RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Not so sure - the fan is moving air across the heater block and and removing calories from the system. At 40w, there are only so many calories. Unless there is some other limit on heat exchange that makes 40w unimportant (i.e., 30w is enough to exceed some thermal exchange limit).
40W equates to approximately 70 mm³/s of molten PLA plastic (20°C→200°C, incl. phase change*, see my earlier post). For 15 mm³/s, 10W would be enough. The next major heat loss is through the heatbreak, but still way below the available 40W.
(* Actually fusion heat, since plastics don't have real phase changes.)
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Folks - to get a base line: can we all agree on how this this command set functions.
The idea is to extrude a trace 200 mm long, and dispense 10 linear mm of filament, in one second.
G1 X25.00 Y105.00
G1 X225.00 Y105.00 E10.000 F12000
ps: further, that this is apprx 24 cubic millimeters of material (1.75 mm diameter).
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
My concern with using the slicer is the magic going on under the hood of the slicer software for acceleration, jerk and linear advance to derive those extrusion rates. Change the length or speed and you have to re-calculate the extrusion amount to get the same results. That's why I've gone with free-air extrusion and avoided the slicer.
- For an extrusion 0.2mm high X 0.4mm wide X 200mm you're pushing 16mm^3 of filament.
- Dividing 16mm^3 by the area of the cross-section of 1.75mm filament (0.875) yields roughly 6.65mm of 1.75mm filament to print 16mm^3.
Or else I'm doing it wrong. I'm probably doing it wrong.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
No experience so far. They're just on my list of possible upgrades for the printer.
Inland is a good economy choice for the US, but I'm not sure about world-wide availability. ColorFabb is great stuff, but a bit pricey to ask someone to buy just for testing. Is eSun readily available world-wide?
No Inland available. eSun is, but it's not a major brand in Europe. But there are 20+ filament producers around, I compiled a list a while ago, then lost it because I closed the page. 🙂
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Folks - to get a base line: can we all agree on how this this command set functions.
OK, I think I understand where you're going. We're not using a slicer at all, correct? (Good.)
The idea is to extrude a trace 200 mm long, and dispense 10 linear mm of filament, in one second.
G1 X25.00 Y105.00
G1 X225.00 Y105.00 E10.000 F12000ps: further, that this is apprx 24 cubic millimeters of material (1.75 mm diameter).
My always-debatable math skills tell me E10 (10mm) X 2.405 (area of 1.75mm filament cross section) = 24.05mm^3. My question is knowing how long it will take for the printer to actually execute that command. We're telling it to move at 12000mm/min (20mm/s) but firmware acceleration, jerk and linear advance settings may still apply. It's the influence of these on physical moves that has me wary of doing any moves.
But then... I'm probably missing something!
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Folks - to get a base line: can we all agree on how this this command set functions.
The idea is to extrude a trace 200 mm long, and dispense 10 linear mm of filament, in one second.
G1 X25.00 Y105.00
G1 X225.00 Y105.00 E10.000 F12000ps: further, that this is apprx 24 cubic millimeters of material (1.75 mm diameter).
To do that, you probably want:
G0 X25.00 Y105.00 ; non-printing move to 25/105
G1 F12000 ; set speed to 200 mm/sec (12000 mm/min)
G92 E0 ; reset extruder position to 0
G1 X225.00 Y105.00 E10.000 ; move and extrude
But yes, I think you've got the math right. Assuming youre 0.20mm above surface, the width should be 0.60mm.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
My always-debatable math skills tell me E10 (10mm) X 2.405 (area of 1.75mm filament cross section) = 24.05mm^3. My question is knowing how long it will take for the printer to actually execute that command. We're telling it to move at 12000mm/min (20mm/s) but firmware acceleration, jerk and linear advance settings may still apply. It's the influence of these on physical moves that has me wary of doing any moves.
But then... I'm probably missing something!
No, you're quite right. Since printer limits will still apply, this will take more than a second and only the peak speed will be 200 (not 20) mm/s.
