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Solved Z-ribbing related question + coupler replacement

Discussion in 'Troubleshooting' started by CoenB, Jul 19, 2015.

  1. CoenB

    CoenB Member

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    Alright, I finally had some time to perform (what I thought would be) finishing touches. Unfortunately, that is not the case.

    I started by switching out the couplers and rods one by one. I noticed that the rods were a bit loose in the couplers, so I put a few layers of teflon tape around the rods. After that, they fitted perfectly.

    I reinstalled everything and gave it a shot. First I tested the movement of all axis by moving all parts by hand. Nothing seemed obstructed, so I tried manually moving it with the Controller. No problems there as well. I fired up the PLA preset and started a 15mm_cube print. To my knowledge, nothing has to be changed in the Repetier/Slic3r software, so I didn't. I did check the presets to be sure though.

    When the printer started the 15_mm cube, the Z-axis made a weird sound. I checked and it seemed that the steppers stopped moving, it made a kind of jamming sound. I pressed the emergency button on the controller.

    I thought that the sound might be caused by the couplers. My idea was that they were spinning freely on the motor shaft of the Z-steppers, I concluded that because I noticed it was kinda loose while tightening the couplers on the motor shafts. So I disassembled everything and applied a layer of teflon on the motor shaft of both Z-steppers. Assembled it and tried printing again. Still the same problem.

    I suspect it has something to do with the software, as the problem does not occur when I move the Z-axis with the Controller.
    Check this video for a explanation:


    The things I changed in the 3_14_14 Marlin firmware, under Configuration.h, were:

    #define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,2560,723.38} // default steps per unit X, Y, Z and extruder for RoBo 3D R1
    #define HEATER_0_MAXTEMP 250 //robo​

    And for the presets (while I was there, saved me some time via this route instead of via the Controller itself):
    #define PLA_PREHEAT_HOTEND_TEMP 210
    #define PLA_PREHEAT_HPB_TEMP 60
    #define PLA_PREHEAT_FAN_SPEED 255 // Insert Value between 0 and 255

    #define ABS_PREHEAT_HOTEND_TEMP 235
    #define ABS_PREHEAT_HPB_TEMP 100
    #define ABS_PREHEAT_FAN_SPEED 0 // Insert Value between 0 and 255​

    Seems as if that should not be a real cause for this problem, except for the #define DEFAULT_AXIS_STEPS_PER_UNIT.

    Any thoughts? To my knowledge I assembled everything correct and nothing seems to have been broken while performing these 'upgrades'.
     
  2. CoenB

    CoenB Member

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  3. Mike Kelly

    Mike Kelly Volunteer

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    Some thoughts:

    Bad stepper motor
    Stepper drive undercurrented
    Stepper driver overheating
    stiction in the rods needing lubrication
     
  4. CoenB

    CoenB Member

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    Well, nothing changed on the stepper side. So bad stepper motor and drive undercurrented are options that I think are unlikely. But then again, the sound seems to be coming from the stepper itself... I don't know what to make of this.

    That leaves overheating and the lubrication. Overheating also seems a bit odd to me, as (again) nothing has changed while switching from the imperial to the metric rods (besides the rods).

    I shall try the lubrication option, as I think that is the most logical of all.

    Jeez, fix one problem and create a bigger one....
     
  5. Mike Kelly

    Mike Kelly Volunteer

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    You probably need to increase the current running to the stepper drivers if you went from 5/16" to M8
     
  6. CoenB

    CoenB Member

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    Aha, I did not know that. Is there a topic somewhere that explains how to do that?
     
  7. Mike Kelly

    Mike Kelly Volunteer

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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  9. Mike Kelly

    Mike Kelly Volunteer

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    hmm I don't think that boots industries link is working (for me at least?)
     
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    weird. Pulls right up for me.
     
    WheresWaldo likes this.
  11. CoenB

    CoenB Member

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    Yey. That fixed it. At the same time I got a reply from you guys, I also got a reply from Jerry at Robo with the same information. So following up on these tips, I turned the screw about 1/8th of a turn clockwise. And tadaa, no more problems.

    After that I started a 15mm_cube (2x) print again at 0.3mm, followed by a 0.1mm print. Results:

    1= 0.3mm with imperial rods
    2= 0.3mm with metric rods
    3= 0.1mm with metric rods

    [​IMG]

    As you can see, there is still some imperfection in the surface of the layer buildup. With 0.1mm looking worse than 0.3mm.

    But from the front, oh boy, this got me excited:

    [​IMG]

    Just look at that surface. Again 0.3mm looking better than 0.1mm.

    And a picture just to see the decrease in Z-ribbing when you look at the edges:

    [​IMG]

    There still appears to be a little bit of an uneven surface / layer buildup. Noticeable at 0.1mm on the last image. I think this now is a matter of fine tuning the software side (flowrate etc.). And I shall install the ball bearings as well later on.

    But still, way way way better than before. I am a happy man. This has gotten me excited again to print some stuff. If only now my second printer came back from repairs, I can really start spewing out 3D objects.

    Thank you all very much, again, for helping me figure out this problem from the beginning.

    Kind regards,
    Coen
     
    mark tomlinson likes this.

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