Belt tension matters!

Hey guys!

Dont underestimate belt tension.
I just recently somewhat tuned my Vcore3 and wanted to show how much difference ONLY belt tensioning makes. I lost my Y shaper results, but I think this still not perfect X comparison speaks for itself.

Shaper before

Shaper after


I don’t know how to read these graphs. Maybe you can tell us more about this?

First a background.
Since we are dealing with corexy, where a pair of motors operate the toolhead, It is really important to get the belt tension correct AND equal on both motors.
Input shaping uses clever algorithms to alter motion in real time, thus negate unwanted frequencies and reducing ringing/ghosting.

In this link you can read more on how to equal belt tension with the help of automated scripts.
Measuring Resonances

The graphs I embedded are a function of frequencies during input shaping and their respective amplitudes. In other words “how much the toolhead shakes at each frequency”
There are multiple input shaper algorithms such as ZV, MZV, EI…
Each use different frequency and amplitude range to try and negate vibrations.
You can say, that the more aggressive the shaper, the more smoothing you get at edges, decreasing dimensional accuracy.

You can see in the graphs, that before I had two separate frequency spikes, thus input shaping algorithm recommended 2HUMP_EI at 97Hz negating both spikes at @60Hz and @130Hz at the cost of higher smoothing and lower accelerations.

Once I equalled the belt tensions the spike at @130Hz hugely dropped in amplitude and shaper recommends MZV @69Hz with 0 vibrations, higher accelerations and reduced smoothing

In conclusion. Klipper is awesome :smile:


Would you have any idea how to tighten the belts on an Ender 6?

Do you use stock Marlin firmware, or have you upgraded to Klipper?

I am currently running Klipper

Are you asking how to actually tighten the belts (what screws to turn) or you are asking about the process of fine tuning the tension?

Which screws I tighten.

There are some screws in the back, next to the motors which can be loosened or tightened, according to your needs.

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Would you know how to read this graph? I ran the testing custom axes script from the Klipper docs and got these results, and I don’t know how to read the graph.

Man, sorry to get to you so late. I was off and wasnt checking forum at all.
This is Ender 6, right? The Blue graph shows a motor that moves your carriage from back left to front right. and the orange moves from back right to front left.

Your graph shows that one belt is tighter than the other. I really have no idea how the belts on Ender 6 tension tho, so I cant help you with that, sadly :confused:


Awesome. Thanks man. I’ll see which one it is and tighten them. Thank you again.

Would improper belt tension be the cause of loud almost grinding noises at higher print speeds? I’ve been going back and forth with Comgrow regarding the issue and they have no solution. Well I take that back, their solution is to print at 60 mm/s max. LOL

You are expecting to get support for a modified printer. In this case, Comgrow cannot provide support.
It’s the same thing as modifying a car to be a race car, and wondering why you can’t get it serviced in warranty :slight_smile: