They sure have an instruction, here you go: Replace H2D&H2C Toohead with X-Axis Assembly | Bambu Lab Wiki
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it is a SHOCKINGLY BAD DESIGN especially since these are as they say are a consumable item and need replacing every couple of months (Bambu Support stated this to me in chat)
Even worse is that they KNOW there is an issue with printing long high temp projects but they still say these machines can print high temp filaments for long periods of time (ask that question to the chatbot and it will tell you it can, when in reality it cant
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It’s in reality a bit of false advertising. Whilst it can print at hot temperatures it also destroys itself doing it. They should really have a list of expected lifespan of “consumable” components. They also lost the y axis bearings and rods as consumables but refuse to supply or replace them if they fail
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Well.., if you are one of the unlucky people to have this happen to you, then it’s understandable to think this way. But it’s really not the case.
I’ve replaced 3 of these fans. All of which were on low hour (within 500 hours) H2 machines. Not a repeat failure on the same machine.
But here’s the kicker, I have 17 more H2 machines that have between 2000-3000+ hours that all have the original fan. All of these machines ONLY print high temp (60+ chamber / 100+ Bed) and do so with plates filled 30+ hour prints 24/7. A print ends, the plate is pulled hot, a new one slid in, and the job is restarted before losing 5 degrees in the chamber.
So if there was a real serious issue here I would most definitely see it. And judging by this thread and others like it at the time, I thought there was. I have 6 spare new hot end fans at home (in case) and haven’t had to use a single one.
Am I extremely lucky? Doubt it. I don’t think the 3 that failed should’ve failed. But to say they are all prone to failure is disengenious IMO and from what I’ve seen with my machines.
I’m hoping the fan manufacturer had some poor quality control initially and have turned that around. Because if not I would be seeing these fail left and right, but I’m not.
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Gotta love confirmation bias.
As it was shown many times, BL spec’d a fan that is not designed to work with 60+ ambient temp and suffer from a low MTTF, thus many machines fail way sooner.
And the vendor seems to have updated the fan to a max 80ºC spec. But there does not appear to be an easy way to determine which fan type you have - the vendor did not seem to change the part number. So it was a running-production cut-in and there’s going to be some span of time when both the old and new were shipping at the same time. And unfortunately, unless BBL did a purge to get rid of the old fan inventory, spare fans might be more likely to be the old fan than the new fan.
I still haven’t gotten around to doing mine. Going on 3 weeks. I’m going to lay the printer face down on the bench, across a couple of wood blocks so the touch screen and door handle aren’t taking any load. The door is recessed a few mm behind the left and right corner pieces, and my wooden blocks are as wide as the printer, so it’ll rest on the corner pieces and the glass won’t be pushed on.
In this position, with the printhead all the way at the front of the machine and the top glass cover removed, I should be able to easily get the job done. The printhead will only be a few inches away and I shouldn’t need any gymnastics to get my hands in there.
I think removing the X axis and printhead as a unit is not a good idea. If you lack the skills for an on-printer repair, you probably lack the skills for this approach, too. And I suspect there might be alignment issues during reassembly if you’re not careful… And at some level, the more parts you remove the greater your chances of messing something up.
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That makes sense as the failures I did have early on were early machines bought not soon after release. I’m guessing they must’ve addressed this quality control a few months in as I haven’t had any problems since doing the thing that causes them to fail 24/7.
I had read what you wrote elsewhere as well, when ordering the spares to have on hand. So I was not suprised seeing the same exact manufacturer sticker / part number on the replacement fans I did change (as the old one).
Kudos!
If you have something you can set the entire printer on below you, no need to angle or tip it in any fashion.
You really want to have a good lighted magnifying glass. That is a MUST. Something with a mount would make it even better, but not needed.
Also, if you know the fan is bad (like the bearing went out in it) and the plastic shroud around the fan isn’t damaged (aka blades flew off the fan).. There’s no reason to go all the way in there and replace the fan shroud as well, when you can easily just replace the fan into the old shroud already there.
Doing it this way you can even leave several cables on the 2nd board connected, just moving it out of the way sideways to gain access to the screws of the fan itself.
It will save you a whole bunch of time for sure.
The way my luck is going with my printer the only thing original in the next 3 months will be the power cord.
it really needs a whole redesign if they are stating they need changing every couple of months, having to unclip and reclip the ribbons and the plugs is bound to cause damage… it should have been kept to the K.I.S.S system (keep it stupid simple)
I don’t actually know how they designed it. Wonder if there is space to put a molex connector or something.
