G2 driving A axis extruder

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  • November 3, 2014 at 7:28 pm #6965
    whitecloud
    Member

    I’m working with a scaled up Shapeoko which has a pump in place of the spindle. The pump is wired to M4 which is attributed to the A axis. I’m trying to drip liquid in a circle. Sending this simple gcode which starts at center, traces the path of a 400 mm circle, and returns back to center:

    G90

    F3000

    G0 X0 Y200

    G2 X200 Y0 I0 J-200 A100
    G2 X0 Y-200 I-200 J0 A200
    G2 X-200 Y0 I0 J200 A300
    G2 X0 Y200 I200 J0 A400

    G0 X0 Y0

    M0

    If I run the same code, replacing all instances of G2 with G1 I get a diamond and the A axis turns as expected. Why not with G2?

    November 4, 2014 at 6:35 am #6966
    cmcgrath5035
    Moderator

    Nothing immediately obvious.

    It might help others commenting if you make you full config file available for review. Suggest you use this method:

    If you feel like hacking, maybe try this:
    Edit your Gcode file so that the sequence of lines with G0/G1 commands that do work (all 6 lines) are followed by 6 lines with G0/G2 commands.
    You could also try G3 commands rather than G2, in case the issue is G2 unique.
    Maybe some sort of initialization of Axis issue?

    November 4, 2014 at 9:15 am #6967
    whitecloud
    Member

    Thanks – to further clarify: G2 is successfully tracing the intended circle but the pump (A) is not running as expected. I’ll try your suggestions out tonight. I’m also going to update my firmware (still running 0.96). Here’s a link to my settings on dropbox:

    https://www.dropbox.com/sh/0qlkbw80ikkxzzv/AADLUKhE0X0z8FUEshyixIlCa?dl=0

    November 4, 2014 at 6:40 pm #6968
    cmcgrath5035
    Moderator

    I can say with confidence that “if” there is an issue in tinyG FW, it will be corrected in a version later that 438.02 (current edge), so yes, you might as well go there first.

    Not much experience or knowledge of rotational parameters here, so A settings are hard to comment on without a lot of research. $atm = -1deg looks a bit strange, but of course why would that affect G2 and not G1 moves.

    More and more folks headed down this path, let us know how you make out.

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