3D Printing Prusa MK3 Printing Problem

Discussion in '3-D Printing and Related topics' started by gorillamotors, May 30, 2019.

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  1. May 30, 2019 #1

    gorillamotors

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    I just printed out these today using Amazon Basics Blue PLA. I have been getting a lot of these but it wasn't a problem because they were only prototypes for now. I have tried temps from 200-220C but have had no success. Any suggestions?
    Print 1.jpg Print 2.jpg
     
  2. May 30, 2019 #2

    manixFan

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    Does it make little popping noises? Almost looks like the PLA has absorbed a lot of moisture.

    Tony
     
  3. May 30, 2019 #3

    gorillamotors

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    Nope. Just took it out of the dryer before the print.
     
  4. May 30, 2019 #4

    mpitfield

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    It almost looks like it is under extruding. Have you calibrated your extruder?
     
  5. May 30, 2019 #5

    StuartL_UK

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    Is the tension on the extruder high enough? Looks like you might be slipping on the filament.
     
  6. May 30, 2019 #6

    cwbullet

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    I tightened mine and it fixed the problem on my Prusa. That looks like under extrusion to me.
     
  7. May 30, 2019 #7

    gorillamotors

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    Yea I put it under my microscope and it does look like under extrusion in certain areas. I have also tried tightening it up and still this happens. That is why I bought the Bondtech BMG-M extruder. It has both of the gears connected and turning and not just like the one in the Prusa. I am still working on designing the adapter for the Bondtech BMG-M/Mosquito Magnum combo. It is time consuming.
     
  8. Jun 3, 2019 #8

    gorillamotors

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    I think I might have found the problem. Along with the under extrusion problem above I was getting the problem of the extruder stopped extruding but continuing the print. I was reading a few of the other printer forums and it seems that the raspberry 3B+ and octoprint were the problems. So, I disconnected my 3B+ and used the SD card. I printed out six perfect PLA prints including five 6+ hour carbon PETG prints. I reconnected the 3B+ and the first 2 prints stopped extruding in the mid print. So, I am going back to using the SD card for now.
     
  9. Jun 3, 2019 #9

    cwbullet

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    That stinks. I have now has that Problem.
     
  10. Jun 3, 2019 #10

    gorillamotors

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    I just printed one yesterday with the Atomic Carbon PETG that I PMd you about. It took about 9 hours to print. Did not use the 3B+ but instead used the SD Card. It printed perfectly.
     
  11. Jun 3, 2019 #11

    gorillamotors

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    Just printed another 4+ hour print this morning without the 3B+. Printed perfectly. I used the exact same gcode files created by Simplify 3D to do one with the 3B+ and one with the SD Card.

    The forums are saying that it is most likely the cheap Chinese power supplies to the 3B+ that are causing the problems. I will be looking more into that today.
     
    Last edited: Jun 3, 2019
  12. Jun 4, 2019 #12

    cwbullet

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    I just print a set of 6mm thick bulkheads with the PETG CF from Atomic to test. Man, this stuff is tough.
     
  13. Jun 5, 2019 #13

    gorillamotors

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  14. Jun 5, 2019 #14

    liv3mind

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    I know Im a little late to this party, but I have found since about 2 updates ago with Prusa Slicer, that even printing via usb is hit or miss, I have been printing from SD card for about a week now without any more issues. Mine was stopping mid print, tripping the crash/filament sensor, even with it turned off on the printer, sometimes would stop printing, then continue in another spot on the bed, that was messy, and was having extruder/layering issues. Changed to SD only and it all went away. Hopefully they resolve it because I prefer to print via USB and have a dedicated machine for running my printer.
     
  15. Jul 2, 2019 #15

    gorillamotors

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    Does anyone know what the resistance is for the standard Prusa Mk3 hotend thermistor and 40W heater?
     
  16. Jul 11, 2019 #16

    gorillamotors

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    Has anyone had heat creep on a Prusa MK3? If so, how did you fix the problem?
     
  17. Jul 12, 2019 #17

    gorillamotors

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    What Prusa MK3 firmware version do you feel the most stable and with less problems?
     
  18. Jul 12, 2019 #18

    cwbullet

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    I use the most recent.
     
  19. Jul 12, 2019 #19

    gorillamotors

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    I just checked the heater block with a Fluke voltmeter/temp probe. I double checked the voltmeter with a Fluke IR laser temp gauge to make sure it was accurate.

    voltmeter IR laser
    hot coffee 62C 61.8C
    ice water 5C 4.8C

    So it was accurate.

    Prusa LCD reading (C) voltmeter (C)
    210 177
    230 191
    250 206
    280 229

    The resistance for a new 24v40w heater is 16.0 ohms and my current one is 14.9 ohms. Not enough to make that big of a discrepancy.

    Any suggestions?
     
  20. Jul 12, 2019 #20

    StuartL_UK

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    I don't think the resistance is linear with temperature so the resistance difference could indeed be the issue. I can't remember where and how this is calibrated but there will be an online temperature calibration guide somewhere which you should follow.
     
  21. Jul 12, 2019 #21

    gorillamotors

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    It is not resistance I measured. I measured temperature with a temp probe attached on the voltmeter.
     
  22. Jul 12, 2019 #22

    StuartL_UK

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    @gorillamotors You said: "The resistance for a new 24v40w heater is 16.0 ohms and my current one is 14.9 ohms. Not enough to make that big of a discrepancy." How did you measure this resistance? This discrepancy could be enough for the temperature discrepancy.
     
  23. Jul 12, 2019 #23

    gorillamotors

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    I talked to prusa and they said it would equate to a 36w heater instead of 40w. No big deal.
     
  24. Jul 12, 2019 #24

    StuartL_UK

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    Sorry, that was my error reading your message. I thought you meant that the temperature sensor was a different resistance when you clearly wrote that it was the heater. My sincerest apologies.
     
  25. Jul 12, 2019 #25

    gorillamotors

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    I am chatting with prusa right now. I am on my third tech. I spent about 4 hours with a total of 5 techs trying to get this problem resolved. In the end nothing was accomplished. Still have my under extrusion problem. PLA is problematic but anything else forget it. I hope this new bondtech/mosquito hotend will fix it.
     
    Last edited: Jul 12, 2019
  26. Jul 14, 2019 at 2:03 AM #26

    gorillamotors

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    Just checked 3 brand new thermistors and the resistance was around 94K ohms each. The thermistor tables in the firmware for this use tables based on 100K ohms. My thermistor in the printer measured 160K!! I think that might be the culprit. I will check.
     
  27. Jul 14, 2019 at 9:06 PM #27

    gorillamotors

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    Found my under extrusion problem. First was the thermistor. I had some Chinese thermistors that the resistance was 160K ohms and not around 100K ohms. The firmware uses #5 thermistor tables based on 100K ohms. This made the temps read 15-25C hotter than they actually were. Second was the heatbreak had a split at the neck junction. Fixed both of these plus I put some new thermal compound I just bought on the heatbreak (Thermal Grizzly Kryonaut Thermal Grease Paste). https://www.amazon.com/gp/product/B011F7W3LU/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&psc=1

    I just printed out 2 prints with the Atomic Carbon PETG and they were perfect.
     
    liv3mind and dhbarr like this.
  28. Jul 15, 2019 at 5:00 PM #28

    liv3mind

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    Always jazzy when you get PETG dialed, especially a exotic! glad you got it sorted, I just picked up a mk3s and a mk3s upgrade kit for my current mk3. my one machine only ever sees petg, but it was a boar to get dialed at first.
     

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