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Partially Solved Test print failed.

Discussion in 'Troubleshooting' started by joea, Nov 17, 2019.

  1. joea

    joea Member

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    Trying a test print of "Car Grille Fastener" found on thingiverse, I had a failure.

    Part of it is attributable to the "nut" part not staying attached to the bed, as I found it off to the side when I checked on progress, but also noticed it has gotten "thready" for several layers.

    Also found it odd that there was a thing "thread" around each object with seemed to serve no purpose. I will venture a guess this is supposed to be part of this "skirt" mavens speak about, but . . . I dunno.

    The "calibration circle" had the same thin thread surrounding it and now, looking over the settings in MC again, it appears this is normal when "raft" is not selected and I should probably enable "raft" to assist with adhesion.

    I would appreciate any input on this and as to why the "nut" part of the print became "thready". Could that be it was a bit loose and continued to get looser?

    Pictures attached.

    I did have to fiddle with the Z Offset ending up at 1.9mm. It was at "zero" after installing the firmware. I understood the default was 1mm. This eliminated the grinding of the filament, but was discovered too late ot prevent some marring of the bed surface.
     

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  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  3. joea

    joea Member

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    Thanks, I had seen that, but it is clearer now.

    Question. How does "auto leveling" do it's thing? I have watched the gyrations before each print and have an inkling, but, need to clarify some things. How does the firmware decide where Z "zero" is? by lowering until one of the Z axis limits is actuated? Actuate each and work with that, or an average of the two. Or three, if it also tests with carriage centered left to right?

    Then, does it use the Z Offset to place the nozzle above the bed?. Further to that, if I add painters tape or some other adhesion promoter, does the zeroing or "self leveling" make that surface the new zero height?

    I hope that was clear.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes. Exactly.

    Again, exactly. The nozzle will go to Z HOME + Z offset.
    Technically it is the "calculated" level plane that it uses the sensed points to generate that then gets the Z offset applied to, but you get the idea. It probes 9 points, uses math to generate a flat plane that intersects all 9 points and then applies the Z offset to that.*

    As long as the probe that senses the bed can "see" the new surface it will use that as the bed so it will not adversely affect you. The way the R1 does this it should be fine. The R2/C2 uses an IR sensor that requires a dark surface...



    *in the case of mesh or UBL or MESH the bed is subdivided into smaller MESH sections and those then get a plane calculated for them and the offsets applied. MESH/UBL is far more accurate if your bed is actually deformed.
     
    #4 mark tomlinson, Nov 17, 2019
    Last edited: Nov 17, 2019
    Geof likes this.

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