Hot end auto-tuning keeps failing



  • I have tried the following:
    Warning: Auto tune of heater 1 failed due to bad curve fit (G=3862.3, tc=234.1, td=4.7)
    5:08:02 PM Auto tune phase 3, peak temperature was 319.1
    5:07:51 PM Auto tune phase 2, heater off
    5:07:28 PM Auto tune phase 1, heater on
    5:07:22 PM M303 H1 S260
    Auto tuning heater 1 using target temperature 260.0°C and PWM 1.00 - do not leave printer unattended

    Warning: Auto tune of heater 1 failed due to bad curve fit (G=4150.7, tc=238.4, td=4.0)
    5:30:39 PM Auto tune phase 3, peak temperature was 296.3
    5:30:29 PM Auto tune phase 2, heater off
    5:30:07 PM Auto tune phase 1, heater on
    5:30:02 PM M303 H1 S245 ;
    Auto tuning heater 1 using target temperature 245.0°C and PWM 1.00 - do not leave printer unattended

    Warning: Auto tune of heater 1 failed due to bad curve fit (G=4516.7, tc=229.2, td=3.5)
    5:47:32 PM Auto tune phase 3, peak temperature was 263.8
    5:47:21 PM Auto tune phase 2, heater off
    5:47:03 PM Auto tune phase 1, heater on
    5:46:57 PM M303 H1 S210;
    Auto tuning heater 1 using target temperature 210.0°C and PWM 1.00 - do not leave printer unattended

    5:56:37 PM M303
    Heater 1 tuning failed

    All of the temps I have tried have 3 different temps with the same result.
    Am I doing something wrong?



  • It looks like what happens when someone uses a 12volt heater cartridge with a 24volt power supply. I have seen a few people do that with their Ender 3 printers since they didn't know it was a 24volt system and they purchased what is used on a CR-10 printer which is 12 volts.



  • Makes sense. It is getting to temp really really fast. So if I have a 24V PSU how do I get 12V to the hotend? I have a 24V to 12V converter but I wouldn't think it could takes 4 or so amps. Do I need a 24V cartridge?



  • Just get 24 volt heaters - they are cheap.

    Frederick



  • Just ordered one. Thanks for the help.



  • Does the temperature profile look rough? I've had that error from a failing thermistor. I imagine it could also be made from bad connections making intermittent fluctuations in temperature.



  • It curve starts out vertical because of the 12V heater cartridge. Also, Overshoots about 30 degs. because the voltage is doubled. Found a 24V cartridge in my box of misc parts. The curve is more gradual on heating and now I get a different warning.

    10:43:35 AM Warning: Heater 1 appears to be over-powered. If left on at full power, its temperature is predicted to reach 514C.
    Auto tune heater 1 completed in 226 sec
    Use M307 H1 to see the result, or M500 to save the result in config-override.g
    10:41:14 AM Auto tune phase 3, peak temperature was 202.5
    10:41:07 AM Auto tune phase 2, heater off
    10:39:55 AM Auto tune phase 1, heater on
    10:39:49 AM M303 H1 S195;
    Auto tuning heater 1 using target temperature 195.0°C and PWM 1.00 - do not leave printer unattended



  • @twistedfab13 That over-powered warning is an informational warning.



  • Yah, It seems to be working now. Save using an M500. Now trying to do a first print. The Z says 0.3 but the nozzle is a good 5 mm above.





  • Yah figured it out. Was doing the mesh compensation. When I looked at the mesh it was really bad and all over the place. Long story short the fan cable was too close to the probe and it was registering all the time. LOL. Quick fix and now the test print it laying down correctly.

    Thanks for the help!!


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