RE:
MK4 doesn't need to do any of that. Straight line is just moving one motor in one direction. Easy.
You can try rotating your parts 45 degrees in slicer and you'll notice less ripple on the core one. (for an example, printing a box).
That's what I thought initially. But the typical observation for printing surfaces oriented at 45° in a CoreXY seems to be that the pitch of the VFA changes? From 2 mm to 1 or 1.41 mm -- reports vary, and I'm hitting the limits of my spatial imagination to determine what I would expect when only one motor and belt moves...
Do the bedslingers show VFAs (or belt ripple) when printing parts oriented at 45°? They would have the same challenge of keeping two motors and belts exactly in sync then.
Edit: Sorry, I can't figure out why part of the quote above is set in bold, and can't turn that off. No emphasis or other subtext intended from my end.
RE: VFA Artifacts on X+Y Straight Edges
Here we go => https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.3.1
No mention of phase stepping and no mention of anything related to the nozzle cleaning failed issue. 😯
RE: VFA Artifacts on X+Y Straight Edges
Presumably they want us to get the other fixes and things now while they continue to work on the out of memory error or whatever... I guess this is better than nothing. Maybe they will release a 6.3.2 alpha in a short time?
I wonder if the automatic filament retraction would address some of the cleaning issue by having less filament at the nozzle to upset the bed taps.
Here we go => https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.3.1
No mention of phase stepping and no mention of anything related to the nozzle cleaning failed issue. 😯
RE: VFA Artifacts on X+Y Straight Edges
I just loaded a filament and launched a print in PLA with this firmware.
Automatic filament retraction
We’ve introduced automatic filament retraction at the end of a print, with reinsertion just before the first extrusion. This brings several benefits:No filament remains in the nozzle during mesh bed leveling, helping prevent filament specs from being left on the print bed.The nozzle no longer needs to be heated for filament unload.
Note: This is a pilot implementation of the procedure. If it proves effective, we plan to extend it to other printers as well.
One word: Finally!
I never understood why they never ported the same ramming procedure from the MMU3 that leaves the nozzle perfectly clear even when using a filament which is prone to oozing.
Just one note, at the start of the intro line I got some skipping noise from the Nextruder, I guess the retracted filament doesn't had the time to warm-up. But it is already a very good thing.
Also now we have a popup message to don't miss to open/close the air intake from the top panel. I personally felt into this kind of issue, but I am not sure about the necessity to acknowledge this popup (one more click). But if it disappears after a while, we still can miss it...
RE: VFA Artifacts on X+Y Straight Edges
but I am not sure about the necessity to acknowledge this popup (one more click). But if it disappears after a while, we still can miss it...
Ok I said bullshit, they are smarter than me. 😆
Note: This prompt is shown only once and is skipped for consecutive prints with the same configuration.
RE: VFA Artifacts on X+Y Straight Edges
Why doesn't anyone compile the firmware with this item in menu enabled?
All is needed is to revert the revert commit, compile firmware and flash onto printer. And you don't void warranty this way.
It doesn't seem that PS calibration didn't work, but was somewhat unstable.
RE: VFA Artifacts on X+Y Straight Edges
Why doesn't anyone compile the firmware with this item in menu enabled?
All is needed is to revert the revert commit, compile firmware and flash onto printer.
Because people don't have the required toolchain installed?
Because people don't know how to use github, revert commits etc.?
Because people assume that there might be a good reason for Prusa not to release this?
Because people think it should be Prusa's job to fix the problems in their $1000 printer, not the customer's?
Just some ideas... 🙄
RE: VFA Artifacts on X+Y Straight Edges
My apologies, I didn't mean my question as an attack nor a solution for issue, but something that would give us an insight whether phase stepping calibration really solves the VFAs.
BTW, I compiled the firmware, no weird stuff in there, just one reverted commit, I prommie, and of course I provide it as is and only you are responsible for your printer and what you flash it with.
RE: VFA Artifacts on X+Y Straight Edges
Update from Prusa development lead, danopermis, on Github:
Yes, that is correct, we had to disable the calibration in the menu for the final build. It fails too often and we didn't want to deal with all the bug reports due to BSOD caused by OOM situation.
If you are running 6.3.1 and you still want to try it, you can issue M1977 G-Code via serial line or by "printing" a file containing just this line. This should run the wizard. That being said, please understand that this is still experimental and may fail in unexpected ways. If it fails, you should be able to recover by doing full factory reset.
We are in a weird spot here, where we would like to gather more feedback from the community, yet this feature may actually harm the printer's performance. I sincerely hope that github users would understand this delicate situation.
https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/4461
@john-doe-29: No offense taken! 👍
RE: VFA Artifacts on X+Y Straight Edges
Oof, I was totally on board until "full factory reset" 😀 So could be a bit more of a pain to test this and then have to re-set everything up. Still nice for the option to be granted.
