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Z offset for different slicers

Discussion in 'Software' started by Kingbob, Aug 19, 2014.

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  1. Ziggy

    Ziggy Moderator
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    Why not ? After the G29 is completed the x, y and z positions are all known. eg a X home after that is no different than going to X0.

    Anyway the reset is built into Marlin for better or worse. But like many other "features" in Marlin there is no documentation. And now that R3d have created their own private fork of Marlin it's even more difficult to keep track of changes.
     
    #21 Ziggy, Sep 15, 2014
  2. Mike Kelly

    Mike Kelly Volunteer

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    Going to X0 is a controlled motion. It's a calculated position. When it home it truncates all position information and looks for the switch trigger.
     
    #22 Mike Kelly, Sep 15, 2014
  3. Ziggy

    Ziggy Moderator
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    Well not quite all. Because if you home X and Y Marlin still remembers the Z position.
     
    #23 Ziggy, Sep 15, 2014
  4. Mike Kelly

    Mike Kelly Volunteer

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    Ok well you got me on that, though when I said "All" I meant for that axis. Since it homes Z after X and Y I would assume it would truncate Z as well since it doesn't know the Z sensing position is still accurate.

    In a way though it makes sense because if you assume a flat bed then the home position wouldn't really change much on the Z.
     
    #24 Mike Kelly, Sep 16, 2014
  5. Island Bill

    Island Bill Active Member

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    I can confirm this behavior.
     
    #25 Island Bill, Sep 18, 2014
  6. sal

    sal New Member

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    G1 Z1.4 ;Raise Nozzle 1.4 (This is the offset on my printer)
    G92 Z0 ;Force new Z0

    Thanks, this worked for me using Repetier and cura
     
    #26 sal, Sep 29, 2014
    2 people like this.
  7. sal

    sal New Member

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    FYI, I have much better prints with auto level disabled
     
    #27 sal, Oct 8, 2014
  8. ssshake

    ssshake Member

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    where did you guys get your offset from? Today's the first I'm hearing about this and I've had my printer for months. I can't get it to smash down a good layer on just glass, it's clearly too high. If I add tape it just makes the cut.

    Considering I dont know my z offset what can I do?
     
    #28 ssshake, Oct 13, 2014
  9. sal

    sal New Member

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    Do you know the thickness of the tape? if not start with .1mm offset with the above gcode.
    This number will change with the life of the printer. I had to change mine again this weekend.
    Changed from 1.4mm to 1.3mm offset and auto level disabled.
     
    #29 sal, Oct 13, 2014
  10. ssshake

    ssshake Member

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    The tape measures .2mm on my cheap calipers.

    I arbitrarily set it to +0.4 (M565 Z0.4) and that actually got it smashing down a good looking first layer on bare glass and works on tape too. I'm a little confused by all of this, is setting the offset something everyone should do or is this a hack/work-around to my problem? If we're supposed to set it I wish it was more clearly explained when I got my printer.
     
    #30 ssshake, Oct 13, 2014
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If I understand correctly, the auto-level printers came with that number (the offset) attached (somewhere). You should have had a sheet of paper (or something) with that number specified.

    You can however experiment with it to find the optimal number for your printer (sounds like that is what you are doing). Pick a number and print a perimeter. If it is correctly put down you are good, if not, adjust and redo. Sort of like us beta guys do with the manual Z axis screw :)
     
    #31 mark tomlinson, Oct 13, 2014
  12. sal

    sal New Member

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    Mine smashes the glass without offset. Try 10mm first. that would put you well above the glass. then work your way down.
     
    #32 sal, Oct 13, 2014
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