@deckingman said in Core-XY based on Rat Rig V-Core and Duet 2 Ethernet:
@grizewald As you say, the filament would need to really out of spec to jam in a 1.95 -1.97 mm hole. I wonder if maybe a bit of swarf (metal or plastic) or grit got attached to the filament and found it's way in?
I don't think so. When I think about it, the catastrophic jam that forced me to dismantle the hot end to clear it was almost certainly caused by heat creep. The makers of the Mosquito suggest that their tiny little 25mm fan should be OK run at 70% of full speed. That might be OK when running PETG or a similar high temperature filament, but when there isn't a clear path behind the hot end's heat break so that the tiny amount of air that the fan moves can flow freely, the heat break quite quickly gets hot enough to cause a jam with PLA.
In my case, the duct to the part cooling fan and part of the hot end mount run down behind the hot end's heat sink:
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This compromises the overall air flow and even at 100%, the little 25mm fan just can't keep up. Maybe if I moved it to an always on fan connection, but in the end, I printed an adapter so that I could use an E3D 30mm fan. That keeps the heat break cool enough to print PLA now.
The other jams I had were certainly because the filament was too wide, but in those cases, the filament actually started to bind in the feed tube from my dry box to the printer. I run all my filament from a modified Polybox with PTFE tubes all the way from the box to the extruder. When not being used for printing, my spools of filament are stored in mylar bags with a 100g pouch of desiccant until they are needed.
Due to a lack of room in my apartment while I'm waiting for daughter number two to move out, my printer lives in my kitchen and that's probably the worst place possible from the point of view of humidity. Even so, this summer has been particularly humid here in Sweden and it's always good to be able to keep your filament dry and dust free anyway.