If we wanted to test this while printing, the best would be printing a spiral vase of a large diameter at a given speed. Then the printer can sustain the maximum speed for a long time.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
If we wanted to test this while printing, the best would be printing a spiral vase of a large diameter at a given speed. Then the printer can sustain the maximum speed for a long time.
Hah! No, I'm sticking with free-air extrusion. I'm trying to avoid the firmware doing anything to "help".
I hate the way the inability to edit posts makes us (and by "us" I mean "me") look like morons for simple mistakes that we catch minutes later. Thanks for the catch on 200 vs 20.
But surely the nozzle aperture comes into play at some point. I know the recommendation is to extrude sufficient material (50mm+) to relieve any back pressure due to the nozzle, but does the nozzle influence zero out once flowing? I'm going to swap in a 0.60mm nozzle next and repeat testing.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Well, I suppose Prusament is a possibility... I don't think they have a natural/uncolored flavor available though. The sparkly filler might influence results.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Voj - this is right up your alley: find the error in this:
G1 X200 Y0 E6.652 F12000 ; extrudes 6.652 mm of filament in a trace 200 mm x 0.2 mm x 0.4 mm (16 mm3)
The theory: print 200 mm at 0.2 mm x 0.4 mm, requires 16 cubic mm material. Or 6.652 lineal mm of filament.
D [mm] Sբ [mm²] lₑ [mm] hₑ [mm] wₑ [mm] Sₑ [mm²] V [mm³] Q [mm³/s] lբ [mm] v [mm/s] v [mm/min] 1.75 2.405 200.00 0.200 0.400 0.080 16.00 16.00 6.652 200.00 12000
Except for the fact that you'd need to be in G91 relative mode, it should work as you expect. The whole move would take 1.20 s, because of max acceleration of 1000 mm/s set in the printer. The average extrusion rate would then be 13.3 mm³/s.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
So many mistakes that I have to leave behind just because I don't want to create another post just to fix them *cringe*. And I've done the 200 vs 20, too (with thermal conductivity). 🙂 So it's "us", really.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
We want M83 extruder relative and G90 absolute moves do we not?
@tim-m30 caught my startup gcode goof with not setting extruder relative mode.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
We want M83 extruder relative and G90 absolute moves do we not?
@tim-m30 caught my startup gcode goof with not setting extruder relative mode.
Overall yes. Tim's example either needed G91 or starting at [0,0].
Btw, as another datapoint, I just tested Prusa (Filament-PM, Plasty Mladeč) PETG Black, the standard one which is used for printing MK3's, and I've achieved F510 at standard 230 °C without clicking on my printer. That translates to 20.44 mm³/s. But then, the BMG is a rather powerful extruder.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
FYI to all, the official E3D specs for volumetric rate is damn hard to find. I did find this E3D write-up of the SuperVolcano that has details using scaled-up Benchy prints for comparison: https://e3d-online.com/blog/2019/02/28/supervolcano/
Of course, everyone has a different name for it. E3D refers to it (at least here) as "Nominal Volumetric Throughput" measures in mm^3/min. No wonder it's so hard to find good data.
The only common nozzle size used for all 3 extruders is 0.8mm for the 500% Benchy prints. Quick comparison:
- V6 with 0.8mm nozzle is rated at ~14mm^3/s.
- Volcano with 0.8mm nozzle is rated at ~19.5mm^3/s
- SuperVolcano with 0.8mm nozzle is rated at ~24mm^3/s
This did answer one of my questions: Nozzle size does impact throughput, which only makes sense. So with the 0.80mm nozzle being the largest official E3D size for the V6, their advertised 15mm is close, although with a 0.40mm nozzle it drops to closer to 10mm^3/s.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Btw, as another datapoint, I just tested Prusa (Filament-PM, Plasty Mladeč) PETG Black, the standard one which is used for printing MK3's, and I've achieved F510 at standard 230 °C without clicking on my printer. That translates to 20.44 mm³/s. But then, the BMG is a rather powerful extruder.
