Skipping hobbed gear after x number of layers

Hello all,

I'm hoping I can correctly describe my symptoms along with what I've to trouble shoot. Hopefully someone has a suggestion that I haven't yet tried so here goes...

As of late, My printers extruder's hobbed gear will start skipping after several perfect layers, like the hot-end is now too cool to melt the plastic. First off, this isn't the issue. I've used several 3rd party thermometers to measure temperature, and the thermistor in the hot end is in fact reading the correct temperature which also means the heater cartrige is working fine too. It never drops, or deviates from the assigned temp. I've changed out the plastic to several different types, same thing. Manually forcing the plastic through is simple, there are no obstructions and the hot end melts with no problems. I've taken the hot-end appart and cleaned it out. No issues there. Clear with no obstructions, and there are no kinks or issues with the nylon insert in the heat brake (yeah, it's a cheaper hot-end). I've checked the tension/force between the idler bearing and the hobbed gear. That really hasn't changed since I've gotten the printer, but I checked it anyways. Checked connections with the stepper motor, there's plenty of torque there, no issues.

I just can't figure out what's going on. I start a print, everything works awesome for several layers, then just starts skipping like the hot end cooled down. I don't get it. I'll stop the print, yet be able extrude filament like nothing's wrong.

If anyone's experienced this issue, please let me know what you did to fix. Any help would be greatly appreciated.
I'll provide any/all information going forward.

The printer up to this point has been a work horse with few problems. I just can't figure it out.

Thanks very much in advance.

Sounds like heat is creeping up past the heat break in your hotend, causing the filament to jam before it enters the melt zone. Try attaching a fan to the heatsink area so that the top stays cool.

Thank you! I'll definitely try that. That would make sense since the heat sink is fairly small, as is the fan. Maybe the fan's slowing down due to age or dust build up?

Thanks again!

I have ordered an E3D V6, as I'm going to change my Direct drive into a bowden drive. The whole extruder setup is quite heavy sitting on the Z-Gantry, but that's a different story...

Also, is your hotend an all-metal or lined hotend? Mine (see signature) would grind the filament after a while or so, and dipping a little bit of the filament in canola oil solved all of my problems. I re-season it every couple weeks, just to make sure, but its not the oil being present on the filament that helps, it actually coats the metal somehow and creates a thin film that helps it slide.. Anyway, I would try that if its an all metal.

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Master Tinkerer