Snapmaker 2.0: Self-Improvement Programme: Filament Path

These two designs relocate the two filament spools for the dual extruder inside the A350 enclosure and facilitate hot swapping by providing a storage bin for the dual extruder facilitating hot-swap without unloading the filament:

As well as being more compact, this layout allows the filament spools to benefit from the heating and drying I have implemented inside the enclosure. It seems like it should be better to have the spools pre-conditioned to the printing environment inside the enclosure.

However I have run into a problem I’d welcome any input on from other’s experience. I’ve found that if I leave the filaments loaded over night, often the filament has broken, sometimes in more than one place, between the end of the PTFE tube and the spool. I think this is because of the natural bend in the filament due to the curve of the spool introducing a stress as the temperature drops. I am experimenting with ways of keeping tension on the filament when not in use.


Very nice.

I have found that the less bent my filament is, the longer it can be exposed to open air before becoming brittle and breaking. I don’t have an enclosure, and I’m very low volume.

I’m surprised to hear that your filament breaks overnight though. I have Hatchbox filament, and I can usually leave it exposed to the room for several weeks before it gets brittle enough to break. When it does get brittle, usually all of the filament that has been unrolled is brittle. My original is tricky to load the filament on, and needs very straight filament. So the act of straightening the filament to load it will break off any brittle filament.

How humid is it where you live? I’m near the desert, so humidity this time of year is usually below 10%.

It is much more humid here. Typically during summer it is around 80%. I have a dehumidifier in the enclosure, but it is only able to reduce this to about 60%. The printer is in an shed outside, so temperatures drop significantly overnight when the printer is not in use. I am using Snapmaker brand filament and breakages during printing are rare. I would agree that the natural bend the filament acquires on the spool is part of the problem as it does get worse as the spool becomes depleted. I may have made matters worse by having a long horizontal run of filament in my setup. Mostly this is supported by PTFE tubing, but there is an exposed length between the end of the tube and the spool which is were breakages usually occur.

I have used the filament in the enclosure and depending on what you are printing, how long it prints, and the temps needed for build plate I have had issues with the filament softening too much from the heat. Which lead to grinding and sticking in the extruder.

I did like the compactness of having spools inside the enclosure, but the filament softening became an issue for me too often.