So I did this recently. Here are my thoughts.
- Tilting onto its front is what I did. Sat on a stool in front. Saved me from being too bent over too much.
- 40 min from unplugging it to plugging it back in. Only tools I used were a magnetic work light, pair of allens, and tweezers (for the cables). I wasn’t rushing.
- Pain? A bit. Nightmare? No.
- I suspect Bambu did it this way to save weight and didn’t anticipate that they fan would wear out so quickly/often. I think this is less of a case of a poor design and more of a case of a badly spec’ed part.
- I tried an eBay part that supposedly had better bearings and higher temp rating. I can’t tell from the looks of it if it is a different part. Time will tell I guess.
- I left the shroud in situ and just pulled the fan.
- I am less irritated at the repair and more irritated and Bambu for not offering expedited shipping. Sucks to wait 2-3 weeks for a spare part.
- I am impressed with how cheap Bambu sells parts for. This exact part with a Bosch or Porsche sticker out on it would have at least one digit added to the price.
- I didn’t wait for the fan to fully fail. I sounded like a bad bearing, I ordered a pair of replacements, and I did the repair on my own time; when it was convenient for me.
- I toyed with ordering spare everything incase I tore a ribbon cable during the process. I didn’t want to have to wait another 2-3 weeks. I the end I ordered nothing rolled the dice. I worked out.
- Careful of the cables. They are delicate.
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Update
After the advice of people on this thread I asked for the replacement unit. They are shipping the whole thing then want mine back when I’m done.
I really hope this solves it.
i got my h2d in late November and put medium use on it. By no means the 24/7 person. I do do abs some - maybe more than some. I bought the h2d to handle abs. I’m shocked this causes issues.
Really the only difference in my story versus others is that
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I didn’t have noise or issues prior to that error I pasted. Nothing. Just died
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replacing the fan didn’t fix anything.
You all claim that it makes noises or gradually dies. And when you replace it things are great again.
I’m worried that something is just monumentally f*cked on the machine since the replacing didn’t resolve the issue.
I feel like every time I tear it down and do things it’s a chance of not coming back the same.
I come from an ender 5 pro for years and it was a simple machine where the fan was optional and things worked. It’s garbage compared to the h2d - I’m not trying to say it was great. I’m just saying how upgradable and tank like it was.
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The forward and aft facing M3 machine thread screws attaching the Gantry on the left and right sides are glued in place. Seriously over lock tight. My suggestion is moving the screw in and out a little at a time. You can see the back side of the screw, so maybe some oil. I replaced these thin head screws for standard M3 socket head screws.
Yes - definitely due to operational rating temp of the fan - the operating temp is -10C to 80C. Yes the chamber can only be upto 70C but remember this is right beside the nozzles (usually 200C above, heat radiates) not to mention it is sucking air from heat sink if I remember correctly (correct me if I am wrong) easily goes above 80C during long prints.
Bambu should address this - also an issue in H2C
I agree. I’m a 60 YO Chartered Electronics Engineer who’s appalled at the TH design when it comes to maintainability. I recently had my H2S picked up for replacement after a series of replacement parts failed to resolve the original issue, but instead the constant removal and replacement of the part cooling fan, TH board etc. ended up with multiple additional issues.
I didn’t ‘choose’ this repair route - in the UK BL ‘don’t have workshops for repair’ (though note that they DO have certified resellers who do), so sending progressively more spares for the user to fit is their standard approach. I eventually demanded a replacement after replacing TH boards, MC boards, Screens, USB C cables, heatblock assemblies and eddy current sensors.
I’d happily pay double the price for a TH that’s actually maintainable!
After this experience, any future attempt at repair will involve removal of the whole X axis gantry assembly. At least that only leaves me with 2/4 easy to strip screws during disassembly and reassembly whilst making TH access FAR easier for the multitude of tiny, fragile cables and ribbons that need to be removed and replaced.
Someone here does have a mod to make this fan easier to replace - although I should also note it sounds like there was an issue with the earlier fans, and they’re coming from a different supplier now.
I did some digging, and the fan appears to be a very uncommon type, I couldn’t find an OEM supplier anywhere. At minimum, if BL was going to make such a difficult to service design, they should have spec’d a bog standard fan and put in the highest grade available.