What can I do against the moire effect?



  • My printer is an Ender 3 with the Hemera and I'm printing with 32x microstepping except the e axis which is set at 16x. What could be causing this artifact: https://imgur.com/a/s2qAibN?s=wa





  • What controller? If Duet 2 wifi ethernet try 16x with interpolation to 256.



  • ...just to clarify interpolation to 256 only works on 16x for the Duet 2 ethernet/wifi/Maestro . It works for any microstep setting on Duet3.



  • @DocTrucker Duet Maestro and I think I have interpolation enabled



  • @DocTrucker Oh okay. I didn't know that. So should I set all my motors back to 16x for better quallity?



  • @maroonds I'm not 100% certain on Maestro, but that is the case for the wifi and ethernet. Worth a shot.



  • My bad.

    "The Duet 2 Maestro supports interpolation at all microstep settings."

    https://duet3d.dozuki.com/Wiki/Gcode#Section_M350_Set_microstepping_mode



  • Looks like you're running 1.8 steppers. What voltage are you using on VIN? Got current set to at least 80% of rated current? Have you got 0.9 degree steppers handy to try?

    It would be worth trying to fing out if it is coming from the xy steppers or extruder stepper by changing layer thickness and keeping an eye on frequency.



  • ...there's an outside chance TL-Smoothers may help. Would be cheaper to try them before 0.9 steppers but I don't think Duets suffer the same issues that were cured on other boards by TL Smoothers.



  • @DocTrucker I unfortunately only got pancake 0.9 degree steppers but I think I've set my motor currents correctly



  • Try increasing or decreasing the layer thickness by 20% and seeing if the frequency of the pattern changes.



  • Okay, thanks. I'll start printing now. I've also figured out that my motor currents were a bit too low.


  • administrators

    @DocTrucker said in What can I do against the moire effect?:

    ...there's an outside chance TL-Smoothers may help. Would be cheaper to try them before 0.9 steppers but I don't think Duets suffer the same issues that were cured on other boards by TL Smoothers.

    Unlikely that TL smoothers will help on a Maestro. OTOH, I think the Ender extruder has low steps/mm (about 100 AFAIR), so setting extruder microstepping to x64 may help.

    EDIT: and yes, higher motor current will help as long as you don't overheat the stepper motor.


  • Moderator

    @maroonds said in What can I do against the moire effect?:

    Ender 3 with the Hemera

    I'd check your assembly of the Hemera since it seems like a repeating pattern. Are your gears meshing smoothly?



  • I hope you figure it out, I have a delta which is prone to this anyways, but I was clear of it initially when I moved from a PG35L stepper in an UMBEE setup, and it appeared when I started using a direct drive E3D titan (tried two difference 0.9 deg steppers). I've minimized how significant it appears, but it drives me crazy showing up most notably in shiny filaments (as in silk types). I replaced the gears/hobb/idler/stepper (and calibrated the driver)/ face plate, and even redid the feeds so I can print ninjaflex easily. As far as I can tell this appearance of this artifact is due to any less than perfect eccentricities/offsets in the gear system. I also tried tl-smoothers for shits and giggles to no avail.

    So if anything isn't perfectly in plane/ perpendicular, you'll have this to a degree equal to the amount whatever components are out of perfect alignment.

    I truly hope you figure it out with a simple solution so you can post the solution and I can replicate it. I wish you the best of luck.



  • I finally cleared this up on my E3d titan, had moire patterns like the second picture first post. I eliminated the software/ electronics ( changed stepper driver settings, each value individually although it was on the fly during 10mm test towers, and even purposely bad ones), motor current, microstepping high and low, thegolden ratio layer heights, extrusion/flow rate,slicers, motor cables. It confirmed what I suspected in my case which was that it was hardware and top of the list was the titan itself.

    I don’t know what fixed it specifically since at that point I wasn’t doing that many disassemblies. I reprinted the motor mount and sanded to try to keep things perpendicular. I drilled out the the old titan cover plate and added a copper sleeve to the motor shaft intending to constrain shift alignment and any deflection from the tensioner. I had lots of spare parts since I swapped everything on the titan but the main body. When arranging the gears, I adjusted the delrin gear on the hobb so the tensioner arm was as close to perfect feeding filament into the center of the hobb. When I was doing that I noticed the both delrin gears had slight issues, one didn't sit perpendicular on the hobb when looked at with an engineer square ( I used it a on anything I could to see who my culprits could be for not being perpendicular when they should) and the other was not truly flat when viewed against the straight edge. Fixed one up and put it in and noticed when I was trying to get the gears flush to a razors edge (literally) that the hobb gear wobbles weird in it's bearing. So I swapped out the hobb's bearing in the body of the titan, (the one in the cover was checked too). I also added so kapton tape where the v6 mounts into so there is zero play even with effort. I finished putting it back together and one or a combination of things fixed it. Going to a hemera was my next move if I didn't get rid of it here, if only for the on motor mount points for my probe and and flex filament performance.

    My gut says based on the pattern, it was likely the fact that the gears were not perfectly in line (seriously, I couldn't tell other than the bearing until I got out my good square) and wobbling during rotation either due to the motor shaft not being perpendicular for the metal gear, the delrin gear not being truly flat / crooked on the hobb, or less than stable bearing the hobb gear rode in. With the hemera you have a few parts you out together that could be the source, and it makes it even harder to identify since a few critical ones are small and short so perpendicularity of shaft to gear and round and centered of the rotating parts will Tedious. Still you could get by simply with A printed jig and dial indicator along with some squinting at the part on a engineer / machinist square or at least straight edge in front of a light. .


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