Tiny layer shifts. Where to start?

Discussion in 'Getting Started' started by Nibbels, Aug 5, 2020.

  1. Nibbels

    Nibbels Well-Known Member

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    Good evening.

    I did not want to write much this evening. So I made a unlisted youtube video.
    The main problem is not the broken priming tower :D
    It is the tiny layer shifts. I guess I know that someone talked about such here but I cannot find the post.



    Who experiences/experienced the same (or worse)?
    Screenshot_18.jpg
    Can anyone share a possible fix that helped him?
    Where should I start to look for the cause of this?

    Thank you
     
  2. 1013D

    1013D Active Member

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    tighten the belts...this fixed many print anomalies.
    Also check to see if the motor belt pulleys are rubbing the side of the belt very hard. had this on one motor and it caused strange things.

    Other thing I did was add a washer to the tool changing spring on the shaft. this increased the holding power a little.
     
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  3. jschall

    jschall Member

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    Your bed screws might be too loose.
     
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  4. dc42

    dc42 Well-Known Member

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    if they are caused by skipped steps, the amount of shift will always be a multiple of 4 full steps.
     
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  5. Nibbels

    Nibbels Well-Known Member

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    Thank you so much for your replies!

    Ok, one problem is the bed! I did not see it, it would have been easy to check. Totally loose.

    2cm before finish my hemera tool dropped. ^^
    The bed was not the only cause. I will check the belts this evening. Maybe the docks are not aligned 100% perfect orelse the tool grabber / coupler is a problem again.
     
  6. SABRE

    SABRE New Member

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    I am slowly but surely getting start with my new ToolChanger (it’s an amazing beast). I am having similar issues as described by @Nibbels. There are significant layer shifts at completely random places.

    My setup is the following:
    • Duet 3 6HC
    • Extruder: TitanAero
    I have already reduced the acceleration to 1000mm/s^2, maximum speed to 14400mm/min and i am running it in in stealthchop mode. Assuming that the relatively heavy tool head might cause an overshoot.

    Mechanically there is nothing loose, i checked all fasteners. I increased the too clamping strength by shimming the spring by 0.25mm.

    Has anyone got any advice?
     
  7. Joe Pomo

    Joe Pomo Well-Known Member

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    I had weird extrusion irregularities and found that my hemera mounting parts were loose.
     
  8. John Meacham

    John Meacham Well-Known Member

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    I had something similar and found out that only while hot my hot ends had a little play in them and the tip would be to get pushed around by half a mm or so, but it felt perfectly solid while cold. I rebult it and cleaned out the head and did a hot tightening at a blistering 290 and didn't have the issue any more. Im not sure exactly what the issue was but my theory is my initial hot tightening didn't fully take and a bit of plastic was wedged in there that only allowed movement while it was softened. After a lot of frustration with inconsistent calibrations I found it by bringing everything up to a bit past print temp and poking at it from every angle with a stick until i felt something that had a little give that shouldnt have.
     

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