capacitive Z levelling?

Discussion in 'BigBox General Chat' started by R Design, Oct 23, 2016.

  1. R Design

    R Design Well-Known Member

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    In this interview ultimaker CTO says UM 3 is using Capacitive (not Inductive / IR etc.) sensor for Z levelling.



    Anyone know anything about that?

    A few other things too.... like they use PEEK in the hotend!
     
  2. Kanedias

    Kanedias Well-Known Member

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    Capacitive sensors are what's used in those lamps that you can touch the base to turn on, maybe it's something like that. :D

    I wish they'd went for a bit bigger on the bed dimensions but the cartridge idea is great. Why swap nozzles when you can sell people whole extra hot ends.
     
  3. dc42

    dc42 Well-Known Member

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    Capacitive sensors are great for detecting whether an object is present or not. When used to measure distance accurately, they work best at very close range to a conductive target. So with the same sort of bed construction that inductive sensors work well with. If you try to use them with glass print beds, they tend to be sensitive to temperature and moisture. What type of bed does the Ultimaker have?
     
  4. R Design

    R Design Well-Known Member

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    That's the thing. It says "heated glass bed" in the spec sheet for the UM3.

    I'm guessing that's glass sheet over aluminium bed.

    EDIT: in minute 1-2 of the following video they talk about levelling

    If it's an aluminium bed under the glass sheet, it's gotten a lot thinner!

     
    #4 R Design, Oct 23, 2016
    Last edited: Oct 23, 2016
  5. Henry feldman

    Henry feldman Well-Known Member

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    Doesn't the new Prusa i3 Mk2 use that for it's mesh leveling? They also use for skew detection if I remember the review in Tom's video...
     
  6. R Design

    R Design Well-Known Member

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  7. Henry feldman

    Henry feldman Well-Known Member

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    Although if you look at this video, they seem to be doing some multi-pass scanning over each of the 9 points:

     
  8. R Design

    R Design Well-Known Member

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    Somewhere I read that the Prusa's PCB bed has been "specially modified" so that it will work with Induction. No idea what they have done. Perhaps enormous Vias (cross-board metallic connections)?

    The multi-pass behaviour you observe is just their mesh bed levelling process. Of course that's what we want to achieve.
     
  9. Henry feldman

    Henry feldman Well-Known Member

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    Those look like active coils rather than passive metallic objects. Easy to generate a specific shaped magnetic field and then sense it.
     
  10. R Design

    R Design Well-Known Member

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    True. That's how inductive sensors work.

    Want to know what's the capacitive setup on the Ultimaker.
     
  11. Henry feldman

    Henry feldman Well-Known Member

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    Induction can be used to either detect a passive lump of conductive material (say iron) or an active magnetic field. So you could do it multiple ways (put little lumps of iron under the bed, put magnets under the bed, generate magnetic field with a coil).
     
  12. R Design

    R Design Well-Known Member

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    I know well a CNC that uses lumps of metal as endstops for bed travel to inductive sensors.

    But in our case the interest is to be able to detect nothing less than the Surface of the bed - and discern it's distance from the sensor. Want to know more what UM are doing. ;)
     
  13. PsyVision

    PsyVision Moderator
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    You're just going to have to buy a UM3 and then tell us...
     
  14. Alex9779

    Alex9779 Moderator
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    @PsyVision bad idea... tell him to buy two, send one to you and one to me and we will check it out :D
     
    Thorvinus and mike01hu like this.

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