Tools absolute coordinates work badly



  • I am using DUET 3D for my Pick and Place maschine. I have two nozzles set as extruders - Tool 0 and Tool 1 - everything works fine with relative coordinates (3D printers). However, I need to work in absolute coordinates and it works badly after switching from tool 0 to tool 1 and vice versa.

    Problem: 1) At the begining - tool 0 and tool 1 is at position 0 degrees
    2) I set tool 0 to 90 degrees (it moves correctly from 0->90 degrees)
    3) Switches to tool 1 and want to move from 0 to 20 degrees
    4) PROBLEM: tool 1 moves -70 degrees instead of +20 degrees because it inherites the position from tool 0.


  • Moderator

    @kiwi I'd guess the answer is to either

    1. Set tool position back to 0 degrees before changing tools (do this tfree[tool#].g; see https://duet3d.dozuki.com/Wiki/ConfiguringRepRapFirmwareCartesianPrinter#Section_Tool_change_files for clarity on tool changing files)
      or
    2. If you don't want to return tools to 0 degrees before tool change, you can use G60 to save current position (and G1 R0/1/2 to reload it)
      or
    3. Use a combination of G10 workplace coordinate offsets and/or G54 to G59.3 coordinate system, though I'm not sure how or if this would work.

    If the rotational axis is defined as axis U, I think using G60 would work, with, for example T0 saving to G60 S0 and T1 saving to G60 S1 on each tool change. Then, when changing from T0 to T1, save with G60 S0, change to T1, then run G1 R1 U0, which will set U to the Tool1's previous position, but not change X, Y or Z. I think!

    Ian



  • Thanks @DROFTARTS for your help and ideas.

    To point 1. - yes this is possible and works well but not possible to use for my Pick and Place maschine. I cannot change the position of the other tool during process.

    to point 2. - yes it works well for axis X, Y ..and so on... but not for Extruders axis defined as tools. It is desired only for tool position, not for the tool itsefl (if I understand it well ...but I tried many hours and still no reaction to G60) So I can move the whole maschine to the saved position, but tool remains the same.

    To point 3. is the same problem as the point 2. ...it is possible to works with axis X etc. ...but tools are problems.

    To problem of positioning: I want to add that:

    1. At the begining - tool 0 and tool 1 is at position 0 degrees
    2. I set tool 0 to 90 degrees (it moves correctly from 0->90 degrees)
    3. Switches to tool 1 and want to move from 0 to 20 degrees
    4. PROBLEM: tool 1 moves -70 degrees instead of +20 degrees because it inherites the position from tool 0.
      ADDED:
    5. It inherites the position from tool 0 ALWAYS and badly work with + and -

    Example: T0 is at the position 10000 (now swithing to T1)
    T1 G1 E1000 set T1 to -9000 or 11000 - so the absolute coordinates now works as absolute difference between tools

    Only when the other tool is at the position 0 - then the other tool is working correctly.



  • And a note:

    In relative mode the extruders (defined as tools) work perfectly and correctly (this is standart printer mode). However, I need the absolute one and I think - there was no issue because of no use of this mode.

    @dc42 Hi David, I saw a comment that you are ready to help with integrating the DUET 3D to the other maschine like Pick and Place. My vision is to sell this maschine like a Prusa printer. However, I need to solve how to use two nozzles - now only one is working. Thanks for any help.


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