Dude about precision piezo



  • Hi,

    I have ordered a Precision Piezo. .. And have a doub...
    How does it work? If I have not misunderstood, piezo precision is supposed to detect the bed when the nozzle is very close to the this. ... But ... How does Precision Piezo know ... That the nozzle is rubbing the bed? I have looked at the design of the adapter ... And I do not see Precision Piezo in contact with the extruder.



  • The nozzle bangs into the bed and the piezo produces a signal. I think the idea is good and bad. The nozzle has to be hot or at least free of stray material. In some ways it's an accident waiting to happen, but it has real advantages. The design of the carriage and it's durability, as well as the type of bed surface are factors. My fairly thick PEI over a MIC6 aluminum plate is very rugged so a piezo would probably work pretty well. The guy who designed my coreXY hates the idea of course. He says build it so stable you calibrate once and leave it. I would like the option to use a bit of mesh compensation though personally. I still have every intention of trying the piezo on mine. The latest iteration of that sensor no longer uses a piezo disc with a hole crudely drilled in the middle. They switched to a breadboard with flexy bits and smaller piezo discs. Looks like a massive improvement to me. I would prefer they stopped using 3D printed parts though and switched to something better.


  • administrators

    @peirof the sligt Z movement of the hotend in the mount when the nozzle touches the bed distorts the piezo disk, which is converted into a signal the duet understands ans a Z probe trigger. @DjDemonD can explain in more detail.



  • I use my Piezo to accurately locate my Z axis instead of an endstop.



  • Happy user here, 3 machines p.piezo powered, I do not use the printed mount but carriage mount and underbed mount and they never let me down...



  • @whosrdaddy said in Dude about precision piezo:

    Happy user here, 3 machines p.piezo powered, I do not use the printed mount but carriage mount and underbed mount and they never let me down...

    Could you please elaborate on carriage and under bed mounting, as I am interested in this option



  • Depends on the printer you have.

    On my i3 clone, I use this: https://www.thingiverse.com/thing:2705784

    On my CoreXY, I use underbed sensors with "noise canceling" piezos: https://www.youtube.com/watch?v=cgcDk_8NACc
    Gantry is powered by Z axis. The piezos are stuffed in TPU feet under the bed 's corners.

    Like I said, it all depends on the type of printer you have...



  • Hi yes, so its all on our website www.precisionpiezo.co.uk and on our reprap thread https://reprap.org/forum/read.php?1,767998 it a fully open source project so its not a secret.

    If you connect a piezo disc to an arduino and ask it to monitor the voltage on an analogue pin, you will see that they are incredibly sensitive, any slight vibration or certainly any deformation of the disc will generate a large voltage. Hit one with a hammer and you'll see 50v! (don't do this with your 5v arduino analogue pin please). This is how electronic lighters work, by striking a piezo hard and generating an arc.

    In the hotend sensor systems, the piezo disc is deformed when the nozzle contacts the bed. It only needs to be around 0.1m (which is repeatable so you can set this as a z offset) to give a signal, and can be very gentle when correctly tuned.

    There is no electrical contact between the Precision Piezo sensor and the hotend, this would be very undesirable as a short or wiring failure would create damage to Piezo PCB or 3d printer controller board.



  • I am currently using a Bltouch after not having much luck with the IR probe, but cant see how I would attach the piezo to my P3 Steel, under the bed? as I use metal x axis end's and carriage.



  • @boldnuts I use a carriage mount solution for my P3Steel see my thingiverse link I posted earlier...


 

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