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Black Box32 auto square

Discussion in 'General Talk' started by Hykr3n, Mar 21, 2024.

  1. Hykr3n

    Hykr3n New
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    Hi hive mind.
    id like to try auto square feature on my sphinx

    I already have 2 limits switch on my y axe,

    Machine is pretty squared but i like fiddling and im ocd. Be

    Do i have to recompile grbl or there a way to make it work on control?
    Thanks
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    You can enable it in the grblHAL Web Builder. Wire the Y2 switch in Parallel with Z and ensure Z homes on its own ($44=4, $45=3) (Sharing with Z, and since Z is not checked during XY homing, can be used to check Y2)

    Do note its often easier to build the machine squarely, rather than using the motors to force an unsquare machine into square on every homing run (likely better for any components subjected to these forces long term as well) - plus positioning those switches to be square is quite an effort sometimes - we've not really found autosquaring to be a fun experience :)

    See Tramming: A generic guideline
     
  3. Hykr3n

    Hykr3n New
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    Machine is pretty square.
    but i found my self loving work on machine rather than using it ;)

    what you mean by forcing it?
    I should only mesure discrepancies and re aling gantry?

    i instaled a 4 z nema on my 3d printer and using klipper i have 3d mapping running at 0.006 of accuracy

    it should work the same way?
     
  4. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Well, if there's anything for autosquare to correct, the machine wasn't square right?

    Applying that correction, means something that was bolted together in a way where its not square, now has to be pulled by the motor that hasn't reached the switch yet, against its natural state, either by deflecting extrusions or mount - to get it "straight" until it triggers the switch. And then locked in that position by the motors. Pulling on the frame using the linear motion components.

    Even a minor offset means using linear components to constrain the machine into square. Extra wear on leadnuts. Wheels taking axial forces. Extrusions or brackets bending ever so slightly. And it has to do this while the machine is running, and often even in storage - not really backdriving a leadscrew machine that easily, it probably stays "pulled square" when its off too, but those loads keep forces on the linear components.

    That corrects a "flat plane" mounted on floating corners to ensure all four corners lie in the same plane. Not like a CNC frame thats rigid...
     
    David the swarfer likes this.
  5. Hykr3n

    Hykr3n New
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    oh your right!
    It is my ocd, i just wanted to put a number on it.

    to see the error margin and work from there.
    i dont see that feature as a band aid but more as a starting point to ensure perfection.

    is it what we want from machinist?
     
  6. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Well, from here, i see the margin of error in placing that second switch and then relying on the switch to be far inferior than to jog the machine into hard stops at the end of travel, on a base thats been checked for square with simple diagonal measurement checks. Machinists prefer accuracy yes, but well thought out :) and against fixed references (not bouncing switches with soft lever arms)

    Follow Tramming: A generic guideline and you'll get it way better than autosquare can

    Need a NUMBER to work from? Order a Dial Indicator :)


    Moving a lever limit switch in a V-Slot to exact same distance is one thing, but the levers have ever so slightly different trigger points too. Using something like inductive endstops - same - they are repeatable in themselves, but within a batch they all differ from each other so you can't just slide the switch a certain distance away from a fixed reference (same as other side) - the trigger point is a bit of a guess
     

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