BLTouch Config



  • Just re-wired my Wanhao Duplicator i3 Plus to use my Duet Wifi board and a BLTouch sensor.
    Things seem to be going fine so far which is great.

    I'm configuring my BLTouch sensor and I'm following the guide on https://betrue3d.dk/bltouch-on-duet-wifi-configuratio-and-usage/ . I'm at the point where I've adjusted my homing scripts to use G30. I ran through a few times and manually adjusted my screws to get it fairly level. Looks like the important bit is then making sure the height map is loaded in my sliced Gcode, correct?

    Now I'm at the point where the author begins talking about multiple Z motors which my printer does have... It seems like this is trying to have the printer do some auto bed leveling by individually controlling each Z motor? Is that really necessary? It feels like this section got tacked on without extra detail of the previous bits. If it is necessary, does anyone have a clearer guide on doing this for a "tower" style printer ie bed moves along y and head moves for x and z?


  • Moderator

    @rschlachter said in BLTouch Config:

    It seems like this is trying to have the printer do some auto bed leveling by individually controlling each Z motor?

    https://duet3d.dozuki.com/Wiki/Bed_levelling_using_multiple_independent_Z_motors

    This is usually used in an i3 style cartesian where the X axis gantry holds the print carriage with 1 Z motor on either end. By probing either side of the bed, the X gantry tilt can be corrected so that it is parallel with the bed. It's also used in corexy style printers where the bed is supported by 3 individual Z motors and allows for the entire bed surface plane to be adjust to be parallel with both the X and Y axis.

    It's not absolutely necessary if your build doesn't suffer from tilt. It also requires some mechanical compliance in either the X gantry or the bed mount to allow for the needed adjustment movements. So it kind of needs to be in the design plan from the start for best results without binding. That said, most i3 designs are supple enough to allow for some small amount of adjustment, and is functional as long as you get the gantry aligned manually to start with. Then it can cope with the small amount of difference that would result from normal power cycle positional changes to the two Z motors.



  • Thanks for the link and explanation. That's a really cool feature, but I'm not sure if It's something I want to implement yet. My end goal here is to get things back to working well, then to tear it apart again and convert it to the ReDuplicator.


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