Requested speed is not reached
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@deckingman said in Requested speed is not reached:
600:3600:36
thank you. I wonder why we need these high values. Even the Ultimaker2 only uses 300mm/min for e-jerk?!?
see: https://github.com/Ultimaker/Ultimaker2Marlin/blob/master/Marlin/Configuration.h
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@puddingbaer91 said in Requested speed is not reached:
thank you. I wonder why we need these high values. Even the Ultimaker2 only uses 300mm/min for e-jerk?!?
So what? The Ultimaker2 also has a cantilevered bed that flops around like a field or corn in a breeze. Unless you set it on a concrete slab, you'll likely upset the layer height just by walking past the printer. So I wouldn't hold it up as being any sort of standard to which all printers must aspire (good marketing hype though).
On the subject of E "jerk", the only time it will come into play is either when pressure advance is used or if it is set lower than the instantaneous speed threshold of the X or Y motors. In that case, all it does is slow the entire print down. "Jerk" is the speed threshold to which axes and the extruder must slow down before a change of direction can occur. In RepRap firmware (which the Duet uses), "Jerk" is not applied to the start of a move from zero speed - only when the print head is moving and there is a change of direction. So before a change of direction can occur, the printer will slow down to the lowest "jerk" speed of either X, Y or E. So unless you want the print head speed to be controlled by extruder "jerk" rather than X or Y "jerk", then set it higher than those two axes. ("Axes" in this case is the plural of "axis" - not something that is used to chop wood)
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@deckingman said in Requested speed is not reached:
000
i made a video to show what my extruder sounds like with these high jerk values @ PA=0.6:
https://photos.app.goo.gl/jUapfqh28hwszUDT8
It's like the extruder will blow up in a few seconds.
Can't belive you print also with these sounds. Also the print is not possible as you see. Even with pa=0.1 it makes these sounds
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@puddingbaer91 None of my BMGs make that noise. The movement is visually the same as yours but not the sound. I'd say there is something loose somewhere. Maybe the hobbed gear on the shaft? Maybe the Bowden fitting inside the housing? Maybe worn teeth? Or maybe it's just the Bowden tube a bit loose in the fitting. You need to take the extruder apart and investigate.
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I guess there is also a chance that the motor current is too low to provide the required torque, causing the motor to skip steps when jerk is applied. What motor are you using, and what extruder motor current have you set?
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There should be nothing loose.
I use These ACT steppers:
https://www.roboter-bausatz.de/2554/act-nema-17-schrittmotor-17hs5425l20p1-x2
Current in Data Sheet is 3.1 Ampere
It's in German i Hope Google can helpCurrent ist set to 1300mA.
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see
https://duet3d.dozuki.com/Wiki/Choosing_and_connecting_stepper_motorsSo the usual practice is to set the motor current to no more than about 85% of the rated current. Therefore, to get maximum torque out of your motors without overheating them,
also
Duet 2 WiFi and Duet 2 Ethernet (maximum motor current 2.4A) => Stepper motor rated current <= 3.0A
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Okay Data seems to be wrong on the Website. My Motor ist labeled with 2.5A
https://photos.app.goo.gl/CSqKTi9TxJZBSTX27
Should i ran the Motors near 85% ? 2A?
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Thank you i will try and Report. But can't Imagine that this causes the Problem because the Motors are already very Strong at 1.3 ampere...
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tried with 2100mA but even with pa=0.1 the same sound but now only at high speed when printing infill. While printing slower the sound is now silent. Tomorrow i will try another stepper for extruder drive and report results
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okay also with another stepper (original from TronXY) i get the same sounds
Only reducing jerk to 600 will result in good sound -
@puddingbaer91 I say again that none of my 5 Bondtech BMGs make that noise. You said above that "there should be nothing loose" but have you actually taken it apart and checked?
Edit. The only reason why reducing "jerk" helps the sound is that it effectively reduces pressure advance so either don't use pressure advance at all or fix the problem with the extruder.
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Could you please Share a Video of your running Extruder? I de assemled my bondtech 100 Times also because switching Stepper Motor it seems all perfekt. Also the other Extruder (ultimaker Clone) Made These Sounds...it also makes this Sound with pressure advance = 0.1
Edit: i bought a bondtech BMG Clone to Check If Mine was faulty...
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@puddingbaer91 said in Requested speed is not reached:
Could you please Share a Video of your running Extruder? I de assemled my bondtech 100 Times also because switching Stepper Motor it seems all perfekt. Also the other Extruder (ultimaker Clone) Made These Sounds...it also makes this Sound with pressure advance = 0.1
Edit: i bought a bondtech BMG Clone to Check If Mine was faulty...
Taken just a few minutes ago and uploaded to my google drive folder.
https://drive.google.com/file/d/1oEaL72FOPDlCzU3uTm2UajcCdYBtXVWL/view?usp=sharing
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thank you this is what i expect from my extruder
May i found the problem:
https://photos.app.goo.gl/Krb1Pd1MatLy46S57
look closely to the metal gears. I tightened the screw to max and loosen it till it is possible to move the plastic gear (just a little bit. As you can see the spring is on block (compressed fully). The gears are slipping
if i loosen the srew much more this will also happen. I think this is not normal or what do you think? -
have you tightened the grub screw on the gear with the white gear?
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yes checked that. Here is also a video with cover (second bearing) mounted.
https://photos.app.goo.gl/PoWPArpmCjFiu4kH7
metal gears still slipping
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take the one with the white gear apart and post a picture of the shaft and the grub screw.
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@puddingbaer91 AFAIK that white gear is a press fit onto the shaft and it looks like it might be slipping. Take it apart and clamp the shaft firmly, then see if you can move that gear. It's likely to get worse the longer you print because of the heat conduction from the motor which will soften the plastic and /or make it expand more than the shaft. If that is the case, then you could try a it of epoxy adhesive or contact Bondtech and see if you can get new gear/shaft assembly (but make sure that is the problem first).
Edit - looks like we weer both typing at the same time.
