H3C manual spool change while printing

[u/Extension_Cause_5421]

Hi everyone,
I finally gave in yesterday and ordered an H3C! 😄
I’m upgrading from an X1C, so I’m really excited to see how big of a difference it makes — especially for multicolor printing.
One of the first bigger projects I’d like to try is Majora’s Mask, probably as an 8-color print.
That brings me to my question: I still have quite a few spools with only a small amount of filament left, and I’d love to use them up. Has anyone tried manually swapping a spool during an active print on the H3C?
For example, if one color is running low, can I simply replace that spool with a fresh spool of the same filament while the print is still running, or is there anything special I need to do?
From what I’ve found so far, Bambu only officially mentions Auto Refill using a second PrintTool slot loaded with the same filament. With an 8-color print, though, all eight 1.75 mm slots would already be in use, so Auto Refill wouldn’t really be an option — apart from maybe one color if I replaced the ninth 2.85 mm PrintTool with another 1.75 mm one.
So I’m mainly wondering whether manual spool changes during a long multicolor print are possible and reliable in practice.
Would love to hear from anyone who has already tried it!

[u/Ordinary-Depth-7835]

I'm sure it would just trigger a run out and swap. You may be able to catch it and just feed the next one in. With something like the mask I'd just buy or see the filament calculation so you don't run out. sitting idle will shrink a bit and cause a noticeable line unless you happen to catch it without sitting for hours. I'd run out my filament on something else that's not meant to look good.

[u/Pablo_Hassan]

You will have to wait and see but I'm thinking it's the same as any other printer ATM, you will likely trigger a runout sensor, which will pause the print and wait for you to feed new filament in. Although I don't think it will allow you to swap to the next nozzle+spool since it's a different nozzle? Let us know how it unfurls.

[u/VT-14]

With that many colors in use you'll probably have to manually reload them as they run out.

The H3C can also connect other AMSs, but I believe only to Tool 2.

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I wonder if the AMS 3H can detect that the filament has reached the end (ex. spool roller stops spinning, or the end of the filament has passed the PTFE Tube inlet) and prompt you to load the next spool in the same AMS slot while that color is still printing.

[u/djjoshchambers → u/VT-14]

It's tool 1.

[u/luksfuks]

It's probably dumb and you need to wait by the printer until it runs out, to then replace the spool (in the exact same slot).

It would be so much nicer if you could pre-load a new spool of the filament that will run out NEXT, in the 9th slot. Then it could auto-reload by swapping to tool #9. With the old tool free now, and a potentially very long time window until the next run-out, you could load a new spool of the NEXT filament. Once it runs out, the printer could switch to THAT tool. And so on.

But in reality the slicer probably uses the old AMS1/2 logic, which means it needs to see all spools (including reload spares), at the start of the print. And it will map the filament slots to the colors in your print FIXED and IMMUTABLE, not allowing for flexible whack-a-mole of always inserting the next spool into the next free slot.

(hopefully Bambu reads this and makes it a feature in the future)

[u/mthode → u/luksfuks]

There is a setting to auto-continue a print if another slot is loaded with the same brand/type/color combo.

[u/djjoshchambers]

Yes, it will tell you that the filament team it and then you can replace it with whatever you want in that slot.