RE: Ringing/ Ghosting pattern all over my prints :/
I have the exact same issue. Prusa support sent me a lube kit and I've completed lubing all axii linear bearings, and still have the issue. It's the worst on the front-facing X-axis. I've messed with the flow rate, temps, belt tension (with the app) etc etc. I've got a cold and trying to figure this out, so I'm long-past hoping for a silver bullet here.
I'll replace the idlers if I have to, but I'd rather not.
It doesn't help the filament they ship with the printer seems to hide this pattern a lot. Any shiny filaments and it shows up like a bad penny.
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I also had the same VFA problems on my multi-tool XL. I have not completely eliminated it, but was able to minimize it by:
- Make sure the belts on the rear of the XL are not rubbing on the dock cable routers that are used to keep the toolheads parked. On mine, the top of each dock cable router was slightly cantered towards the rear of the printer. It caused the top locknut that sticks out of the dock cable routers to ever so slightly rub on the belt. And if I deliberately push on the belt in the rear, I can physically see the gantry shift in the Y direction. Even some subtle rubbing on the heads of the locknuts can lead to mild shifting in the Y direction. I followed advice on another thread, and wiggled each dock cable router towards the front and rear while tightening the Torx bolt to properly align and secure it to the silver metal plate inside the rear aluminum channel.
- Make sure the left/right sides of the X gantry are aligned. When the gantry is pushed the whole way to the front, there should be no gap on the left & right. The gap can be closed by slightly tightening the belt idler on the side with the gap.
- Check & correct the belt tension. I did it with a combination of the Prusa app which listens for the frequency of the belt and the MK3S belt tension gauge. The sweet spot on the MK3S gauge is when the arrow is just above the MIN marking on the gauge. Mine were too tight. I will be ordering a more accurate belt gauge in the future as I prefer a direct reading vs using the Prusa app that just listens for the correct frequency. I believe a belt that is too tight causes the belt teeth to compress more on the 2 smooth idler pulleys on the X axis. Note, that steps 2 & 3 are iterative. You may have to go back and forth a few times to find the sweet spot.
- Don't use stealth mode. I believe the slower print speed is causing some type of resonance to dominate when in stealth mode. At first I thought the input shaper was calibrating differently depending on whether stealth was enabled or not. However, I went through all 4 combinations of stealth & input shaper calibration, and the dominant factor was stealth mode.
With the above changes, the VFAs are almost completely eliminated. To improve further, at some point in the future, i will also replace the two X axis idler pulleys that are smooth with a toothed version (Gates 6mm, toothed, bore diameter=3mm) (Example: https://www.filastruder.com/products/gates-2gt-idler?_pos=1&_sid=1d42bf29e&_ss=r&variant=15443755728967)
RE: Ringing/ Ghosting pattern all over my prints :/
<Reposting pic of test print since it didn't take in the last post.>
This is a test print with improvements 1-3 from my previous post applied. The bottom 2/3 of the print is with stealth off and the top 1/3 is with stealth on. The VFAs are evident in the middle of the print on the top 1/3. There is some subtly evidence of VFAs on the bottom 1/3 (where stealth is off). But it's a big improvement compared to before the tuning was done.
RE: Ringing/ Ghosting pattern all over my prints :/
Wondering if anyone has noticed that the top belt (right motor) seems to "ride up" as the gantry moves to the front of the rails? I swapped belts as I had tension way too high previously, and combined with ~3800 hours on them, they were getting chewed up. After replacing with new belts (from prusa) and noticed that I'm getting a lot more of this artifacting now and wonder if its related. Can't really tell why it might be happening, almost looks like the tensioner on the right side is too high or tilted or something so it pulls up the belt as it moves forward.
Adjusting tensions down a bit helped, but the pattern is definitely the 2mm belt. I keep seeing old/new o-ring mentions. I have the old ones based on manufacture date, but how are the 'new' ones different and what are they supposed to fix?
