One more thing that I think Y splitter type dual material is useful is when you print some extra large print that you know 1kg spool not going to be enough and material you want don’t have bigger spool available, you put 2 spools on and when first spool run out the filament sensor tell controller to switch to second spool. Wonder if any firmware have this feature, I know it’s very specific use but would be nice to have when you need it.(Or just tool change script is enough, I don’t know)
At work, we have a Fortus 900mc, and it has 2 canisters (enclosed filament spool) for both model and support material. When one runs out, it switches to the other one. Except, the way it keeps track is with a digital counter. Each canister is 92.6 cubic inches of material, and it calculates that a print took 12.6, knows it has 80 cubic inches left (printed part size is calculated from settings in slicing software).
So, it is possible.
Would be interesting to see how a hobbyist reaches a solution.
Most firmwares can already hot-pause and/or run arbitrary code when a filament sensor triggers. I suppose the Y splitter would let you automate the switching but how often does this case really come up to make it worth automating?
Might not happen very often but I agree it would be a nice feature when you need it. Could be made to work with any multi head/feed setup. A small amount of code added to filament run out sensors would allow firmware to detect that a second spool is present and start using it if the first runs out.
Just to be able to run the last bit of filament off a spool and not wonder is this print small enough!! I would use it.
One thing to note (and your extruder may operate differently, so I can’t say with 100% certainty), but you might want to back out the filament from the nozzle before feeding the next spool.
Otherwise, the old filament may block/deflect the new filament coming in, and make the whole process NULL/VOID.
Besides that, I imagine it would be a fairly straight forward set up… In my head, anyways, it’s fairly straight forward/simple.
I want to do similar eventually, but I currently avoid the problem by getting larger spools or by weighing the spool against its empty counterpart, so I know how much I have left.