Update from Prusa development lead, danopermis, on Github:
Yes, that is correct, we had to disable the calibration in the menu for the final build. It fails too often and we didn't want to deal with all the bug reports due to BSOD caused by OOM situation.
If you are running 6.3.1 and you still want to try it, you can issue M1977 G-Code via serial line or by "printing" a file containing just this line. This should run the wizard. That being said, please understand that this is still experimental and may fail in unexpected ways. If it fails, you should be able to recover by doing full factory reset.
We are in a weird spot here, where we would like to gather more feedback from the community, yet this feature may actually harm the printer's performance. I sincerely hope that github users would understand this delicate situation.
https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/4461
@john-doe-29: No offense taken! 👍
RE: VFA Artifacts on X+Y Straight Edges
Hmm, I'm tempted to try it... Does anybody know how to generate a .bgcode file with the required gcode?
RE: VFA Artifacts on X+Y Straight Edges
Most recent discussions on the Github issue are not promising regarding phase stepping calibration with the current firmware; reports of repeated crashes from the first "inofficial" attempts by users. But there's hope that the Prusa team will get a robust version out eventually:
We are on the edge of the hardware capabilities, we have some optimuzations ready, please stay tuned.
RE: VFA Artifacts on X+Y Straight Edges
You don’t need bgcode, just a text file with one line that says “M1977” and name the file with the “.gcode” extension.
I’ve run it five times now with no memory error, but it always concludes with “Calibration failed to find corrections to motor current” even though I can hear the harmonics myself.
Now I’m trying different heat block angles in case that might generate better data. There’s a line in the calibration code that makes me think a 45 degree angle might be better, but I haven’t had luck so far.
RE: VFA Artifacts on X+Y Straight Edges
I also switched the nozzle from ObXidian HF to the stock brass HF, since the ObXidian doesn’t allow the accelerometer mount to seat perfectly.
And I ran the input shaper calibration, saved the new settings, and ran the phase stepping calibration again.
Same message every time and no OOM error.
RE: VFA Artifacts on X+Y Straight Edges
I’ve run it five times now with no memory error, but it always concludes with “Calibration failed to find corrections to motor current” even though I can hear the harmonics myself.
Does the audible noise level change during the calibration? I remember reading descriptions of the process on the XL (or seeing videos too?) where it became gradually quieter during the optimization/calibration run.
RE: VFA Artifacts on X+Y Straight Edges
On my machine it’s not a monotonic function; some phases are loud and others are quiet, but it doesn’t just keep getting quieter.
I’ve run it five times now with no memory error, but it always concludes with “Calibration failed to find corrections to motor current” even though I can hear the harmonics myself.
Does the audible noise level change during the calibration? I remember reading descriptions of the process on the XL (or seeing videos too?) where it became gradually quieter during the optimization/calibration run.
RE: VFA Artifacts on X+Y Straight Edges
On my machine it’s not a monotonic function; some phases are loud and others are quiet, but it doesn’t just keep getting quieter.
Maybe that's already a sign that it's not converging, eventually resulting in the error message?
The most recent Github post from danopernis suggests that they have not given up on this and expect to follow up with a robust implementation soon. Fingers crossed!
RE: VFA Artifacts on X+Y Straight Edges
If I remember correctly, that's exactly how it should work. Different speeds/acceleration result in resonances which are sometimes louder and sometimes quieter. It's not a linear process since it also depends on your environment where the printer I'd located.
On my machine it’s not a monotonic function; some phases are loud and others are quiet, but it doesn’t just keep getting quieter.
Maybe that's already a sign that it's not converging, eventually resulting in the error message?
The most recent Github post from danopernis suggests that they have not given up on this and expect to follow up with a robust implementation soon. Fingers crossed!
RE: VFA Artifacts on X+Y Straight Edges
Maybe that's already a sign that it's not converging, eventually resulting in the error message?
Yeah, I think that’s the case.
My next plan is to take the upper chassis and panels off and check mechanics. I know the gantry is off kilter, so that’s the first thing I’ll tackle. Depending on what I find, I may try to figure out how to make the gantry brackets more rigid. I suspect those brackets are a culprit.
IIRC someone here swapped the smooth belt idlers for toothed. Did that help at all?
RE: VFA Artifacts on X+Y Straight Edges
I think we may just see some longitudinal oscillations in the (long) belts, excited by not-so-smooth motor stepping. In which case the only way to reduce the effect would be to excite those vibrations less, by making the motors run more smoothly.
My educated guess is that "calibrated phase stepping" modifies the timing or current distribution of the motors' microsteps to ensure smooth operation. Not required with "perfect" motor specimens, which might explain why e.g. the invited Youtube reviews typically did not mention VFA problems. But helpful to compensate for asymmetries in the motors which cause non-equidistant microsteps.
I have not found any technical documentation on what Prusa calls "phase stepping", and a superficial look at the source code was not enough to confirm what it does. Has anyone already dived deeper?