This is going to be one of those things where there are safe numbers to recommend to the average new user that will (hopefully) keep them out of trouble (I'm sticking with 11.5 for now), and then there are the tuning numbers for those of us trying to extract every bit of performance out of our printers (15-20 depending on hardware configuration with the v6?).
I'm like the yellow speed sign showing a maximum speed for that big turn ahead of 40. You know you can do 80.
As expected, that printing temperature makes a difference, and a significant one. Do you normally print that filament at 230C? I do wonder how much the extruder matters. Yet another factor to consider!
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Okay - real data.
Test is basic: extrude N material over 200 mm in 1 second.
Test process was to lay down 12 pads of base material, 5 stripes of 200x0.2x0.4mm. Then extrude one 200 mm test strip in the middle of each pad. The base pad size is 200 mm x 2 mm. The test strip is per table.
I tested a variety of rates from 12.0 up to 33.5 cubic millimeters per second. Data table shown for 28-33.5 mm3/s, and result images shown only for 22-33.5. 22.0-27.5 mm3/s was done at 95% extrusion (oops). 28.0-33.5 mm3/s done at 100%. I have verified the weight of the samples and confirmed the 22.0-27.5 tests are indeed the proper amount of plastic (to the accuracy of my milligram scale in free air).
Conclusion: Test strips above 30 mm3/s seem to be having difficulty in maintaining a constant extrusion size, with 33.0 and 33.5 even sputtering at the extreme end of travel. I am not sure what to conclude from that. But tests to 27.5 mm3/s appear to be well formed and quite usable. However, I have not methodically measured extrusion widths to verify they are as expected.
22.0 - 27.5 Test
28.0 - 33.5 Test
Earlier ad-hoc tests I performed using brute force extrusion to determine the point at which the extruder gear began skipping, showed a limit of about 18 mm/s. The tests shown here do not approach that speed, ending at just under 14 mm/s for the 33.5 mm3/s test.
[mm3/s]
Example gcode for the 12th test strip at 33.5 mm3/s:
G92 E0.0 ; 12
G1 X25.00 Y105.00 F10800
G1 Z0.40 E0.80 F2100
G92 E0.0
G1 X225.00 Y105.00 E13.928 F12000
G1 E-0.80 F2100
G1 Z1.00 F10800
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
As a postscript, the above is a burst test. I am trying to put my head around a continuous test. But need to spend time on a model - I definitely don't want to hand code 10,000 lines of gcode. lol.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
A few more observations from the E3D 500% Benchy test:
- Swapping a V6 0.40mm nozzle for a 0.80mm nozzle knocks 10 hours off total print time.
- Swapping a V6 with a 08.0mm nozzle mounted for a SuperVolcano "only" knocks another ~4 hours off total print time.
- The big gain with the SuperVolcano is when you jump to nozzles of 1.00mm or larger.
Simply swapping nozzles is a very cost-effective, low-effort way of boosting stock i3 Mk3 performance.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
Bob - changing layers from 0.25 to 0.35 is a major part of the V6 gain (30% faster, right there), probably as much as the increased diameter. Pretty sure there are printers out there that make a Super Volcano setup look lame, too. But I have neither the time, interest, nor money to pursue such.
My goal here is to better understand why people are saying 15 mm3/s is unrealistic for a V6 on my Mk3 ... lol. So far, I haven't convinced myself Prusa choose a wrong number. Though I also have to say I have seen some effects that I did not understand at the time, and probably still don't understand. Were they volumetric limits? Maybe; but they also could have been the silly Prusa heat break mod.
RE: Slic3r PE: Please reduce default values for "max volumetric speed" from 15 to 11.5 mm³/s
So - thinking I'll do a slow speed test, moving kilograms of filament at limiting rates directly on to the hot bed. Separate strips 1.5 expected extrusion width, printing at 25 mm/s or whatever the standard layer 1 rate is. If I modify a standard 100 mm square with 20% rectilinear infill I should be able to punch up the extrusion to make an acceptable test. It will look messy but the infill is a continuous pour, suitable for continuous extrusion rate testing..