Bambu Lab should adapt the X-Gantry accordingly. There is clearly a noticeable leap in quality.
Iâm afraid they doesnât care.
I mailed them about our finding, explaining what we have done and showing before/after pictures.
With a link to this thread.
They just answer me to change my belt⊠without even reading my mail.
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I was not aware of how much this also effects the small prints. Recently reprinted a chassis for a 1:24 scale rc (losi micro platform) I made. It has a <20mm flat surface on x-axis and around 4-5 times of that length, oriented parallel to the y-axis. I had printed the same model 2 years ago on my ender 3 v2. I was shocked to see the wavy pattern on x-axis, only on the bambu, which must be highlighted bc of the black, shiny petg I used but stillâŠ
Iâve always suspected it was something to do with either the belts or pulleys as it is perfectly correlated to the 2mm belt pitch. I also suspect having high quality pulleys and belts also makes a big difference for someone upgrading so I wouldnât skimp out. Any chance we can see a VFA test in black PETG printed at 285c at different speeds?
Iâve found you can speed up prints to help reduce, however your layer adhesion suffers significantly. If I turn up temps to 285c for PETG at standard speeds, layer adhesion gets better but the VFAs reappear so speeding up is NOT the solution IMO.
The pulley and belt change is tempting.
@Tayas, did you just change the pulleys, or the belts as well?
Which pulleys did you use?
I just swapped to toothed idlers today and saw no improvement in quality.
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I told You that it wonât change anything. For him it was just improvement because he teared down it and reassembled everything properly with belt tensioning etc.
Why You everyone donât listen to others?
Even in Voron printers they tried to change pulleys for toothed and there was almost zero difference.
Yeap⊠on my Voron 2.4 there is âbelt patternsâ at specific speeds. These are caused by motor resonant frequencies and structural vibrations that you cannot get rid off.
The solution is to know what speeds these are at and not print at those speeds. Depending on the printer construction, motors and driving method used these can shift up or down in speed but they are always there.
The below is a tower printed on my old klipperised ender 3 s1 with linear rails. You can see a similar âbelt patternâ there too. Even though this one also had toothed idlers and a Cartesian setup.
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Two people posted photos of good results from switching to toothed idlers. That carries more weight than your âit wonât workâ.
But by all means, enjoy your âI told ya soâ.
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But only two:) and they had horrible quality before, than anybody else so there was other problem.
And You told Us that it didnât change w anything for You?
Believe me that more than two persons tried this pulley swapping on other printers earlier without success.
No one has posted the vfa test tower though which is a shame as itâs an objective test showing the improvement or lack thereof. Hope someone actually runs this test at some point!!
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I posted before/after results. You donât have to take my word.
Just because a pulley swap on a different printer didnât work, doesnât rule it out here. Yes, they have the same motion system type, but there are a lot of variables at play.
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But these results donât show any improvement or am I missing something?
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Now I donât understand what You are talking about?
Itâs you who wrote that after replacing pulleys to toothed one you didnât saw any difference in quality??? So what You try to argue about???
Thatâs what Iâm saying, guys. No improvement for me.
Iâve discovered something quite interesting while browsing Bambu Lab web site:
Look at the pulleys, they are toothed. 
So that mean that they have designed the axis with toothed pulleys, but for a still unknown reason they have installed the slick one.
The logic would be that we use toothed pulleys on the toothed side of the belts, and slick one on the slick side.
Iâm convinced that tooth on slick pulleys create some vibrations that are transferred to the print thatâs just aside.
Iâve to agree thatâs strange the some of us suffer from huge VFA and some other only have light VFA.
But, in my case, the fact is that Iâve had VFA on my X1C since day 1 ONLY on X axis, and I wasnât able to get rid of them with just belts tension, I spend hours trying different tensions.
So why only on X axis and nothing on Y axis ?
Iâve first changed the belts for Gates 2GT, no noticeable improvement.
Then Iâve installed the motor dampers, no improvements.
Finally Iâve exchanged the pulleys â NO MORE VFA !
Before and after on my printer :
And since nearly no more noticeable VFA :
And Iâm not the only one obtaining such good results, some others (who didnât post their results here) changed the pulleys after having seen my results, and they also have lot less VFA after.
Hard to believe we are just lucky.
Most probably the toothed pulleys arenât the Graal that solve by themselves the VFA, but Iâm personally convinced they are part of the solution.
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Are you doing anything special for belt tensioning/squaring or just using the OEM tensioners with any special care?
Nothing too special, I follow more or less the Bambu procedure, I just ensure that the belts doesnât move up and down too much on the back pulleys.
For this I only screw one screw, then I move the print head and find the best orientation of the back tensionner. Once I find the âsweet spotâ I screw the second screw.
One side after the other.
Dear everyone who is experiencing severe banding issues, like more than is shown in most pictures above:
There is a chance, that your print bed is out of level, which causes severe banding that is not associated to a particular axis, even forms a wave pattern around cylindrical objects.
This can be caused by the bed colliding with some object on the way down. This causes the z-timing belt to skip on one of the pulleys. It can be rectified rather easily by following the second âoperationâ on this wiki page: en/x1/troubleshooting/z-timing-pulley (on the bambulab wiki, stupidly wonât let me post the link here)
This happened to me on a brand new X1C when I accidentally had moved the styrofoam underneath the bed before the initial homing. Lots of headscratching and trying out stuff from this thread later, I found out that this caused the severe banding. Thanks to @AdamBingham_1477722 on printables who posted that hint as a comment to the âsquareness check adaptersâ.
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arenât the belts already gates? just not branded?
Definitely not.
The stock belts are all black and 1.4mm thick.
Gates belt is brown on the toothed side and 1.6mm thick.