Found something quite annoying. A roll of PETG seriously need drying, and it’s required for my next print, so I thought I’d dry it while working with the laser. Nope, not allowed. Why??? The AMS in question has it’s own power supply so that shouldn’t be an issue
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Yeah, that’s definitely not ideal. They should consider adding a menu option to specify whether external power supplies are being used for the AMS. It’s likely that the AMS’s internal H2D power source doesn’t have a current sensor, which might explain why the AMS heater gets turned off in laser or cutter mode to prevent overloading the internal supply, I’d guess.
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It knows if there’s a power supply being used, there’s an icon for it when looking at your AMSes on the printer and if you don’t have one there’s a warning that the drying function won’t work as well when it’s running
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Oh, that’s right I forgot about seeing the green icons when I connected my two external power supplies to the AMS units. Since they have feedback to the printer, a firmware update might be the solution so you can dry filaments.
Hopefully, if not then at least I hope they explain what their reasoning for this is
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Do they have to explain anything? That’s just the way it was designed, nothing to fix or change. If you want to dry filament while using the laser just get a Sunlu dryer or something. Do you have an oven?
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Do they have to? No. Should they? Yes. This limitation is seemingly arbitrary, occluding your reasoning for a limitation provides a poor customer experience. I’m not throwing my filament in my oven when I paid near $700 to have 2 reliable 4-spool dryers when there is seemingly no reason that I can’t use them outside of “because we said so”
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You just assume its “because we said so”… As an engineer that designs consumer electronics this is one of my biggest annoyances with people and what they feel they are “entitled” to. Not being able to dry while using the laser is an extremely petty complaint IMHO.
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Are you actually trolling or is your reading comprehension lacking that much? Currently, without comment from Bambu, we are at the equivalent of “because we said so”. As they haven’t given a reason, that is the default state. I’m sure there may be an actual reason, but until that is presented by the company that made the decision, it doesn’t matter what that reason is.
And no, expecting to use a product I purchased for it’s intended use while utilizing a completely unrelated featureset of the parent hardware is not entitlement, it is expecting base features on expensive hardware to work as advertised. Especially when this limitation is not publicized anywhere I can find.
EDIT: I’ve been using the laser over the past 8 hours, if I could dry my filament I would have been able to start a print for a project I’m working on tonight, which would have lined up perfectly as I need to put weights in within the 10-14 hour marks. Now I have to dry overnight and wait until tomorrow night to start it because I’m not going to be here tomorrow evening. This seemingly unnecessary limitation is costing me over 20 hours on my current project
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I have no sympathy… Using your laser over the past 8 hours is a long time, might want to clean your printer while the filament is drying. Like I said, petty complaint. Seems fairly evident to me that BL is hyper focused on the laser being the only feature enabled to run on the printer. Whether it be for safety or power consumption reasons, I care not. Now that you know the laser and dryer can’t run at the same time perhaps you can plan better in the future.
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Learning that you think drying filament in a box that is not within the printer that is running on its own power supply might be because of safety got a genuine laugh out of me, thank you. I never asked for your sympathy but the fact that you think it’s important to me is cute, though very ego driven
Well I guess you’re smarter than me… Maybe it is because BL “said so”? Sucks for you. 
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Whether from the perspective of customers or companies involved in product manufacturing, this feature could be highly valuable. The absence of a drying function may impact the user experience. For some buyers, this could be a deciding factor potentially leading them to choose a competitor’s product instead.
Customer feedback is a key driver of innovation. It often inspires new features, software updates, and product improvements that enhance long-term value.
It’s possible the Bambu Lab team is taking a phased approach, and this functionality may be introduced in a future firmware update only time will tell.
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Oh right, let’s not explain how our machines actually work. That’ll surely go great for both marketing and support. No confusion, no returns, no community backlash, just smooth sailing, right?
I mean, who needs clarity when you can just let users find out the hard way that two features don’t play nice, despite being presented like they should? Because obviously, it’s the customer’s fault for assuming things in a premium ecosystem.
