Upgraded extruder, nozzle offset clarification.



  • I recently upgraded my extruder to an E3D Hemera. The extruder and nozzle are positioned differently from the previous setup. When I home the X axis now, the nozzle is now off the build plate by ~3mm (or -3mm X direction). And when I home the Y axis, the nozzle is about ~10mm into the build area (or +10mm Y direction).

    I saw when defining the tool you can set an offset with the G10 command. I also watched a video of someone doing their extruder upgrade and using the M206 command to set the axis offset from the nozzle.

    So my question is G10 or M206? And do I pass the offsets like they are (-3, 10) or do I reverse them? Maybe that's different depending on which of these two commands I use.


  • Moderator

    @rschlachter If you only have one nozzle, I'd just adjust the M208 command. Having your only nozzle with an offset will just get confusing. See: https://duet3d.dozuki.com/Wiki/Centering_the_bed_or_setting_the_bed_origin

    Ian



  • Agreed. Axis definitions should put the only nozzle, or Tool zero nozzle, where you want 0,0 to be. There should be no tool offset. If only one tool, end of story.

    If multi tools, the XY offset for T0 should always be X0Y0. Literally G10 P0 X0Y0. Each succeeding tool then has an offset from that baseline. G10 P1 X-.892 Y1.234 or whatever.

    It is physically possible to accomplish tool-to-tool alignment several other ways, but they are confusing as heck. T0 establishes X0Y0 is the way to go.




  • Moderator

    @rschlachter I'm no expert on workplace coordinates, tool offsets and coordinate systems. It's my understanding that M206 was the early way of doing workplace coordinates, but limited to only one set. Using G10 and various other Gcodes (G54 to G59.3) are for multiple tool environments, really. If you only have one tool, stick with M208.

    Ian



  • Correct. M206 predates workspace coordinate systems (g54, g55, ...). It is not used (by any sane persons) anymore. It hasn't been removed so as not to break really old G-Code.

    For one thing, it is EXACTLY equivalent to G10 L20 P2 (except the coordinate offsets are interpreted the "other way", formally as if monotonically negated). So just use that...

    Workspace Coordinate Systems (WCS) are very rarely used on 3D printers. They are quite common on CNC, but even there most people don't really understand how they work. Even some fairly experienced CNC operators.

    For now, summarize:

    • M206 is legacy. Avoid.
    • WCSs are an intermediate to advanced topic on CNC, and very very rare on 3D Print. Avoid until you have a really compelling reason to dive into them.

    Also, re-summary to the very original Q: X0 Y0 for Tool 0 via the axis definitions (and nothing else); each other tool (if any) is offset to that.


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