I just had an unfortunate mishap with my hardened nozzle, and now I need to replace it sooner than expected.

My plan was to keep using the hardened nozzle until INDX for the Core One L arrived. Well… that plan is gone, so since I have to buy a new nozzle anyway, I might as well consider going all‑in.

I mainly print PETG and ASA, but also a lot of PCCF, so I definitely need something abrasion‑resistant.

Is the Diamondback really worth paying twice as much as the E3D ObXidian? Should I invest in it now, or just grab an ObXidian and hope it lasts until INDX releases—at which point the Nextruder becomes obsolete anyway?

Also, what’s the actual difference between the High Flow and Standard Flow ObXidian nozzles? And why does Prusa sell its own ObXidian variant for a few euros less?

Wishing you all a great evening and a relaxing rest of the weekend.

I had some PLA break off just below the extruder gear. There is not enough to pull back out with pliers, and I have tried to heat the nozzle to 250C and push it through with a small allen wrench with no luck. Any other suggestions? Thanks!

I have followed the guide and tried different ways to solve this but I cant figure out how to do this properly.
https://help.prusa3d.com/article/adjusting-belt-tension-core-one-l-core-one_845048

The gantry alignment
Okay, so I have followed the steps outlined in the "Quick gantry alignment" section which seems to be another approach compared to what is described in the parent "Alignment" section: "Loosen the bolt on the corner with play less than the other." where i have loosened it completely as suggested in the quick version.

Anyway, I bent it into shape. I think... because its unclear how to test this. So far I have put the nextruder in the middle of the gantry and then gently pushed the gantry (pushing it as centered as possible) towards the tensioners looking for gaps. First I tried to make sure it was even by pushing the left side against the tensioner and a gap showed up on the other side. Doing the same thing on the right side caused a gap at the left side. Someone in the comments on the support/guide page had the same problem which then was advised by another commenter to tighten the belts somewhat. But I question that method because tightening the belts ever so slightly can possibly at this point have the undesired side effect that with the help of the belts straighten the gantry. The gantry is somewhat flimsy by design (nothing wrong here, just an observation) so I assume that some play is to be expected?

Keeping the gantry square
When it comes to the initial tightening of the belts to keep the gantry square, how should I know how much I have to tighten the bolts? There are no visible indicators. Should I just keep turning the bolts gradually and hope for the best? I've tried to use some reference guides in an attempt to make the tensioners equally loose and from that gradually tightening them as described. Problem is that the left one will become tighter sooner than the right one causing an uneven tension on the gantry. I've seen some people suggesting that you should then only continue with the right one so that the gantry is square and rely on the tuning later on.

Belt tension
Im using the "Belt tuning wizard" and I wonder how to accurately perform this test? If the top belt starts swinging at 88Hz I can keep it going up to 96Hz and at 96.5Hz it stops. Going backwards, from lets say 98Hz and down to 96Hz it will not start swinging until i reach a lower frequency, lets say 93Hz.
This made me stop the belt (by holding it still with a finger and then letting go) at each increment and let the belt start swinging by itself without the help of the previous frequency to find out the lowest and highest Hz. This narrowed the frequency range and somewhere in this range there will be a frequency that moves the belt the most...
But what to do when the belt moves about the same at lets say 92Hz as it does at 94Hz?
Am I doing something wrong here? What would the correct procedure be?

According to the guide "On CORE One L, the ideal target frequency range is a maximum of 95 Hz for the upper belt and a minimum of 85 Hz for the lower belt."
What does this mean? Anything between 85-95Hz is good enough for both belts?
Why then is the wizard so picky about some frequencies but not others? Sometimes it says "within range, nothing to do" and sometimes it wants me to adjust the tension even though both belts are within range? What am I missing?

For the core one 96Hz is optimal for the upper belt and for the lower belt it is 92Hz. There doesnt seem to be an equivalent for the Core One L.

Sorry for all the questions but I really want to understand this.

   I’m reaching out to the community for help regarding my Prusa Core One L. I have been working with Prusa Support for about 2 months now, but despite numerous attempts and tests, we haven't been able to find a definitive solution to the following issues:

1. Persistent Ghosting/Ringing: Highly visible on complex geometries and test models. It remains consistent regardless of software calibrations or mechanical adjustments.
2. Asymmetric "Clicking/Rattling" Noise: Originating from the rear-left motor block. The noise occurs during Front-Rear, Left-Right, and diagonal movements (Front/Left - Rear/Right). It is reproducible even when moving the print head manually with motors off. I’ve also noticed that the clicking volume increases as belt tension increases.

Printer Specs:

• Model: Core One L
• Firmware: 6.5.3 (issue also present on 6.5.2)
• Filaments used: Buddy 3D PLA Black and other PLA filaments (prusa and no prusa).

Steps taken so far (under support guidance):

• Software Calibration: Multiple Input Shaper and Phase Stepping calibrations performed.
• Belt Tension: Checked and set within nominal range (92 Hz Upper / 88 Hz Lower).
• Axis Maintenance: Cleaned and lubricated Y-axis rods with Prusa lubricant.
• Pulley Troubleshooting: Swapped the motor pulleys between X and Y motors. This makes the clicking disappear temporarily (for about 48h of printing), but then it systematically returns. Grub screws are correctly tightened on the flat part of the motor shaft.
• X-axis Guide Rail: Loosened the screws, pressed the rail down, and retightened them from the outside toward the center as suggested by support.
• Slicer Profiles: Tested both "Speed" and "Structural" profiles and change speed and acceleration; ghosting remains evident, especially on faster profiles.

Video evidence and documentation:

I have compiled several videos and test files that clearly show the noise and the print defects:

• Complete Analysis (Photos, Videos and G-codes): Analysis Archive
• Click sound video (google photo link): Click video
• Ghosting Test with Buddy 3D PLA Black - HF nozzle 0.4 - 0.25 lyaer height - speed profile

Has anyone else encountered similar issues with a Core One L? The fact that the noise returns shortly after reseating the pulleys makes me wonder if there's a defect in the motor itself or an internal bearing in the left block.

Any advice or insight would be greatly appreciated. Thanks!

Is this normal? I'm curious if this just means I need to tension the belts or maybe track down some other issue.

Crashed during a Print.

The support article is garbage. https://help.prusa3d.com/article/link-lost-35331-core-one-l_969549

I'm on my 4th roll now. None of the two first rolls could ram the filament so I could grab it after running out.

What am I doing wrong or should this not work?