And suggesting people just buy extra gear like a Sunlu dryer to work around it? What is this, some RepRap side project? This is supposed to be a polished, integrated experience, not a DIY scavenger hunt.
If we’ve reached the point where “it just works that way” is a valid explanation, maybe next time just ship the manual as a cryptic poem and call it a feature.
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Dang… My reply was kinda bad, I’ll blame lack of sleep or some such caffeine deficiency. I apologize to OP. For real though, filament dryers are handy to have around. Would not being able to dry while using the laser be a deal breaker for the laser combo? If yes, then I feel bad for you. If not, then hopefully one day they add the feature. But I doubt it, as it “seems” to me they are keeping both features totally independent.
Nobody ever reads a manual… That’s what YouTube is for.
All I gonna say is: after reading this comment I’m assuming products you designed could be much better. Your approach sucks.
user feedback is the most valuable tool of any designer
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Instead of limiting the feature with a fixed “Not drying while laser/cutter is installed” restriction, I think it would be much more useful if the drying function were made independent and able to operate even when the printer is turned off.
While I usually keep my printers running, there are times when I power them down—and it would be great if the drying feature could still function in those cases.
As it stands now, even a simple reboot will cancel the drying process. So if you’re drying filament and there’s a brief power surge or restart, the drying cycle is interrupted and doesn’t resume. That’s not ideal for consistency or reliability.
If drying were handled as a standalone process, it could simply resume where it left off after power is restored—continuing the remaining drying time—or alternatively, it could just start a full drying cycle again to be safe. Either approach would be far more robust than the current implementation.
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Infact im returning here couple days later to say that ams drying is effectively useless. Temp hardly is maintained and is enough to only dry veeery basic mats. Even if you set it high, then you gotta wait like an hour for it to cooldown, OR open the lid and waste the drying, just to be able to print, otherwise you get an error that says its temp is too high to read nfc tags and feed. Funnily the error code and title return 0 results both on google and bbl wiki, and the qr just takes you to wiki error codes pages where its nowhere to be found.
In the end I concluded I am more than happy with my 2x S4’s and just added 2 more to the arsenal. Yes I need them , all of them are drying constanstly and full, and plus, i found them for about 60euroes “secondhand” but with sealed box, so id say…1.5hand? lol.
I guess ams drying is ok for the people who just print once in a while and dont care to wait for a day or two before firing up that one print, but in my case I didnt have downtime for months and months, heck i didnt even have a chance to print couple things i need for myself lol.
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Running four S4 dryers 24/7 is certainly one way to keep humidity in check—but at that point, I have to ask: are we still talking about print quality, or are we slowly drifting into filament prep becoming a full-time occupation?
It makes me wonder about the actual economics here. If all four dryers are constantly running, that’s quite a bit of power consumption—not to mention heat, space, and noise. One has to ask: how much of that overhead is silently being baked into the cost of every printed part?
Because unless you’re producing commercial-grade parts with strict environmental specs, the return on investment might be… let’s say, questionable. Sure, dry filament is better. But if the drying infrastructure ends up costing more than the prints themselves, is it really the AMS that’s underperforming—or are we simply overengineering the solution?
For comparison, I can dry 7 spools at 85 °C, 5 spools at 300 °C (if needed), and whatever the AMS 2 units can handle (I have 3 of them). But between prints, all my spools are stored in a sealed enclosure that keeps humidity under 20% RH at room temperature. My dryers only run when actually needed—not as a background soundtrack for the workshop.
That said, I’m not printing for resale. Everything I produce is for my ultralight aircrafts, where reliability matters—but wasteful overkill doesn’t. So maybe it’s a matter of priorities. Still… four S4s running full-time? That sounds more like a filament rehab center than a print workflow. 
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There are def better and cheaper ways of (really) drying filament, instead of just heating it up and thinking its drier.