symptoms of a failing printhead

[aag 5]

I am frequently getting the dreaded message: "One material appears to be empty" (which in reality means: "the Hall sensor in the feeder is not detecting any filament movement"). I have cleaned and inspected the feeder, replaced the  Bowden, and of course checked the filament. Can this be a sign that the printhead is worn out and needs to be replaced?

[SandervG 1,519]

Hi @aag, I don't think this is a sign that the printhead is worn out. Do you have it with the same material often? Which materials are you printing with mostly? You could also turn off the flow sensor if you feel like it is more cumbersome than helpful (but I can imagine that might not be your desired way forward?) 

[aag 5]

I mostly have tPLA+PVA. Contrary to expectations, it's the tPLA that gives trouble; the PVA is just fine (I dry it regularly). And it's real underextrusion, meaning that turning off the flow sensor will result in a ruined print... 😞