Be careful not to install pulley with bigger flanges as the can touch the print head.
The toothed pulley isn’t the 100% solution to fix vfa, saddly.
I think that the carbon rods are also part of solution as printers doesn’t have the same amount of vfa.
I noticed that my new axis move more freely than the original one.
So your improved quality might actually come from the new rods?
Maybe i should try to install metal rods…
Could be part of the solution to reduce them.
Metal rods on Bambu is not a good idea, printer will probably rise error due to weight.
I figured I’d at least try the toothed idlers while I had a new assembly and can get everything ready before swapping. I to am wondering if your new carbon rod is influencing the results as well.
I ordered genuine Gates toothed idlers. This is the drawing I have of the pulley, except a 5mm bore. OD is the same as the original. I won’t be able to verify my method to hold the shims until I actually measure the height of the idlers.
I ordered these shims which will give me more options to fit properly. IIRC the bearings do not have a compression spacer between them inside the pulley so you want some clearance between it and the injection mold housing.
As far as I remember the original Bambu pulley are 9.5mm high, the one I’ve installed are 10mm, reason why it was difficult to install the gaskets.
gaskets here : https://fr.aliexpress.com/item/4000880527421.html
pulleys here : https://fr.aliexpress.com/item/33023133633.html
Rather sure they make no differences, as most probably all our printers (Bambu and others), use pulley from China, and they are able to produce high quality products too.
I measured 9.6mm for the Bambu and 10.3mm for the injection mold opening. Hoping the variety of metal shims will get me what I need if the idlers come in at 10mm.
Here are the idlers I ordered (M-IDLER-T-GT2-P20-6-A-P5-H100):
You can get them here as well but looks like they are sold out:
The shims to use are nylon carbon, not metal.
I’ve used the 5x7x0.3 version like the original.
Should perhaps have used thinner, but at least the pulleys are perfectly in place.
Yeah I’m not as concerned with the thickness in the case as the plastic housing will likely just deform. I think clearance issue it’s more if you have a shoulder bolted connection so you don’t compress the bearings between each other.
I’d imagine any material will be fine as long as the ID and OD allow contact only on the inner race of the bearing and prevent the bearing flanges from rubbing on the housing.
Having just replaced my X axis and belts, there was absolutely no improvement. Installing a Gates belt made it worse actually and putting a new X axis and belts more similar to OEM brought it back to a pretty original level of VFA.
At least you gave it a try, for science. I was also tempted, it’s still in my basket. I think i’m not pressing the checkout button this time.
I also tried oil and lube on the rods… nothing… (yes i know all about the warnings)
Took me some minutes to get rid of all.
I have used light oil on the Y rods and I’ve also done silicone lube on the belt and pulleys to seemingly no effect. One thread I was just reading suggested that really drenching and soaking the CF rods until all the gray residue is gone helped, but I doubt it and even so it would be very ephemeral.
Made some progress installing the Gates toothed idlers. The Gates idlers measured 10.05mm thick (9.95mm between bearing inner races) vs. Bambu smooth idlers which measured 9.6mm. The carbon rod housing only measures 10.3mm so IMO the 0.3mm nylon shims are too thick with this combination.
That being said, I definitely needed the shim pack I purchased and ended up using the 5mm OD x 7mm ID x 0.2mm TH shims. Because the stack up is a slight interference fit with the housing, I had to rethink my shim tool. I ended up re-printing without the containment surface so it made it more difficult to install but took maybe 5 minutes per side and worked on the first try for each side.
Here is the sequence:
Starting on the top side of the idler, place the shim tool on top and carefully place the shim in its opening.
Use a hex key or similar to align the shim and bearing to the bore before partially inserting the pin.
After the pin is partially inserted, turn the rod assembly over and wedge the shim between the top of the idler and housing.
Place the shim tool between the idler and housing, centered about the shim, and push inward until it bottoms out on the idler flange. At this point if all is correct, the shim will now be perfectly concentric with the pin bore.
Verify everything is in place and then continue to drive the pin inward.
I’m hoping to get around to installing the assembly this weekend. I have already completed my initial VFA testing on the original assembly as a baseline.
Thanks for the detailed description.
Hope you see an improvement. I still have this assembly in my basket, but still not convinced this will be the solution (but i hope it is).
Not directly related to the X-axis replacement or toothed idler mod, I have determined that adding Teflon tape to the frontmost smooth pulleys has improved my print quality around 20-30%. I put one piece of tape (several revolutions) on each pulley including the tooth-on-smooth and registered an overall improvement, especially on the peak vibration band. I will do more experiments to try to nail down exactly what it is, but in part I think it was that the front right pulley now has the belt tracking straight on the tooth-on-smooth pulley. The left side won’t track straight.
I just did the same, but for me i did not get much improvement.
It seems alot of people have similar VFA issues, but the solutions behave differently.
How does your belt tracking look, especially on the tooth-over-smooth pulleys? There are a lot of people claiming that squaring the axes and skewing the tensioner pulleys fixed their problems, but I think if it did it might only have been belt tracking. I’m going to try to manipulate the belt tracking on mine this weekend with strategic wrapping of the pulleys since there’s no adjustments possible elsewhere and the idler skew is very limited.
It think my belt tracking is ok’ish, but not great. It might be better than yours without the tape. That’s why it improved more in your case.
Got around to installing the new carbon rod assembly with Gates toothed idlers. Long story short, they do NOT eliminate the 2mm pitch VFA. Mine were not that bad to begin with but needed to replace my rods as they needed to be cleaned almost every print to prevent resistance so figured I’d give it a shot.
I completed VFA tests before and after and observed no significant difference. I tried to keep the variables identical between each test so hardware changes were the only thing that would affect the outcome. For the toothed idlers I ended up changing the idlers(Gates), carbon rods, belts (Bambu) and did a through cleaning.
Prior to the each VFA test:
Clean carbon rods with IPA until no black residue was observed.
Tension belts according to Bambu Labs wiki
Complete a machine calibration
I then used the same sliced file between tests using Orcaslicer’s VFA test. Speeds are from 50-200mm/s with a 10mm/s step. Printed in Bambu Basic PETG in Black @ 270c. Both tested were printed directly from a PrintDry Pro 3 at 65c.
My recommendation is to complete your VFA test and determine which speed gives you the best result and avoid the resonant speeds and confirming that you’re not running at those after it is sliced in the preview. If you need to print faster then adjust your temperature to give you an appropriate strength, noting that as you increase temperature, the VFAs will tend to move to extend to a higher speed as well. My printer looks best at 50mm/s or 150mm/s+ for this particular filament.
I now suspect there is some sort of resonance (maybe in the belt itself) causing the artifacts. I may look at playing around with squaring the gantry and what not but don’t believe it will have an effect.
Do you mean helical gears?
I have a p1s, have opened the extruder quite a few times, also replaced it with a complete new one, it has helical gears.
I have the 2mm VFA problem, quite a bit actually.
