After some serious squeaky, grindy noise appeared, Bambu support suggested I apply their lubricating grease here:
The grease blob is visible behind the belt on the picture. That puts the grease in direct contact with the smooth side of the belt, since the bulley will turnand disperse the grease along the belt. Is this something you’d do?
I would be surprised if the grease made it into the pulley, Probably a few drops of lite machine oil would of been better.
If the idea is to grease the pulley’s axle, I agree with you. Support seemed to insist on greasing “the flange”. Is it the same thing? My English is usually good, but I seem to struggle with that word.
I think they might be referring to the raised edge of the pulley that keeps the belt in place, rather than the axle itself. If that’s the case, it’s odd advice, since grease on that surface could easily get on the belt and cause slipping over time. It might be worth double-checking with support for clarification on what exactly they mean by “flange” here.
I suspect that maybe, just maybe, they’re attributing the noise I mentioned to the edge of the belt rubbing on the flange. If so, that’s an odd thing. The noise sounds more metallic than anything else.
Is that picture from Bambu? That is a very large blob of grease that will mostly squeeze out to the sides. I can only see it making a mess and collecting dirt.
The two flanges of the pulley are the raised sides that keep the belt centered.
I would first try a drop of oil on the side of the bearing where the rotation actually takes place. If the noise persists, then applying a thin film of a silicone grease where the flange rubs the edge of the belt might help.
I would imagine if the belt is rubbing there it’s slightly off center? Maybe a silicone based grease is ok, otherwise avoid petroleums as they vulcanize rubber. (I think the belt is standard fiberglass rubber?)
I wondered about this myself as I’ve had a grindy noise appear at 2400 hours. Thinking of retightening belts as I think the release of the spring mechanisms allows it to recenter the belts iirc… it’s been awhile and I’ve flushed that info lol
I just thpught about it. At work we have some big W&H printing presses. We were having issues with belt noise and the W&H tech put grease on it which did make the noise go away. He said every time we change to belt to do that. So maybe thats it, I’m not sure hopefully it will not get on the build plate or print thou.
Some of those idlers are only mounted at one end of the axle. That’s great when new and tension on the belt hasn’t gradually distorted and bent the axle.
After a while, though, belt tension can bend the idler shaft a little which angles the pulley a little and lets the belt ride the side of the idler and rub against the flange to make the squeak.
I would avoid getting oil or grease on the belts—not because it would damage them, but because it tends to attract dust, which then gets distributed throughout the system.
I’d recommend starting with a dry PTFE lubricant. If that’s not effective enough, you could try a low-viscosity PTFE oil, but make sure to avoid contact with the belts.