This all started because I noticed it was printing out of square (enough to cause a 0.30mm difference over a 200mm square). Adjusting the tension so the gantry is flat with the front results in out of square. On suggestion from prusa, adjusted tensions to leave a gap on one side, for me this wound up being about 11 thou (.28mm) gap on the left side to print an even 250mm diagonally.
RE: Ringing/ Ghosting pattern all over my prints :/
Any updates on this?
I’m printing PETG in vase mode with a 0.8 nozzle and experiencing the same issue.
Here’s what I’ve tried so far:
• Reprinted all the CoreXY belt tensioning parts with better tolerances.
• Re-squared the gantry—don’t ask how, it’s very random. The alignment changes every time you reassemble it.
• Swapped spacers with 1.25 and 1.5mm O-rings (FYI, Prusa uses 1.25mm).
• Adjusted belt tension between 70–120 Hz, with both aligned and misaligned gantries.
• Played with the phase stepping bug (changing print speed mid-print allows recalibration at non-default speeds). Tried 75% and 85%—no noticeable difference.
• Tweaked speed (20–75 mm/s), layer height, cooling, jerk, extruder jerk, and acceleration. Slight improvement in non-vibrating speed ranges (20–35 mm/s). VFAs only appear on the back wall.
• Swapped idlers, tried toothed ones, different brands, and new stepper pulleys—no real change.
• Bought new steppers (Prusa changed manufacturer—new ones have different bolts and shafts)—very slight improvement.
• Added stepper dampers using O-rings—no difference.
At this point, I suspect it might be something wrong with how the steppers process signals—maybe something on the motherboard side? I’m not great with electronics, so I can’t say for sure.
Right now, I’m out of ideas. My Bambu printers just work—and after some tuning, they produce perfect vase mode prints. Meanwhile, the Prusa feels like an expensive paperweight.
RE: Ringing/ Ghosting pattern all over my prints :/
The problem with the 2mm pattern also seems to occur with the new Core One printer. https://forum.prusa3d.com/forum/prusa-core-one-hardware-firmware-and-software-help/vfa-artifacts-on-xy-straight-edges/
Unfortunately, no solution there yet either.
I have now tested four different belts. Various idlers and pulleys. Replacement of the stepper motors. Realignment of the mechanics. Loosening and tightening all the screws. With and without phase stepping or stealth mode. Nothing really helps. After resetting the Prusa XL to its original state, the results at 50mm/s outer perimeter print speed were suddenly better again. Not perfect, but usable. However, the cause of the VFAs still remains a mystery.
At the beginning I had better results with toothed idlers. At the end with smooth idlers. This printer drives me crazy.
The only thing I found out, that less belt tension helps most for better results with my printer. So I am printing with 75 Hz (Prusa belt tuner) at the moment. Not a satisfying result for an engineer. I could really need some help.
RE: Ringing/ Ghosting pattern all over my prints :/
I put in a GitHub request awhile back for this issue, but it went largely ignored and was eventually closed.
In my case the MK4 has near flawless prints, no VFA'S and I expected the same on the XL, but it's just not. I don't know if it's the 1.8° steppers vs. the .9° steppers, but it's definitely not as good. Now the VFA's on the XL aren't terrible, but just not as good as the MK4 and I just expected being a premium machine that it would be as good or better.
I also replaced the smooth idlers with toothed ones but it made no difference. I feel there is some root cause tuning issue.
RE: Ringing/ Ghosting pattern all over my prints :/
After 1.5 months of tinkering I contacted support because of the same issue in XL.
I Think there are two possibilities - too weak frame - you can see that the idlers in the back will never be perfectly perpendicular to the floor, always axes are a little bit skewed and it is impossible to align belt.
Second possibility - stepper control - I changed steppers to newer ones from Prusa shop, and it caused a slightly improvement, but still there might be a problem with controlling the steppers.
