Hidden Weaknesses in H2D at High-Temp Operation

Bambu Lab H2D
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It appears that the H2D may not perform as professionally as it has been marketed. While it offers versatile tools such as laser, pen, and cutting modules, pushing the machine within its stated specifications reveals unexpected and hidden weaknesses.

I have been running the printer continuously for several days under high-temperature conditions—65 °C chamber, 120 °C build plate, and nozzle temperatures between 300–350 °C. After about two days of near-constant operation, the HMS system began to report unusual issues. One of the most notable was abnormal bed leveling values, which caused the printer to abort a print mid-job—even though no bed leveling occurs during active printing. This resulted in a lost print without any external cause. The plate was stable, the nozzle was clean, and no filament debris was present under the build plate.

Other anomalies included filament loading errors, even while printing continued normally. While this did not stop the job, it was still a concerning inconsistency. These are just a few examples from a wider set of errors observed when operating at the higher end of the temperature specifications for extended periods.

For troubleshooting, I disassembled the extruder, inspected and replaced every PTFE tube from the AMS to the printhead, and cleaned the build plate meticulously. No issues were found, confirming with certainty that the cause lies elsewhere in the system.

Repeating the procedure after cooling the system back to room temperature produced the same errors again after approximately 48 hours of continuous high-temperature printing. This time, I used only small test models to avoid wasting valuable material.

Something to keep in mind when pushing the machine at the upper end of its specifications: the most critical problems are those that immediately stop an active print. These not only waste valuable material but also result in direct financial loss, making the issue more than just an irritation.

The concerning aspect is that there seems to be little interest from Bambu Lab in identifying the root cause. It is difficult to believe the system has been thoroughly stress-tested under continuous high-temperature operation, as these errors appear consistently when running at the upper end of the specifications. The issue may be linked to prolonged high chamber and bed temperatures without cooldown intervals. Investigating this is time-consuming, and frankly, it is the type of validation testing that should have been carried out by the manufacturer in the first place.

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Sounds like electronics issue to me.

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abnormal bed leveling sounds like A. the strain gauge / load cell is either failing or B. the bed tension screws have loosened over the heat up cycles. I definitely had similar experience with B: My bed tramming has drifted after roughly 900 hours of printing mixed materials. It was done with an indicator dial. I didn’t do too much high temp printing (unlike what you’ve been doing) so I guess your bed tramming might be off even more.

AFAIK H2D uses the same kind of eddy current based load cell, so this might help. If there’s nothing wrong with the nozzle’s metal fins, or the hotend seats, or the bed traming, then I think it’s probably time for you to submit a ticket.

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This is unbelievable, especially considering the cost of the machine, the market segment it’s positioned in, and above all the fact that Bambu Lab’s CEO stated they had built 1,500 prototypes over the past few years before reaching the final product. At this point, it seems like they only printed Benchies in PLA… :sweat_smile:

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My bed is not off in the slightest. I’ve performed all the checks, and these issues would not be detected during printing anyway, so the error is either misplaced, delayed, or simply incorrect. I also use a dial indicator to verify, and it’s still within the accuracy I require. That said, it’s good advice for anyone who might actually encounter such problems.

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Perhaps it took so long to build and test all the prototypes that the final product was rushed into production before it was properly stress-tested? :wink:

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Interesting thought—what electronics are you thinking of specifically? The system is rated for a 65 °C chamber, 120 °C build plate, and up to 350 °C nozzle temperature. The machine is completely original with no modifications at all.

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Call it whatever you want, it’s still serious given the cost of the machine and the company’s name, in my opinion.

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I think it’s either the TH board or eddy current sensor. Not a total failure, just not very stable or reliable under continuous high temp load.

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Yeah, something definitely doesn’t like the heat—that’s a fact. :wink:
I’ll see if I can run more tests this week and try to rule out components one by one. I do need the machine for actual work, but I also want to understand what happens after extended periods at high temperature, since some of the reported errors are clearly incorrect.

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Just any of the boards or connections that could be impacted by heat/expansion. It could be an inherent design fault or maybe you’re just unlucky and have a problem with your machine. It’s good you’re raising this so others can comment. I’ve printed some PA and ASA on mine, both printed great with no issues. I’ve not been running that high temp though continuously.

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Have you raised a ticket with Bambu and sent the machine logs? Maybe there’s a clue in the logs which would be useful. I appreciate it’s frustrating to have machine issues. Design flaws should be caught in their testing but there will always be some manufacturing issues impacting individual machines. Maybe you’re just unlucky in that regard.

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It is suggested to open a ticket including the log and more details. The team will be able to look into it and find out what the problem might be.

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I also read that they built 1500 prototypes. Which makes you wonder. Where are these prototypes now? Did the first wave of buyers get them? That would explain the bad QA/build issues, inconsistent issues and flaws among users, and several other factors. Also im kinda having difficulty seeing those prototypes being recycled/scrapped. After all 1500x roughly 2000$ (base price of an HD) is about 3Mil $. See where im going?

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@NothingHam Honestly, I doubt that’s how it went. From what I understood, the 1,500 prototypes were just different revisions of the same machine — from the very early versions to the more finalized ones.

I really hope it’s not like you say.

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I printed 350 hrs of ABS, similar chamber/bed temperature and the only problem I encounter is that the printer was complaining the room was too hot sometimes (error about the electronics being hot), no print failed, or bed levelling issues, but I added some fans to recirculate the air in the room to avoid getting the error.

The room was not super hot either (maybe 24C), just without nice ventilation

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It’s not like that at all. That’s simple ■■■■ talk for the sake of it.

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My room temperature is maintained at 20 °C, so that’s not what the system is complaining about.
That’s essentially what I did—maybe not in a single continuous 350-hour print, but with multiple jobs running back-to-back without any real cooldown in between. Running the heat bed at 120 °C, chamber temperature at 65 °C, and nozzle at 350 °C—with the only cooldown happening when removing parts—the chamber never dropped below 55 °C, and the build plate stayed around 99 °C at the lowest.
It’s possible I have a poorly soldered PCB, but we’ll find out soon enough, I think.

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Could this be related to them bringing out that toolhead cooling fan for the H2D Pro? When it comes out stand alone that is definitely something I would buy. If just to prevent issues.

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