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Machine zero in the wrong direction

Discussion in 'General Electronics' started by Jack Soliman, May 25, 2021.

  1. Jack Soliman

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    I have a lead 1015 and I mounted the home switches at the front left of the machine.

    I can move the axis in the right directions. So X goes right in the positive direction, Y goes back in the positive direction, and Z goes down in the negative direction.

    Then, I home the X and Y in the negative directions which is the correct direction towards my limit switches. The machine zeros just fine.

    Now I believe the machine stores the homing position at this point 5mm from where the limit switches were triggered.

    When I move the X, for example, then I click "Goto x-5.000 (Machine Coord) (G53 G0 X0)"
    This should send the X back to machine zero, which is in the negative direction. But.. it goes right (in the positive), away from the limit switch that it just zerod at??

    I am talking machine zero not work zero here. Anyone can help me understand what's wrong?

    I attached few pics.
     

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  2. Jack Soliman

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    This is a private link to a video I just made on my YouTube channel.

     
  3. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Checkout gnea/grbl

    Home is not where the switches are: its at the back, right and top

    After homing in your video at about 00:45 when you say "at this point right here" is incorrect. It "established" that home is set, but machine zero is still at the Axis Maximas as it should be, regardless of where the switches are
     
    Alex Chambers likes this.
  4. Jack Soliman

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    Thank you. This makes sense, but I'm still confused about something!

    When the machine is done with a job it goes back correctly to the limit switches position, 5mm away to be exact.

    So where is this position saved?

    And I actually read this article and where it said:
    "simply uncomment the HOMING_FORCE_SET_ORIGIN option in the config.h file."

    But I can't find this file.

    Is there a way I can save the position of the limit switches (front left) as the machine zero coordinates?
     
  5. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Paste the snippet from an end of gcode file please - depends largely on which CAM, which Post, etc was used. Suspect you have Fusion, the wrong post, and probably finds a G28 in there near the end (;


    That would cause a lot of issues for you, stick to that standard coordinate systems, CAMs expect it to be in a certain place


    As a beginner, don't do that. But for later reference, see gnea/grbl
     
    #5 Peter Van Der Walt, May 25, 2021
    Last edited: May 25, 2021
  6. Jack Soliman

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    I sent you a picture of the ending of the g code program.

    I just don't understand why the machine is going to machine zero at a location that is not defined? I didn't zero there and I don't even have limit switches in the back!
     

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  7. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    G28 = user settable parking position. Its not going to machine zero. Its going to G28 which is coincidentally at last homed spot because its not been set. The fact that that that's in the gcode tells me I was right:

    So, to avoid all confusion, please use the OpenBuilds Fusion Post: doesn't use weird G28 stuff. See docs:software:fusion360 [OpenBuilds Documentation]

    Also fixes some bugs in the default post, brings back Rapids that they took away from the free licence, and much more
     
    Alex Chambers and sharmstr like this.

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