@phaedrux i had updated to firmware 3.4.1 and left my jerk at 120 and acceleration at 500
After having trouble removing support with from prints with pressure advance turned off I turned it on and the seams the print were extremely wide.
After that print took 13 hours I decided to set both jerk and acceleration to 1000 and the seam issue seemed to mostly disappear.
Unfortunately, It didn't seem to have any other effect on the problem.
I tried to further increase jerk and acceleration with no change in the print.
This image has one print with pressure advance off and the other one with it enabled. Both the exact same gcode.
Latest posts made by jim546
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RE: Pressure advance causing reverse extrusion
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RE: Pressure advance causing reverse extrusion
It seems that increasing (yes, increasing) the acceleration and jerk values reduces the problem for some reason.
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RE: Pressure advance causing reverse extrusion
@phaedrux Just tested with firmware 3.3 with no change in how it prints this file.
Thanks for the suggestion
I think I'm going to try a full board reset to see if that fixes anything. If that doesn't work maybe I'll have to buy a new board. -
RE: Pressure advance causing reverse extrusion
Is it possible that something is wrong with my board? wiring? configuration?
is this problem repeatable for anyone else? -
RE: Pressure advance causing reverse extrusion
@deckingman The total / net extruder movement is negative 1mm of filament when printing testing 2.gcode.
A negative movement is expected when the printer slows down but it's also expected that when it speeds up there would be a positive extruder movement and the net movement of filament would be the same as without pressure advance. This is NOT what is happening.
The extruder is moving back as expected but is not moving back forwards when the extruder movement speeds up. This results in no filament being extruded or even net reverse extuder movement in this case.
The print works normally and has net positive filament feed when not using pressure advance.
The pressure advance of 1 was just random high value for testing to recreate the problem.
@Phaedrux I used the method here : (https://forum.duet3d.com/topic/6698/pressure-advance-calibration) to determine that .72 was the best pressure advance value. -
RE: Pressure advance causing reverse extrusion
I've revised the testing g code to get rid of the extruder priming moves and run it multiple times. Every time I run it with a pressure advance of 1 I get about a net negative 1mm of extruder movement. With no pressure advance I get a positive movement.
The results are repeatable and slowing down the acceleration or jerk does not seem to change them.
both extruders behave exactly the same.
testing 2.gcode -
RE: Pressure advance causing reverse extrusion
@dc42
This gcode recreates the problem.
new 1.gcode -
RE: Pressure advance causing reverse extrusion
@dc42
Board: Duet 2 Maestro (2Maestro)
Firmware: RepRapFirmware for Duet 2 Maestro 3.4.0 (2022-03-15) -
Pressure advance causing reverse extrusion
When using pressure advance on a model with multiple small surface details the filament retracts instead of extrudes.
disabling pressure advance solves the issue but has the expected issue of running a bowden setup with no pressure advance
I've tried lowering jerk to 50mm/m but it made no difference to the extruder movement.
the pressure advance is set to 0.72
no steps seem to be skipped as I can slow the print down to 1 percent speed and watch it slowly retract as it should be printing the small surface details.
I've been trying on and off to fix this issue for over a month so any help will be very appreciated.
Thanks
config(1).g -
RE: Occasional underextrusion
@phaedrux
I took the extruder off of the motor and reassembled it. The gear spins freely within the bearings when under load.
I've switched to the other extruder and haven't noticed it yet but I haven't had time to tried to try and cause it yet.