Inaccurate temp measurement?



  • Since installing the Duet Wifi, I am noticing that the layers in my prints aren't adhering very well.
    It's not bad, but I am seeing separation here and there, and each layer is very noticeable to the eye, vs nice and smooth and having to squint to see each line.
    I pulled a print off the build plate earlier and it cracked along a layer line.

    I have been printing with PLA+ since commissioning my new printer.
    The recommended temp per the manufacturer is 205-225C.
    I have upped it to 230 and it is getting better but I just feel I shouldn't have to crank it so high.
    I have printed this same stuff on my old Prusa clone and it came out beautiful and quite strong.
    So much so I have opted to use it over PETG because it's easy to print like regular PLA.

    I am using an E3DV6 and the new style temp cartridge.
    When the nozzle is cool it matches room temperature.
    I have tried comparing the temp displayed on DWC to a reading from an IR heat gun I have, but the heat gun fails to give me a logical temp.
    It says the nozzle is 60C when DWC says it's 220C.
    I believe the IR gun is having trouble reading something so small.

    I have checked the config settings and they match with what I found online that should match the E3D cartridge.
    But just in case will someone verify I have it set correctly?

    [[language]]
    ; Heaters
    M143 S260 ; Set maximum heater temperature to 260C
    M301 H0 S1.00 P10 I0.1 D200 T0.4 W180 B30 ; Use PID on bed heater (may require further tuning)
    M305 P0 T100000 B4138 C0 R4700 ; Set thermistor + ADC parameters for heater 0
    M305 P1 T100000 B4725 C7.060000e-8 R4700 ; Set thermistor + ADC parameters for heater 1
    
    

    If it is correct, then I guess I should just ignore the recommended temp and bump it up higher?
    I just feel like hotter than 230C would be way too much.

    Thanks in advance.



  • What does the temp say when no heat is on, does it match room temp?



  • I am using an E3DV6 and the new style temp cartridge.
    When the nozzle is cool it matches room temperature.

    Both the nozzle and bed temp at idle are 24C.
    Another reason I am stumped because it matches the bed temp.



  • Sounds like your settings for it are correct. I missed that part about room temp in the origional post. You shouldnt have to go so high in temp. Is there a part blower turned on? also are your steps/mm calculated correctly for Z



  • Yes, I have a cooling fan that I set at 100%.
    This is the same speed I have on my other printer.
    Maybe set it for 50% and try that?

    I am quite confident in my step settings in config.g.
    I put a ruler on the bed and measured the movement of the nozzle compared to the distance I moved X and Y. I adjusted accordingly. I stood a ruler up vertical to measure the bed(Z) movement and have it nailed down the same way.
    I did the extruder the same way, by measuring the amount of filament it moved.

    I'll try a slower fan speed and report back. I don't know why I didn't think of that before.
    Thank you sir!



  • Whitewolf,

    The slower fan didn't help enough to say that is the culprit, but it hit me when thinking about your question if the Z steps were accurate. Even though I measured the bed movement, I can't really nail down a deadly accurate measurement with the naked eye. Especially since we're talking .2mm, so I backed the steps down from 400 to 399.9 and that was the ticket. I am going to print a test cube and measure Z to see if I can't bring it down once more because I think it could still be a little better.
    Thanks so much for the response. You turned me into a direction I didn't even consider!



  • Lowering the value of the Z travel helped a lot but I still wasn't satisfied with how my prints were turning out.
    I was getting blobs, especially in the corners.
    Even though I tried changing settings in my slicer (Simplify3D), sometimes to the extreme just to see the result, I could never get a nice clean print.

    So I went for broke and started raising the heater temp.
    I found that 240C apparently the sweet spot.
    Each layer is nice and shiny now, instead of the dull, dry look I was getting with the recommended temps.
    And the blobs in the corners disappeared. One audible piece of evidence was my extruder stepper would pop on long lines. I am printing at 80mm/s. It has stopped doing that.
    I attributed the blobs in the corners to maybe pressure build up from the stepper trying to push the filament through the nozzle with it not hot enough, and it oozing out even though it was retracting.

    So with all that, I am assuming that the manufacturers temp recommendations are way off, or my temp reading is inaccurate.

    For reference the recommended max temp is 225C. eSun PLA+ filament.

    Also it is of note that I tried printing PETG which I have always had good luck with and the filament bent and started coming out the side of the feeder right at the pulley. I gave up and stuck the PLA+ back in and started experimenting with the temps.

    Any ideas? What say you?





  • @number40fan:

    https://www.duet3d.com/forum/thread.php?id=1138#p11089

    Use 4388 for B.

    If I read this thread correctly, 4388 is used when using older firmware.
    1.17 or higher you would use 4725.
    The wiki has been updated to this as well.

    Did I misunderstand?



  • Sorry, I didn't go through the Wiki as much as I should have. Was just having under temp issues and found the thread I linked to. Switched those numbers around, original was something in the high 3000's, and my problem was fixed.



  • Fixing the blobs isnt the heat… just because it works doesnt mean its the right thing to do.

    What is your pressure advance settings, does exactly 100mm of filament come out when you extrude with hotend detached?

    You really need to get a caliper, they can be found at harbor freight for cheap.


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