Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App  

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Same for me, app stay at 0hz and web is too sensitive.

I use this : https://github.com/Diyshift/3D-Printer/tree/main/GT2%20Belt%20Tension%20Meter

I just build the thing with the spring, but i don't use the piano wire to "calibrate". I mesure the belt tension on my Bambulab, who have auto tension, with this tool and i found the number 2.3, so i use the same thing for the Core One and it work great.

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

You can also use this, a little less precise, but can help to start.

https://www.printables.com/model/46639-tension-meter-for-the-gt2-belts-of-i3-mk3s-or-prus/files

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Hello,
Thank you very much for the help.
This Belt Tension Meter seems to be a good start.

I will assemble one and test it out on my Core One.

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

I wanted to share a quick update and get some help with an ongoing issue I’m experiencing with my Core One (now about 2 weeks old).

What I’ve done so far:

• I calibrated the belt tension using the Prusa app on thier website.
• Both belts are showing frequencies of 84 Hz and 85 Hz, which seems spot on.
• I recalibrated Input Shaping using the accelerometer which completed successfully with results of 50 and 51.

The problem still persists:

• Since doing this, the printer’s auto-homing routine (the "headbanging" at the start of each print) is taking noticeably longer and occasionally failling.
• Every single print fails due to a layer shift, and it happens at different heights each time.
• I’ve tried multiple filaments (PETG-CF, PETG, and PLA), and the issue persists regardless of material.

It’s frustrating since the printer is still very new (2 weeks), and I’m unable to get any successful prints out of it right now.

Any advice or help on what to check next would be greatly appreciated.

Thanks in advance for your time and help!

Best regards,

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Here are a couple of photos to help visualize what i mean.

Best regards,

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

What filament are those printed from.  It looks like maybe you've got some underextrusion going on.  What filament profile are you using? 

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

The black parts are PETG-CF, and the petrol-colored part is PLA.

I use the standard non-HF profile, as mentioned in my original post.
The only part I changed on day one was the standard brass nozzle to a Diamondback one, since I knew I would primarily be printing with abrasive materials.

How do you determine if it's under-extruding?
Do you think this might be the cause of the layer shifting issue?
And if so, why is it only occurring in the second week and not from the start?

The parts i printed beginning of last week where immaculate, almost perfect with basicly no inperfections.

Otherwise, the printer is completely stock.
Non-HF profile.
Standard PETG-CF profile in PrusaSlicer.

Cheers,

RE:

Usually when your underextruding it happens during infill because that prints at a much higher speed than everything else.  And yes this can cause a layer shift because the nozzle crashes into the poorly printed areas 

Sorry I missed these points on your official post 

I'm still not sure which filament profile your using.

I once saw a review where they got clogging with their diamondback nozzles when printing cf or gf materials.  The inside of the diamondback nozzle is much rougher than a standard machined nozzle.  This was believed to be the cause.  I think they moved up to a .6.

That may not be your issue here as I haven't heard of any others with the issue. Normally increasing nozzle temperature by~10 degrees usually helps if it's underextruding. 

I'll try to find that video and post it if I find it. 

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Here was the video, I remembered slightly incorrectly, it was not complete clogging, but lower than expected flow rates.  

You might try the Prusament PCCF profile, or even maybe even reducing the volumetric flow rate to see if it improves things. 

Which brand of PCCF are you using? 

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Seitdem dauert die Auto-Homing-Routine des Druckers (das „Headbangen“ zu Beginn jedes Druckvorgangs) deutlich länger und schlägt gelegentlich fehl.

Have you tried the live chat or contacted support via email? 

I definitely recommend the live support.

The first thing I would check is the alignment of the X axis. 

To do this, push the X axle all the way forward. Now check whether both sides are against the stop or whether there is a gap on one side.

Jeder einzelne Druck scheitert an einer Schichtverschiebung und diese passiert jedes Mal auf unterschiedlichen Höhen.

I would first try it with the original nozzle and Pla to find the fault. 

The first thing I would do is check that the bed is correctly aligned.

To do this, first calibrate the z axis in the menu.

The bed moves all the way down and is then leveled.

Now do an Autohome and then set the Z axis to 1mm.

Switch off the motors in the menu. 

Now move the print head in the entire print area and pay attention to the distance between the nozzle and the bed.

Are there any deviations?

Check whether the screws of the motor pullys are tight.

Are the knurled screws of the hotend tight?

Is the hotend pushed all the way up?

Do you have the opportunity to record the print with a camera? 

Then it might be easier to see when or why the shifting occurs.

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Thank you again for your helpful tips! I’ve been doing some further testing and wanted to share my latest findings with you.

First, I don’t have the camera for my printer yet, but I’m hoping the Buddy camera for the Core will arrive soon so I can start sharing videos.

Regarding the X-axis squareness, I noticed that the belt frequencies don’t match up at 85 Hz. When I square the frame by adjusting it at the front, the left belt sits around 87 Hz, while the right one is at 95-96 Hz. If I set both belts to 85 Hz, there’s about a 0.5 mm gap on the right side of the Print head arm?.

I haven’t tried reducing the flowrate yet, but I plan to do that next.
I will also do the recalibration of the Z-axis, which might help improve things a bit.

Posted by: @brian-12

Which brand of PCCF are you using? 

I don’t use PCCF. I use Prusament PETG-CF (Black, 1kg). I’m currently using the standard profile in PrusaSlicer.

I’ve included a screenshot of my filament settings below for reference.

About the Layer Shifting Issue:

During testing, I found something interesting: enabling the "Don’t allow crossing of perimeters" setting made things worse. When I printed a more complex part with this option enabled, the printer moved erratically, often resulting in a layer shift within the first 10 layers. The sound during the shift is a sharp "crack," and when I stopped the print, I noticed that my belt tension had dropped from 84-85 Hz to around 80-82 Hz.

I’m not sure if the layer shifts are causing the belts to loosen or if the belts are over-stretching and causing the issues. My next step is to try holding the screws in place during the shift to see if the belts loosen again afterward, or if this is a tension system problem.

Disabling the "Don’t allow crossing of perimeters" setting does seem to improve the layer shift problem significantly, but I’d never had it enabled before—I only discovered it by accident.

Thanks again for your support, and I’ll keep you updated on my next tries.

Best regards,

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Posted by: @rainer-2

Have you tried the live chat or contacted support via email? 

___________________________________________

I reached out to Prusa support again, and the helpful woman recommended that I contact thier live support for the best results.
I’ll be contacting them this Friday after work, so hopefully, we can find a solution together.

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

Any additional updates? I'm having the same issue with layer shifting using Prusament PETG Orange (also trying to print the drybox). I was able to solve for some stringing by adjusting the multiplier down a bit and increasing temps a bit after the first layer, but there are some small layer shifts that are still happening. Initially when i got the printer it wouldn't work due to the belt tension - I had the same problems using the tuner and getting reasonable results. They were all over the place. I'll try the belt tension tool above, but since its 3D printed im not sure how accurate it will be as this is my only printer.

RE: Belt Tension Issues on New Core One – Layer Shifting & Unreliable Tuner App

I have an update and found the culprit.

After disabling the setting that prevents the toolhead from crossing perimeters and the setting to print outside first, the errors magically disappeared. It's a bit strange since I haven't touched the belts at all. (Left 85 Hz, right 83 Hz; X-Y gantry is not square).

I hope this can help others. Prints come out very clean and precise with some PETG-CF now.

Cheers 🙂