Do we need ABL (Auto Bed Leveling) devices anymore?



  • With the Duet3, does one need to run a bed leveling device or can one use the stall detection on the Z axis? I am in the middle of a swap to the Duet3 board in my Tevo Tornado and am contemplating if wiring up my BLTouch, now that I see that the RepRap firmware has implemented stall detection and one other feature, that the name of escapes at the moment, that can aid in deviceless bed detection on the Z axis.


  • Moderator

    Z axis stall detection probing is possible, but it's not usually practical for most printers, especially cartesian i3 styles printers due to usually using 2 Z drives, and the inherent flex of the bed and print head.

    https://forum.duet3d.com/topic/4772/motor-stall-detection-as-z-probe

    An old thread but should get you started.


  • administrators

    If your Z axis has a low steps/mm value (e.g. belt-driven Z axis) then stall detection isn't accurate enough, because at best it is reproducible to within 1 full motor step. If it has a high steps/mm, then the nozzle will apply a lot of force to the bed before the Z motor stalls, and the flexibility of the bed and the print carriage will reduce the accuracy. So the only way you would be likely to get it to work would be to have a Z steps/mm that is "just right" and very rigid mechanics.



  • @sevilnatas We've never needed auto bed levelling. Just build the printer so that the bed is flat, level, and stays that way. It really isn't difficult to do.



  • The closest thing I‘ve seen similar to what would be using Stall detection as a Z probe is the Smart Effector on a Delta. It is not the same, as it is based in some other phenomenon, but you effectively use the nozzle tip a sensor. Maybe one could design a carriage for a cartesian printer this this technology??

    BTW, buying the Smart Effector for my Delta was one of the best decisions I‘ve done (3D Printing related, that is).



  • @FelixH there is precision piezo orion that do the same thing as smart effector...i use it on my hypercube printer...and i also have 3 kossels with smart effectors on it...and the result is the same...very good stuff...(for my delta printers the smart effector along with magnetic arms and duet2 wifi was the best decision i made, on my hypercube the duet2 wifi and precision piezo orion v2 was the best decision i made)on my cartesian printer(prusa clone) i use bltouch...because is what was the best at that time, though if i had to make it again i 100% go with precision piezo...


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