Cartridge heater losing power?

I was just wondering if this might be the case with all cartridge heaters as they are used and wear out. Mine seems to be outputting less heat than it once was.

I have a cartridge heater in my E3D V6, on my Taz4. I never had this problem before. But, I just had a few failed prints, that looked like a clogged nozzle (a notch chewed in the filament and clearly a very week extrusion on the last few layers before the print failed).

The nozzle didn’t actually seem to have an obstruction, though, since every time I fed the filament by hand, it flowed fine, and the print started just fine every time I reset the print.

I watched my nozzle temps as I jogged my extruder with part-cooling fan on 100%. The nozzle temps dropped when the feed began. With the feed off and the fan on, the temps climbed to the set point again. With the fan off and the feed on, the temperatures held at the set point.

I used 100% fan speed a lot, and never had this problem. But, now it seems I can only use about 30% of my cooling fan speed or my nozzle temp drops and the nozzle clogs.

Has anyone had this experience with a cartridge heater? Is this a sign the heater is wearing out?

The heater core or the Thermistor can fail over time and cause the issues you are seeing. Usually, unless something got shorted out, it takes several years for one to wear out. Sometimes you get a bad one though. Thermistors usually get damaged by impact, or wires being torn out, etc. They last a fairly long time otherwise. Heater cores are basically a non light emitting incandescent light bulb core, so it will eventually melt itself someday just to repeated heat and cool cycles, but again, it usually takes years to get to that point.

If your fan is too powerful it can be overcooling the nozzle. Is it a stock 40mm fan and duct? or something larger? You might just be dealing with an unbalanced fan setup.

I experience the same thing when my fan is set higher than 60%. The hotend starts to drop in temperature. I suspect it may be a bad heater cartridge, but printing primarily with ABS it doesn’t affect many of my prints.