Weird corner behaviour

General Discussion
41

Its layer by layer. entire z height for any 90 degree corner.
I haven’t checked my backlash super recently but you typically expect to see artifacts/inconsistent extrusion, whereas i see very clean faces.
I’m not sure how retraction would affect this since there are no retractions for 3 of those 4 corners, and in any case its set to pretty standard settings and looks good on multi part prints so I wouldn’t expect that to impact this either :confused:

Edit: outer perimeter acceleration of 1000, speeds of 70 - 80 mm/s.

42

I have no real idea but I would believe that it is either:

  1. a mechanical thing
  2. a slicer thing
  3. a slicer + Klipper setting thing
  4. a combination of 1. and 2. and 3.

Slicers also have settings that do similar to PA and stuff like coasting etc. I do not know how, but I’d guess some weird combination out of such settings, potentially coupled with PA could be causing this.

1 Like
43

Its not #2- showed up for me across 2 slicers with no settings changed to my knowledge.

My best guess is also mechanical, but it seems strange that this artifact only shows up on hard 90 degree corners, I’d expect something else to be out of whack.
Again, can’t be PA.
If there was something other then input shaping within klipper that impacts smoothing thats seems quite likely, but with input shaping disabled it still occurs and im not sure what else would even matter. SQV remains unchanged from before i had this artifact to now

1 Like
44

I am having literally exactly the same problem. It started happening about a year ago, for no apparent reason. I have similar directional corner bulging regardless of PA values. Higher PA values just end up ruining my print quality and not fixing the corners. All belts are tight, everything is clean, tried a variety of print temperatures etc… nothing is fixing it. It really does seem like X and Y vs Extruder are out of sync.

45

There are dozens of us!
What board are you running and what are you running klipper from?
I currently use a linux laptop and was going to try switching to a pi
I saw someone tried switching out steppers to no avail, but I have one so I may give that a shot replacing the X or Y one by one

46

I have a CR6-SE with BTT SKR CR6 board, using a RPI 4 running Klipper. I already adjusted pressure advance smooth time, square corner velocity and many other parameters… and i still have corner bulging (overshoot) in the direction of travel.

47

I wanted to give the group another update. I did the following to see if i can fix my corner overshoot problem, that isn’t going away with PA:

  • I turned off stealthchop and interpolation on all my TMC2209 stepper drivers.
  • I set the microstepping to 64 for all axes and the extruder.
  • I ran the hotend temperature very hot, and cold.
  • I recalibrated my E-steps.
  • I am already using capricorn tubing in a Bowden configuration and checked that there was no movement of the tube during printing.

I am out of options here. It really does visibly appear as though the pressure advance is not synced with the motion planner.

48

Hi,
i did the same and many more things. Almost one year after starting this thread i still have not found a solution for this.

I still think there is something out of sinc at hard corners. Even without PA enabled

49

Strangely enough for me the printer printed great with Klipper about a year and a half or more ago. I only started having this PA behavior about a year ago, as though it was associated with a firmware update at that time.

50

I may try swapping my X/Y motors one by one. Is there any way to get the Gcode of a print post firmware adjustments? that shows all the exact acceleration changes and pressure changes applied by klipper machine limits, pressure advance, and input shaping?

51

Hi.

Well, i have installed Marlin and configured it. No change in indent before corners.

I think it has nothing to do with the firmware…

52

This is at least some good news!
So you can just concentrate on the mechanical part of your printer.

Just to have things up to date:

  • The issue is present with a model in vase/spiralized mode as well so we can exclude any retract/feeder issue?
  • It does not matter if the acceleration is high or low?
  • It is present on high or low print speeds too?
  • Is it present on X and Y or only on one axis?
  • Does your print head or the nozzle wiggle in X or Y?
  • Do you have the input shaper graphs of X and Y?
53

From what I saw at least this is consistent across accelerations and print speeds, present on both axis, with no discernible wiggle and good input shaper graphs. I think someone mentioned they got some change with higher speeds but I’m not sure.

Replacing my entire stealthburner with a dragonburner soon, will see if that helps.

54

After replacing my toolhead (new sherpa mini extruder and new dragon hf) the artifact is gone!
I may swap in my old dragon to see if it specifically was the problem, but replacing everything worked.

2 Likes
55

I would be happy if it really is the root cause of the issue!
Is/was there some play in the components or too much backlash in the old feeder?

56

I repeatedly tuned backlash in the Cw2 I was experiencing this issue with, didn’t see any change.

57

It seems that replacing the extruder would solve the problem, have you solved the problem now? Looking forward to your sharing

58

I had the same problem, is your problem solved now?

59

Hello @tomzz !

There is no reason to post the same question twice within 4 minutes.

For this read is not marked as solved, it obviously isn’t.

If you have an issue, please open a new thread with all requested information.