Print bugged on first layer

Hello all,

I was printing a phone case and had almost finished the first layer when I noticed the extruder mechanism was struggling: it couldn’t manage to push the filament anymore, and as I watched, there was less and less plastic extruding out. I tried pushing the filament myself instead of the extruder, but nothing more came out. Before long I stopped the print, and to my surprise, as the printer head lifted and went back to home, plastic started extruding freely and coming out as easily as usual…


(You can see the infill on the right fading away to nothing, and then the plastic extruding suddenly where the print head was lifted)
And sure enough, next print I tried everything extruded as usual.
So what do you think was the problem? I would like to understand before I try reprinting the phone case again.

Could be something was partially blocking the extruder and it passed through so it could print properly again.

Could be heat creep causing the filament to expand in the nozzle. After the nozzle cooled down it went back to normal.

Could be the boden tube lifted a bit and let molten filament swell out into the nozzle and jam things up. Not as likely as the others since the problem is less likely to go away without a fix.

I think your suggestions don’t quite fit the situation: a blockage in the extruder not really, because the “unblockage” coincided too exactly with when I stopped the print and the head lifted up. Heat creap neither, because once again, the flow of filament started again as soon as the head lifted up, way before the nozzle could’ve cooled down… But thanks for the help anyway, it’s a tough one :upside_down_face:
So it’s mysterious what was the problem! I suppose I’ll have to just go ahead and print the case again while hoping for the best.

Could just be gremlins, they are everywhere.

Oh well this times it worked fine, so I guess it was a one time bug that I’ll hopefully not see again