I put in a GitHub request awhile back for this issue, but it went largely ignored and was eventually closed.
In my case the MK4 has near flawless prints, no VFA'S and I expected the same on the XL, but it's just not. I don't know if it's the 1.8° steppers vs. the .9° steppers, but it's definitely not as good. Now the VFA's on the XL aren't terrible, but just not as good as the MK4 and I just expected being a premium machine that it would be as good or better.
I also replaced the smooth idlers with toothed ones but it made no difference. I feel there is some root cause tuning issue.
RE: Ringing/ Ghosting pattern all over my prints :/
I‘m also experiencing this issue on my brand new XL. Nothing I’ve tried seems to make any difference at all.
I’ve spent ~2 months going back and forth with support and haven’t managed to get anywhere.
RE: Ringing/ Ghosting pattern all over my prints :/
Have you tried to refund? I asked for 75% refund (will be ok to buy H2D), and never buy anything from that funny Czech brand again.
I’m really angry that bambu decided to not launch preorder for H2D, because it was the only reason why I bought this expensive paperweight made by Czech students.
I‘m also experiencing this issue on my brand new XL. Nothing I’ve tried seems to make any difference at all.
I’ve spent ~2 months going back and forth with support and haven’t managed to get anywhere.
RE: Ringing/ Ghosting pattern all over my prints :/
Prusa is now sending me replacement XY motors and pulleys. I have previously already replaced the belts. If the problem isn’t solved by swapping those parts out, I’ll likely be inquiring about my options.
This machine has been a welcome improvement to my setup in many ways, but the surface quality of printed parts is very disappointing. If I could get it to produce parts as clean as my MK4, I’d be thrilled.
Have you tried to refund? I asked for 75% refund (will be ok to buy H2D), and never buy anything from that funny Czech brand again.
I’m really angry that bambu decided to not launch preorder for H2D, because it was the only reason why I bought this expensive paperweight made by Czech students.I‘m also experiencing this issue on my brand new XL. Nothing I’ve tried seems to make any difference at all.
I’ve spent ~2 months going back and forth with support and haven’t managed to get anywhere.
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Nice, today they also told me that I need to replace belts. But because I bought the printer from certified reseller, I need to talk again about everything to the reseller to get new belts worth 20 euro xD. And I know that will not work, because it is a nonsense that a belt can be faulty on all the length, also when rotated 180*. I HATE PRUSA
Prusa is now sending me replacement XY motors and pulleys. I have previously already replaced the belts. If the problem isn’t solved by swapping those parts out, I’ll likely be inquiring about my options.
This machine has been a welcome improvement to my setup in many ways, but the surface quality of printed parts is very disappointing. If I could get it to produce parts as clean as my MK4, I’d be thrilled.
Have you tried to refund? I asked for 75% refund (will be ok to buy H2D), and never buy anything from that funny Czech brand again.
I’m really angry that bambu decided to not launch preorder for H2D, because it was the only reason why I bought this expensive paperweight made by Czech students.I‘m also experiencing this issue on my brand new XL. Nothing I’ve tried seems to make any difference at all.
I’ve spent ~2 months going back and forth with support and haven’t managed to get anywhere.
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I am unsure why my reply here got moderated off, but I was facing the same issue, the screws that hold the toolhead mounts, allen-key through the back of the hexagon mesh and tighten them. The instructions are on YouTube. If you can see the belts, the lock nuts on the back of each dock may be rubbing against the belt, and also check the position of zip tie heads. If they are facing out, they may also be rubbing against the belt.
You should have about 1.5mm of spacing between the lock nuts and the belt. When you grab the dock and move it back and forth a bit, it shouldn't touch the belt. That's how you know you've tightened it enough. One photo is the prior result before tightening the docks. The other is starting at stock structural profile, then every few layers increasing the "speed" using the encoder on the front of the printer. Turned the dial all the way to 800%. I know that's not "real 800% speed" but it's impressive nonetheless. At about 300% any VFAs disappear and I get silky smooth surfaces on all sides. The corner bulge can be tuned out.
