Is BL Touch the best option?



  • So I am running a duet wifi (and I love it) but I have considered adding ABL to my setup. Just curious is bl touch seems to be the best option?
    I have a modded CR 10 which includes a Nova hot end with a duet board. Otherwise its fairly stock (i guess a new extruder too).
    Just curious which kit to buy, or what I need to buy. It seems there are TONS of links on amazon to large kits, small kits, etc... Ive never bought a bl touch, so Im not sure how much of said kit I would need???
    Thank you guys/gals.



  • be aware that there are a lot of clones around and they are not good enough.
    normally places that sell duets also sell genuine bltouch.
    the kits are mainly mounts that that you can print yourself, or adapter for other boards (not for duet).

    depending on your print surface you could also get the duet ir sensor.
    https://miscsolutions.wordpress.com/mini-height-sensor-board/

    i personally dont like the bltouch.
    i use this https://www.thingiverse.com/thing:3303618



  • The genuine one is typically significantly better than the clones.

    If you have a ferrous (steel) build plate directly/close to your print surface I've gotten very reliable data out of an inductive sensor.

    However - my aluminum beds (not very ferrous) with a thick PEI topper I've had alot of struggles with an inductive sensor and have since switched to a BL-Touch, which works quite well.


  • Moderator

    No single probe type is perfect. They all have strengths and weaknesses.

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

    BLTouch Pros:

    • works on any surface
    • temperature doesn't matter
    • fairly cheap
    • pretty accurate and repeatable
    • popular so lots of hotend mounts are already available
    • version 3 is fairly refined by now

    BLTouch Cons:

    • Can potentially be influenced by strong magnets
    • requires an offset from the nozzle tip
    • pin is fragile and won't take much abuse
    • 5 long wires to extend and connect correctly
    • relatively involved configuration
    • clones are often poor quality

    To be fair to the BLTouch, it is a good probe option. If you judge it by the number of support issues, you may think it's junk, but keep in mind that most of the time those are clones, and the volume is high because it's so popular. Also most of the issues come down to wiring or configuration errors.



  • Personally, I favour the Precision Piezo probes (genuine ones, not clones) and while I have used BLTouchs' (also genuine), I found them more difficult to configure & reliably use, whereas the Precision Piezo probes just work, more reliable, no probe to get stuck\damaged and no probe offset.



  • Precision Piezo works very good and consistent once you have a good setup (sensitivity, probe speed, and Hotend Temp.).
    One of the big benefits is, that you don't have an offset from the printing nose.

    I changed from BLTouch to Precision Piezo and I quite happy.

    Cheers


  • Moderator

    Precision Piezo Pros:

    • Uses nozzle tip, so no offset
    • Can be very repeatable and accurate
    • No moving parts
    • simple wiring
    • works on any bed surface

    Precision Piezo Cons:

    • Can be tricky to get tuned to reliable triggering
    • nozzle must be clean and preheated to soften stuck plastic
    • Fewer mounting options available and can be difficult to implement
    • Clones are often poor quality


  • Is BL Touch the best option?

    I am not sure if there is a 'best' but the BL Touch is a very solid option. I like it because it works with any bed material, easy to add the the head, and is mainstream so have good community support.

    The clones do work and are less expensive but if you can afford get the real one as it will save you doubts whether problems you encounter are clone related.



  • @Hornetrider said in Is BL Touch the best option?:

    Precision Piezo works very good

    Do they relay on the nozzle touching the heatbed? Is there a problem if the nozzle has filament oozing from it?


  • Moderator

    @zapta said in Is BL Touch the best option?:

    @Hornetrider said in Is BL Touch the best option?:

    Precision Piezo works very good

    Do they relay on the nozzle touching the heatbed? Is there a problem if the nozzle has filament oozing from it?

    Yes and yes.



  • Well, if filament is oozing from the nozzle, it ain't a big deal.
    I have set the hotend temp to 210 Deg C. With this setup it does not really matter.

    If you run a bed compensation (measurement) it is recommendable to have the filament retracted as far a possible form the hotend. I do this only for the measurement that I run once in a while...I have no need to run it on every print.



  • As part of my slicer config\running print setup, I mimic the Prusa MK2\Mk3 machines and perform a nine point bed levelling routine, when everything is heated to running temperature.

    This ensures that I have an accurate levelling measurement for any particular print.



  • @Hornetrider said in Is BL Touch the best option?:

    Well, if filament is oozing from the nozzle, it ain't a big deal.

    What about the travel distance from detection to stop? That is, is there sufficient distance to stop before the head get damaged?

    (trying to understand, not to criticize).



  • I have a Ender 3 with a Duet 2 Maestro fitted and a genuine BL touch, it consistently works every time with no problems, I haven't used any other type of sensor so can't compare but I just wouldn't swap it.


  • Moderator

    @zapta the piezoelectric is very sensitive and triggers at the slightest tap. The trigger height is consequently slightly negative (-0.1mm) or so. Similar to the smart effector.



  • @Phaedrux, my concern is that once the bed touches the nozzle and it get detected, the heavy bed will continue to move a small distance before stopping, as with inertia, and will apply force to the head. With IR, BLTouch, Switches and inductive, the detection is done before the bed reaches the nozzle.

    Is it an issue?



  • No, it's not an issue IF you are set up properly. On the other hand, in my setup I could not get consistent triggering over the entire bed. As a result, some areas would trigger perfectly and other spots would have stuff deflecting everywhere as the nozzle met the bed and carried on.
    In some areas that was a minor issue where it just reflected in reduced accuracy and there were other areas where things would drive into each other more than a few mm's 😞



  • my exp:

    • original bltouch (2 and 3) - repeatable, reliable, dependable,easy to setup. the only problem I have is offset and inability to reach whole bed
    • clone bltouch (one that looks like original), not repeatable (huge error), died after less than a month (tried 2)
    • clone bltouch (black), repeatable (not as original but acceptable, way better than cap/ind probes), running for 6m without problem
    • precisepiezo hotend original (v1, not new fancy pcb), superb, best ever, can't be mounted everywhere (I use: thing:2658639)
    • preciosepiezo hotend made by me -> 100% same as original v1
    • precisionpiezo hotend clones (tried few) pot very low quality, had to replace 6 of them, rest like original
    • precisionpiezo for bed original v1 - shit 😞 don't work for me
    • precisionpiezo for bed clones - shit 😞 dont work for me
    • precisionpiezo for bed original v2 (andromeda) - in process of testing on ender 5, so far I love it but too soon to say

    its only my experience on some ~10 printers



  • To aid the setting up of the Precision Piezo(s), I replaced the single turn potentiometer, with a multi turn type.

    This gives far greater control of sweet-spot settings, and ensure I get consistent repeatable reading across a 300x300 mm bed.


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