Hot End Not Hot Enough

Thanks for reading.

My Lulzbot Mini has suddenly stopped getting hot enough to extrude. I had not made any changes before it started happening. The nozzle only gets to about 70C according to my IR thermometer.

The resistance of the thermistor is 120K and the heater’s resistance is 20. I’ve updated the firmware. I checked the wiring for continuity and it’s all normal. Doesn’t rule out intermittent connections obviously so the next thing I will try is running new wires. If anyone out there has any thoughts on this I’m all ears.

Another maybe important detail I left out, Cura shows that the temperature of the hot end is 210c but it’s clearly a lot less than that.

Try manually sending gcode commands to see if the heater heats up.
If not, replacement thermistor / hot end isn’t that expensive.

Thanks for your suggestion. It actually did heat up using the gcode command.

I already ordered a new thermistor and heater cartridge at the recommendation of support. It was only around $20 but now I wonder if it is some other problem.

Sounds like the gcode getting sent is not what you are expecting.
Check the gcode file getting sent and the cura settings.

Or try another slicer - I’ve been using superslicer and it’s alright.
Could also try prusa slicer or the updated version of Cura.

Thank you, I will try all of that (though checking the gcode file getting sent is a little above my skill level).

Slice something small like a 5x5x5mm cube and if it shows the same temperature issue, then upload the .gcode file here.

I installed the updated version of Cura and now it’s working fine. This has happened before though where it would heat fine then stop again. I’ll keep printing til something changes!

The GCODE is readable as a text file. You’re looking for M104 (heat to temp) and M109 (wait until specified temp is reached) commands.

Also, you said you were using an IR thermometer, those things are really hard to get to focus on the tip, so the 70C may be the average temperature that is including the heatsink and other parts - not just the hot end.

Yes, I think you’re right. I checked it again when it started working and it was only about 10 degrees hotter.