E3d Hotend Tuning and Settings

  • Hello Everyone,

    I'm running into a bit of an issue getting filament to move through the hot end. Right now I have my settings in the latest reprap firmware release:

    M305 P1 T100000 R4700 B4388 H0 L0
    M305 P2 T100000 R4700 B4388 H0 L0

    When using the webcontrol, the hot end temperature is set at 195c, but the filament isn't moving through the hot end smoothly at all, and bumping the heat up to 235c is still requiring a fair amount of force to push the filament out; for some hatchbox pla usually 195c should be plenty hot in my experience for the filament to come out molten and smooth. It's also coming out very curly. I've tried the manufacture B-value at 4267, from the manufacture datasheet, as well and I'm still getting similar results. I found the current B-value from the e3d wiki. Any thoughts would be greatly appreciated.


  • administrators

    What filament are you using? Have you extruded the exact same filament before?

    If you are unsure that the temperature is reading correctly, then one way to check is to feed a multimeter thermocouple probe into the hot end in place of the filament.

    Before I switched to a PT100 sensor, I was using B4388 with my E3DV6 hot end and thermistor, and printing PLA at 200 to 205C.

    Some modified PLA filaments need higher temperatures, for example PLA+ from rigidink needs 220-240C according to their web site.

  • Hello dc24,

    I'm using some hatchbox pla from amazon. The label states 190-210C. I think I might have to buy a thermocouple if I'm to check this temperature measurement. The filament still comes out of the very curled up to 260C. I have experience using this filament on a makerbot 5th gen so in my experience the way it's leaving the extruder is out of the ordinary. Is the benefit of using a PT100 sensor much greater than a typical thermistor?

  • administrators

    With a PT100 sensor the accuracy is much higher. However, for ordinary printing of PLA and ABS, a thermistor is normally adequate. It may be a few degrees off but you get used to what temperature your machine works best at for a given filament.

    If you want to check that the Duet is reading the thermistor resistance and computing the temperature accurately, you can substitute a fixed resistor for the thermistor and check the reading. For example, with B4388 a 220 ohm resistor should give a reading of 237C.

  • You may well have checked this already, but just to eliminate the non-electronic possibility: might you have a partial nozzle clog? Particularly your mention of the filament curling as it comes out of the nozzle makes me wonder.

  • FWIW - I run a lot of hatchbox pla and PETG, really like the stuff. Recently had the same issues you had, filament curling and prints failed at random spots, usually during repeated retraction which exacerbates issues with a partial clog. Had a heck of time getting it cleared out. Did cold pulls and nothing came out. What worked in the end was using the nozzle cleaning bits I have, running the temp around 230, pushing the nozzle cleaning bit it and then extruding plastic. Eventually a black piece of charred filament came out. Clogged cleared. No more curl. IMHO - The curl is an indicator of partial clog or damaged nozzle.

    If that would have failed, I was about to replace the thermistor with a PT100 anyway, so a tear down and cleaning was the next step.

  • Thanks for the responses.

    I connected the resistor and got about 239C with the B4388 setting. This seems within the correct range, so it's probably safe to assume the thermistor is correctly being read by the board. I tried pushing some filament through the nozzle at higher temperatures but still no good, it sounds like I may have to take the whole thing apart and take a look to see if there is any other type of clogging happening.

  • So I've tried cleaning it without tools and no luck. But I bought a chimera extruder so I loaded up the filament into the second head and gave it a go. The filament came out smoothly. Something must have jammed up the other nozzle during calibration at some point. I would say it's safe to conclude that this was a mechanical fault in the nozzle, nothing software or electrically related.

  • administrators

    Glad it's working. I guess it's not impossible that the thermistor in the other hot end is faulty.

Log in to reply