Bambu Lab is once more in hot water after user Moreiras3D posted a video of a melted A1 3D printer to Instagram. The footage shows an A1 with its side completely melted down to the metal chassis, but some of the key details behind the incident remain unknown. The resulting heat appears to have been powerful enough that another A1 sitting next to it has a damaged cord.
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The video itself does not explain what happened, and plays a Contemporary Brazilian gospel soundtrack. The second half of the video shows a young boy unboxing a new A1 while watching an assembly video by StlFlix, who also hails from Brazil. The comments are mostly in Portuguese, but sifting through them with the help of Google Gemini to translate, we get some of the story.
“My machine has been in use for 3 months and already has recent reports from several others that the same thing happened,” said Moreiras3D. In a follow-up reply, he notes the printer was on a surge protector, but that the fire started on the machine itself, not the outlet.
At first glance, it would appear this is the result of a faulty NTC thermistor we reported on in January. At that time, YouTuber Grant Posner (3D Musketeers) was finding an alarming number of A1 printers with charred or melted cases, but none appeared as severe as this one from Moreiras3D.
The known issue stems from the A1’s AC power distribution board operating above normal temperatures and posing a risk of fire. The AC power board uses an NTC thermistor to limit inrush current and is active only while the printer is rapidly warming up. Bambu Lab responded that no fires had been reported at that time, and that its printers comply with applicable safety standards and use flame-retardant materials. The company also said it would fix the issue on printers going forward.
The red arrow in the image points to the NTC on the A1’s power board.
Some disgruntled community members on BambuLab’s Reddit are of the opinion that the A1 needs to be recalled, with Louis Rossmann echoing their sentiments with a video titled “Bambu Lab PR Dumpster fire is turning into a literal one”.
However, others are doubtful that Moreiras3D’s A1 caught fire due to the same NTC thermistor issue. For one thing, the machine is relatively new and most likely from the stock that Bambu manufactured after correcting the faulty part.
While Bambu told Tom’s Hardware in January that conditions causing the NTC thermistor to fail were rare, they had changed the hardware in Q3 2025, which could be well over 8 months ago.
Furthermore, some sharp-eyed Redditors questioned the video, filmed well after the fire, but showing a large melted plastic object under a dish towel. Below, we pieced together a series of images from the Instagram reel to give a clearer view of the whole desk layout.
“So that burned mess between the two A1 printers would point to something really big going on there, and the damage to the side of the A1 on the right could be caused by proximity to whatever happened in the middle. Without any video evidence of the fire happening, we're left to speculate with the video we have available (and some mildly annoying music). I'm not saying the A1 didn't have a failure, but I'm not going to make the evidence fit the narrative; it has to be the other way around for this to work,” said Redditor Spyglass.
Grant Posner, posting under his Reddit handle Mobius1ace5, confirmed he has reached out to the owner of the burnt machine in hopes of solving this mystery.
“Yes I am assuming it's stemming from the NTC. The rags there likely factor in some too. And no, it's at the same place I believe. It's why we have contacted the user to not only get more info but to try and buy the machine so we can have it tested. Anything else is pure conjecture,” he said.