RE: Ringing/ Ghosting pattern all over my prints :/
Quick update on my troubleshooting journey:
I got the replacement parts from Prusa, and while checking the motors, one had very distinct, well-defined steps when turning the shaft by hand. The other felt much smoother, with less pronounced detents. Prusa’s sending out another motor to replace that one.
I’ll post another update once I’ve tested the new parts or if anything else changes along the way.
RE: Ringing/ Ghosting pattern all over my prints :/
I got a similar Problem on roundings which i solved by exporting an new stl file with customized Settings to be much more than just Fine in Onshape could reproduce this ob my Prusa as well as on my Bambu
RE: Ringing/ Ghosting pattern all over my prints :/
Here’s a cleaner and slightly more polished version that keeps your tone and structure, while tightening things up:
Another update on my troubleshooting with Prusa:
I’ve just finished installing the replacement XY motors that Prusa sent, along with new motor pulleys and tensioner pulleys.
Unfortunately, there’s been no noticeable improvement after swapping out these parts.
I did notice that one of the replacement motor pulleys isn’t concentric. There’s a slight wobble as the motor shaft rotates.
I’ve gone ahead and requested that Prusa accept the printer for repair so we can dig deeper into the issue. At this point, I’m just waiting for that process to get started.
I’ll share another update once I hear back.
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Whoops, I left in the ChatGPT assist. Not great at articulating my thoughts, so forgive me lol
Here’s a cleaner and slightly more polished version that keeps your tone and structure, while tightening things up:
Another update on my troubleshooting with Prusa:
I’ve just finished installing the replacement XY motors that Prusa sent, along with new motor pulleys and tensioner pulleys.
Unfortunately, there’s been no noticeable improvement after swapping out these parts.
I did notice that one of the replacement motor pulleys isn’t concentric. There’s a slight wobble as the motor shaft rotates.
I’ve gone ahead and requested that Prusa accept the printer for repair so we can dig deeper into the issue. At this point, I’m just waiting for that process to get started.
I’ll share another update once I hear back.
RE: Ringing/ Ghosting pattern all over my prints :/
Thanks for keeping us up to date on this.
RE: Ringing/ Ghosting pattern all over my prints :/
Are your slide rails well greased?If my printer gets loud, I know I need to regrease it.Then there will be hardly any vibrations on the frame.I also have the XL frame on a concrete slab, which I've cushioned with a rubber washing machine mat.
RE: Ringing/ Ghosting pattern all over my prints :/
Greasing the linear guides makes the printer quieter, but does not help to reduce the VFAs.Replacing the belts doesn't really help either.I have also tested various pulley models without success.
During my research I came across an interesting website. https://prorifi3d.com/pages/technical-details The VFA problem seems to be a fairly old problem in 3D printing. After many attempts, my observations match prorifi3d's theory. The main cause is most likely the motor resonances and an irregular force distribution of the stepper motors. Since the VFAs change with the motor speed, it may help to optimize the speed of the outer lines. However, this only helps to a limited extent with a printer like the XL, because depending on the printing angle, one motor turns faster and one slower, and the VFAs reappear. I have just ordered a replacement motor from Prusa for further testing. This now appears to be a new model. It is significantly quieter, but also produces VFAs, albeit with a different resonance behavior than the old motor. The Orca-Slicer VFA test shows a clearly different pattern with the other motor model, but unfortunately not optimal results either. I'm now pretty sure where I need to look for a solution. However, motor optimization should be a big challenge.
Maybe also interesting for further ideas to minimize the VFAs: https://www.automate.org/motion-control/tech-papers/solutions-to-reduce-stepper-motor-resonance
I'll try to print the motor mounts out of hard TPU. Maybe that will help to reduce the resonances.