Inconsistent Extrusion?
-
Good luck with your rebuild. Note that 0.4 is a very high value for pressure advance. If you read this Duet FAQ article on pressure advance it says that moderate bowden systems might use 0.1, long bowden systems using 0.2, and direct systems as little as 0.05. Have you testing with settings in the 0.05-0.2 range?
Also, I and many others prefer to align the seams so that most of the print looks good and fairly uniform, and only that one seam looks bad. In S3D I'll usually position a print so that either a corner or the back of an object is oriented with point I specify as the one to align on. Also makes it easy to run tests like pressure advance on an object like a single-walled cube, with the seam on one corner.
Btw, I'm running some extremely challenging prints right now for a 3D-printed radio-controlled airplane, with complex parts using single-walled printing. After many test runs I've had to crank my pressure advance up to 0.25, which is higher than I've ever used before. I've got a very long (perhaps 650-700mm) long bowden tube. The bowden system is so "flexy" inside, given how much pressure is required for the filament to make the required flow rate, that I have to use a full 5.4mm of retraction. If you consider that a direct drive extruder would probably use maybe 1mm under similar conditions, that implies I get over 4mm of filament compression in my bowden tube, and all of that has to be retracted/unretracted with every nozzle move, complicating the start and ending of lines, etc. I've got my extruder speeds cranked up really high to help with this, and thankfully the BMG clone's dual extruder gears and my stepper seem up to the task. I really wonder how much easier (and better) my prints would be if I just went direct drive.
-
@sethipus My mistake, I mean S0.046 or S0.042 - I'm on direct setup
Have You tried Capricorn bowden tube? It has 1.9 mm inner diameter and it's much more precisely made than standard white bowden tube. So Your system will be less flexible. I was using it above 1 year ago when I was using bowden 3D printer and it worked a bit better. But the bowden was short, about 40 cm, so on larger tube like Yours it might help You more than me.That's the reason why I have build my printer with direct extruder. It's more accurate, less pressure problems etc.
-
@petrzmax yes I'm using Capricorn tubing in fact. I recently replaced my single-drive extruder with dual drive, and replaced the bowden tube at the same time because the one I was using before was so short that when the print carriage was in certain regions of the build plate I got very tight radius curves, which causes other problems. When I replaced the tube I went deliberately long, with the plan to cut it down a little after I've got some other things taken care of. I think I can cut down the tube by a good 100-200mm without getting too-small curve radius, since I also re-oriented the tubing a little. Hopefully when I cut the tubing down my bowden problems will reduce a little. Btw, I just had to stop a print of this wing panel and start a new one. I thought that the 0.25 pressure advance had solved my problem, but the problem was back. It's a combination of factors. What I'm seeing specifically is this single-walled print having underextrusion in the first few centimeters after the start of a new layer, leading to the layers in that region being incomplete. It's not a problem I see in my solid prints, but these single-wall complicated sparse parts are really tough to print well.
-
This is a stab in the dark, but can you please try setting
M566 P1? This sets the jerk policy to mimic a more Marlin like way of doing things, that applies the jerk value to more move types. At least that's my understanding.I assume you're running firmware 2.03.
-
@sethipus said in Inconsistent Extrusion?:
Good luck with your rebuild. Note that 0.4 is a very high value for pressure advance. If you read this Duet FAQ article on pressure advance it says that moderate bowden systems might use 0.1, long bowden systems using 0.2, and direct systems as little as 0.05. Have you testing with settings in the 0.05-0.2 range?
You do know the values on the wiki are too conservative right? This has been stated very often.
For example, for my 100mm Bowden volcano for ABS i need about 0.25, and for the same thing in PC i need 0.68
I suggest you tune the values according to this thread, not what the wiki states for some empirical values.
https://forum.duet3d.com/topic/6698/pressure-advance-calibration -
@phaedrux I'm using this command M566 P1. Models on photo were printed with this setting. Sure I'm on 2.03
-
In that case, have you tried with M566 P0?
-
@phaedrux Yeah, it was main setting at the beginning.
-
Which slicer are you using?
-
@phaedrux Idea Maker. But I was trying also Cura and S3D. Every slicer produced similar problems.
-
Hi again!
The parts have come yesterday and I have rebuilded and recalibrated my extruder. Also, I have switched to relative extrusion and x128 microstepping which I think helped a bit. Here are the results:
As You can see its much better and almost perfect. Almost, because now new lines have appeared. From my research I know that it's related to stepper settings. Changing TBL and TOFF had impact on this pattern. The question is does somebody made this lines disappear on TMC2660? I know that on prusa printers they can modify stepper waveform to make it disappear, but is there a fix for us, Duet users? I'm already on 0.9 deg motor with titan Aero.
-
@petrzmax said in Inconsistent Extrusion?:
Hi again!
The parts have come yesterday and I have rebuilded and recalibrated my extruder.
As You can see its much better and almost perfect. Almost, because now new lines have appeared. From my research I know that it's related to stepper settings. Changing TBL and TOFF had impact on this pattern. The question is does somebody made this lines disappear on TMC2660? I know that on prusa printers they can modify stepper waveform to make it disappear, but is there a fix for us, Duet users? I'm already on 0.9 deg motor with titan Aero.
I would try increasing or decreasing the stepper current a bit and see if that helps. You could also try to play a bit with the voltage regulator on your power supply , that changes the magnetic fields to be less ... interfering maybe and maybe gets rid of it.
Can you explain what you did when when you rebuilt the extruder? I´m chasing similar inconsistent extrusion problems to what you had before.
