Titan Aero - Oozing PETG

Discussion in 'Titan' started by brad_b, Apr 26, 2018.

  1. brad_b

    brad_b Member

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    I have recently upgraded my CR-10 from a V6 clone Bowden setup to a Titan Aero direct drive. I exclusively print PETG with a .6 nozzle. With my previous setup, after trial and error to get the best settings I had very little issue with stringing and was overall very satisfied with the quality of my prints but I just couldn't leave well enough alone. I thought going to a direct drive setup would take it to the next level. It seems no matter what retraction setting I use It makes absolutely no difference. I have spent the last week and a half trying to sort this out and am now almost at the point of going back to my old setup. The stringing is not terrible but way worse than I had before. The biggest issue I have is at the end of a layer when it rapid moves back over previously printed line, it actually pulls plastic from the nozzle and when it starts the next layer it under extrudes for a short bit. I have tried a Z hop up to .5 but it makes no difference. The only thing I have done that seems to help is lowering the nozzle temp. I was printing at 244 degrees with the old setup and I am now down to 230, anything below that and I start having bonding issues. I have tried retractions from .1 to 2 mm and retract speeds from 8 to 85 with no difference. Any ideas on why this is happening? It does seem like it takes longer now for the nozzle to heat up than it did on my previous setup. Below is a list of setup.

    Marlin 1.1.8 firmware
    Thermistor choice #5 in firmware
    Auto tune to get correct PID settings
    Linear Advance disabled
    Esteps calibrated and set to 401.86
    Extruder Max Acceleration 1500
    Extruder Retract Acceleration 800
    Max E jerk 10

    IMG_2338.JPG
     
  2. Nik

    Nik Member

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    Have you done a PID autotune and tried printing at 240? With PETG i've found that it's better to use a higher temperature because it likes to string and clump on the nozzle when colder. Fan would turn on only during bridging moves because its tendency to string up helps there. You can also try doing a temperature tower to see what works best.
     
  3. brad_b

    brad_b Member

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    I have tried temps from 226 - 248 with around 230 being the best. I have done autotune several time at different temps and the numbers are all over the place. Is it common for values to be so inconsistent?
    M301 P30.07 I2.53 D89.29; PID Values for 236 deg 4/14/18
    M301 P23.86 I1.89 D75.25; PID Values for 242 deg 4/17/18
    M301 P24.85 I1.82 D84.98; PID Values for 205 deg 4/18/18
    M301 P27.77 I2.13 D90.47; PID Values for 234 deg 4/24/18
    M301 P22.87 I1.58 D82.90; PID Values for 230 deg 4/24/18
    M301 P26.57 I1.91 D92.48; PID Values for 226 deg 4/24/18
    M301 P25.90 I1.95 D85.92; PID Values for 238 deg 4/26/18
    M301 P29.46 I2.19 D98.94; PID Values for 236 deg 4/26/18
     
  4. Nik

    Nik Member

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    Why are you using such odd numbers for the temperatures? I'm guessing the differing PID values have to do with using different temperatures for the Autotune. Normally you'd be setting it to a typical use-case scenario like 200C, if you're working with PLA. Also did you remember to save the settings to EEPROM or recompile the firmware?
     
  5. brad_b

    brad_b Member

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    These are autotune values for each specific temp. I don't store PID values in EEPROM, I just use M301 like shown above in my start code.
     
  6. Nik

    Nik Member

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    Just noticed you mentioned trying retract disances between .1 to 2 mm - that seems small, i use 2mm as a minimum. Cura recommends 4.5mm. In Slic3r i have also set "Lift Z" to zero and retraction speed to 40mm/s.
     
  7. Phaedrux

    Phaedrux Member

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    4.5 mm retraction distance on the aero would likely lead to clogs.

    For PETG and in general I have had best luck using 0.8mm distance and very fast retractions with slower unretracts. 200mm/s with high acceleration and jerk and 30mm/s unretract. Ive also found pressure advance to help a bit with oozing.

    Another thing that helped a lot was usinrg a very high first layer height. 0.4mm with 0.4 line width and a slow speed 25mm/s laid down nice first layers. Anything else tended to gum up a bit on the nozzle which made stringing during the print no matter what.

    I am also ysing very fast travel speeds. 350mm/s with 6000 acceleration and 40 jerk.

    Temp usually 240-245.

    No stringing at all with these settings.
     

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