6 nozzle just to test if I can get rid of this speed limit that way. I have my stepper set at 1100mA now
@deckingman Yes, but not before layer 3 and up and these issues shows from layer two. I tried disabling it completly also while testing just to avoid this. A friend just put a volcano soc in the mail for me so tomorrow I will give it a go with sock on it.
Just a sidenote here. With a 1.8degree stepper end the 30:1 reduction gearing in Zesty nimble will that be close to the speed limit of the stepper motor on duet wifi with 16 microstepping? I'm considering those remote direct and it should give me more power also.
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Depends on the motors inductance, low inductance motors at 24v can spin pretty fast.
My attempts to print things with big nozzles didn't really save me great deal of time as you do run into the limit of what you can melt at around 50mm/s, but they did produce some very tough objects, one is a toy for my son it must have been dropped onto a hard floor from 60cm about 50 times and hasn't broken yet.
Interesting to know what is limiting the melt rate, if its not insufficient wattage (which I can test as soon as my 50w heaters turn up), then it must be the length of the melt zone. Maybe someone fancies machining a longer block than a vocano?
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One of the differences between a Volcano and a V6 besides the length of the nozzles is that the heater cartridge in a Volcano is better placed as it is parallel to the melting zone and the heat can travel a more efficient path.
Larger (longer) melting zones have their disadvantages too, as there is a higher mass of liquid plastic that wants to ooze out of the nozzle.@DjDemonD : Where did you find the 50W heater?
@minim : any preferences for a test?
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aliexpress, https://www.aliexpress.com/item/6x20mm-24v-50w-printer-cartridge-heater/32609747337.html
the vendor even measured the resistance for me 11.5 ohms, so they should actually be that wattage, but I haven't received them yet. -
One of the differences between a Volcano and a V6 besides the length of the nozzles is that the heater cartridge in a Volcano is better placed as it is parallel to the melting zone and the heat can travel a more efficient path.
Larger (longer) melting zones have their disadvantages too, as there is a higher mass of liquid plastic that wants to ooze out of the nozzle.@DjDemonD : Where did you find the 50W heater?
@minim : any preferences for a test?
That 40mm Cube would be fine since We can compare it. O4 vs 08 nozzle.
I really dont see how more watts would solve anything as it's no trouble keeping the temperature as it is now with a 30w. The controller won't put more watt through a 50w heater than a 30w heater if it's the same temp goal. PWM duty cycle will be reduced tho but as long as it's well below 100% how will it help?
Edit
Regarding strength of a print. The ones I'm printing now is height calibration blocks for a 2500kg Range Rover so I'm resting over 500kg on each block that is 30mm diameter. Works great with 25% infill -
To bad E3D havent made copper Volcano blocks yet. Maybe that could give you a few percent more.
I also saw that they have socks now for Volcano
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Would it help to use heat paste from nozzle to the block to improve heat transfer to the nozzle or is the limit the area of the melt zone touching the palstic?
