Less language filters over there…
I’m still waiting for the plot twist that grease was missing and that’s why not a single photo of the screws was taken. 
Although it doesn’t change anything, because either way it has to be replaced.
why make another thread when you have one already ?
I am confused as the other thread isnt mine?
Here is all the info, Printer has roughly 2500 hours, greased every week as part of the farm maintenance, grease was metallic free every cleaning till the guide nut failed. There was no early warning signs, no particles no wobble. After failing the grease is filled with brass particles. Looks like it was ground away as the particle’s are very fine and only notable on a white paper towel with a flashlight however the grease is currently copper tinted so its a dead giveaway. Not sure what else to include. The other 2 leadscrews grease is clean.
I have wiped the bulk of the grease off the leadscrew and lowered the bed for pictures. Its been suggested on Reddit that some of the earlier printers may have defective leadscrews with poor machining such as a burr but I cant feel anything with my fingers. Granted that’s not very scientific. Here are the pictures to go along with my video I had posted.
Oh wtf it was showing you as the first poster for some reason. Apologies.
Since you two are different cases, its a bit worrying to see two h2d failing at the same time period, at the same part.
Maybe we should bump the thread so that people get awareness and check their brass thread thingy, maybe its a widespread early failure.
I already recived a response from support took them 12 hours to respond 
They didn’t even need the pictures they just said it needs a lead screw replacement kit and asked for the receipt of purchase to verify that its in warranty. Considering the H2D hasn’t even been out for a full year yet it has to be in warranty so that’s a bit frustrating as I am currently frantically looking for it. I found every one but this ones so far. Usually I just buy the replacement parts from them but sadly they don’t offer the kit for sale. Lets hope they start too as they already have everything you need in a kit.
It doesn’t necessarily have to be under warranty, but most of the time a unit that’s less than a year old still is.
Speaking of which, I’m already on my third
https://eu.store.bambulab.com/products/h2-series-tool-head-with-x-axis-assembly?id=54196971635036
so far, and my printer isn’t even a year old yet. I really hope this is the last major swap I have to do if I’m ever going to have anything resembling reasonable economics on this machine. All the parts have been replaced under warranty, BUT while the printer is in pieces I can’t crank out RC parts and everything else I’m supposed to be producing.
At this rate I’m half expecting I’ll be replacing the lead screws soon too – this machine prints great when it’s in one piece, but it’s starting to feel like it’s carrying some kind of curse.
Its funny that someone made this! Printing now for a band aid fix. Ironically I was saying how reliable my P1S printers are in my farm then last night one mid print decided to fully raise the plate and slam the nozzle into the build plate and dig a hole. Bent the nozzle, killed the plate. Joy.
To be fair, I’ve built a few printers over the years, including a release day Prusa MK3 and have never greased a lead screw prior to getting the H2D and have never had a POM nut fail like that. My MK3 still happily chugs along with ungreased lead screws. In fact when I built my MK3 greasing the lead screws was never even mentioned.
Do remember that the setup of Bambu CoreXY printers is different than the MK3. Bambu printers have 3 Z lead screws driven by one stepper which are connected via a belt. The MK3 has 2 Z lead screws that have their own stepper. This system has double the drive torque on hand.
Interesting. In the manual for my Prusa MK3S+ it actually says that the smooth rods should be lubricated, so that’s what I followed.
If you had an earlier model, they might have changed that recommendation for the MK3S series over time.
Back then I used CLP and SMX on mine, which was probably just as questionable as not using anything at all, but the printer is still running fine today.
Wow that nut is completely reamed out. And within one week, it went from fresh grease and no signs of glitter to completely consumed. The big chunk makes me think the threads broke off mostly in one go, and then it ground itself down or something. I wonder what happened.
Honestly, the grease didn’t look funny at all even right before I started that print! There is a oddity tho. When I put on that printed part it moves smooth like butter up and down but there’s a spot that it flutters and the rod has a vibration as it passes over the spot with speed. Perhaps a slight bend in the rod or poor machining.
Initially the MK3’s shipped with ungreased linear bearings, they require grease. I’m talking about the lead screws, there’s nothing that says they should be greased. That being said, I see from the picture above that BL is using brass nuts where most others use POM/Delrin nuts. I never used a printer with brass nuts so will say yes they need grease. As far as oiling the smooth rods goes… If you have good bearings they should be a sealed system so the only thing oiling the rods will do is prevent rust and maybe help keep the rubber seals pliable.
Could probably find an off the shelf replacement somewhere.
Just a small nuance here: Prusa’s guidance actually depends on the machine/design.
- For the i3/MK3 family, Prusa explicitly says not to lubricate the Z trapezoid nuts or the threaded Z leadscrews (see their i3 maintenance guide):
https://help.prusa3d.com/article/i3-printer-regular-maintenance_2072 - For the Prusa XL, Prusa explicitly says the opposite:
After ~500 hours of print time, lubricate the Z-axis leadscrews.
Prusa XL maintenance guide:
https://help.prusa3d.com/article/regular-printer-maintenance-xl_401237
So yes — it can be material/design dependent. A Delrin/POM nut is typically self-lubricating and often doesn’t require grease, while metal-on-metal generally benefits from lubrication (but only when the manufacturer calls for it). Also, as always, too much lubricant can be counterproductive because it attracts dust and turns into abrasive paste — moderation + cleaning matters.
I wonder how much of this is caused by the violent up and down movement the bed does, before bed leveling. I assume its to release any grab that the brass nuts have on the z screws, but probably rough on deez nutz
I hope you didn’t use a GF infused filament here. Otherwise the rod is the next part to fail.