How to properly level the bed ?

Discussion in 'Calibration, Help, and Troubleshooting' started by Falc.be, Apr 13, 2016.

  1. Falc.be

    Falc.be Well-Known Member

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    After doing some large prints with a large first layer (in this case the big bottom plate for the open rc F1) i found that there where bed adhesion problems in some area's, in particular when going to the right
    After doing some bed leveling several times and not getting the problem fixed I wrote down the Z-axis offset values and then got pretty worried:

    2,800 2.874 2.824
    3.149 3.374 3.350
    3.274 3.584 3.524


    These results are pretty consistant after several bed leveling procedures so this is not a Z-axis issue

    Mechanically speaking the bed is not even close to being level and I dont understand how I can fix that since there are no adjustment screws.

    One thing I can think off are high precision shims but they cost allot
     
    #1 Falc.be, Apr 13, 2016
    Last edited: Apr 13, 2016
  2. Kick2box

    Kick2box Well-Known Member

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    Like that:
    IMG_0379.JPG
    If the upper screw is fixed, nothing can move any more. It's written somewhere in the manual too.
     
  3. Miasmictruth

    Miasmictruth Well-Known Member

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  4. Kanedias

    Kanedias Well-Known Member

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    A carriage for a dial indicator would be handy to have. Hmm.
     
  5. Falc.be

    Falc.be Well-Known Member

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    Actually it would be pretty easy to do if you create a new bearing clamp with a mounting point

    you can easily take it on and off again.

    as for myself, I am looking to order 0.05 to 0.2 mm shims to level the bed.

    I know this things from my RC days, they are used to setup ride height
     
  6. Old_Tafr

    Old_Tafr Well-Known Member

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    Are you saying that if the screw in the top is tight, but the spacer below isn't screwed in fully as shown in the photo that it is stable?
     
  7. PsyVision

    PsyVision Moderator
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    Yes, that's how I adjust mine. Undo the top screw, twist the spacer to adjust the height of it, then tighten the top screw.
     
    Razar likes this.
  8. Ray

    Ray Well-Known Member

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    I did wonder if this was how to do it, my concern is that the top screw and the spacer aren't exactly an engineered/tight fit and so there could be possible movement. Especially when this design was used instead of springs because of possible movement.
     
  9. PsyVision

    PsyVision Moderator
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    I've had no such issue. Getting into the realms of idealism and theory than whether it actually has a real effect. If anything, the looseness of the screw in the bed that the standoff screws into is more of an issue than whether you've done the top screw up tight enough.
     
  10. Ray

    Ray Well-Known Member

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    PsyVision, when my bed moved down on occasions its makes a high pitched squeal sound, I remember seeing a BB video on YouTube and that did it also, is that ok do you think? both the corner rods and the lead screws are coated in white lithium grease.
     
  11. PsyVision

    PsyVision Moderator
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    When assembling, without lead screws it should move without much sound and definitely no squeaking.

    With lead screws, no LG and being operated by the motors mine did make some noise occasionally.

    With LG it shouldn't squeal at all in my view.
     
  12. Stefan

    Stefan Well-Known Member

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    It may be a stupid assumption, but is that not why we do this mesh bed level thing? So we do not have to have a 100% level bed?

    But these values:
    2,800 2.874 2.824
    3.149 3.374 3.350
    3.274 3.584 3.524

    they look like the glass has a bumb in the middel on X axis...
     
  13. PsyVision

    PsyVision Moderator
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    Definitely Stefan, but its good to have a roughly level bed already tho as there will need to be even less compensation done by the z motors (less movement involved)
     
  14. Alex9779

    Alex9779 Moderator
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    I have the same feeling but I think it is the weight of the carriage bending the rods in the middle. I wanna design a holder for my dial gauge, then remove the carriage and use the light one with only the gauge to level as good a possible as someone described above. Then I will see what it is. The glass or the rods...
     
  15. Old_Tafr

    Old_Tafr Well-Known Member

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    For shims use pieces cut from an Aluminium drinks can. Cut with tin snips or similar.
     
  16. Old_Tafr

    Old_Tafr Well-Known Member

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    An alternative approach would be to...

    A make a "measuring stick" use a thin piece of bamboo approx 11" long (27 to 28 cm in new money) with a round head screw screwed in half of its length in each end.

    Use the sticks as a fixed length gauge between the glass plate and the underneath of one of the two X-Carriage smooth rods.

    Just drop the Z axis down to the length of the measuring stick, then adjust the screws in it to the distance between a smooth rod and the glass plate. Move the rod to various places on the glass plate to check the distance and adjust the bed left right using the Z motors (release the steppers via the front panel) screwed rods. so that all distances are the same.

    Measure between the rear rod as well as the front rod. Measuring at the extreme most ends left and right gives the best accuracy. You could also move the X-Carriage in the Y direction and make more measurements this way.

    If you are lucky the distance to the rear rod is the same as the front rod, if not you will have to adjust the pillars holding the glass plate, say just at the rear.

    The checking the distance between the glass plate and front and rear smooth rods took me a couple of minutes.

    After adjusting the front to back slope then the mesh leveling (the 9 locations via the front panel) will do the fine tuning.

    I started with all pillars supporting the glass plate screwed completely down, although a slight raising of the pillars would probably be better.

    An alternative would be to measure just from the front smooth (X-Carriage) rod and once the left right adjustment is right then just move the carriage from the front to the back and make the distance equal using the pillars at the front or back of the glass plate.

    Like any measurement this depends on a reference which assuming the X-Carriage smooth rods are parallel is in my case the front rod.
     
    #16 Old_Tafr, Apr 14, 2016
    Last edited: Apr 14, 2016
  17. Kick2box

    Kick2box Well-Known Member

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    Thats the purpose of the nylock nut here:
    http://wiki.e3d-online.com/wiki/File:Lock_nut.jpg
     
    Old_Tafr likes this.
  18. Old_Tafr

    Old_Tafr Well-Known Member

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  19. Falc.be

    Falc.be Well-Known Member

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    Mine is supe
    how thick are those ?
     
  20. Miasmictruth

    Miasmictruth Well-Known Member

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    Me too
     

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