Cura 2.4



  • @burtoogle:

    Hi, I am using the Cura bleeding edge (beyond 2.4) with my Duet powered Kossel XL.

    In Cura I have added a custom FDM printer - gcode flavour is RepRap.

    I then edited some of the machine settings to set dimensions, start/stop gcode, etc.

    The start gcode is:

    G28 ; home all axes
    G1 X0 Y0 Z25 F8000 ; descend
    M82 ; extruder absolute mode

    The end gcode is:

    M83 ; extruder relative mode
    M104 S0 ; turn off extruder
    M140 S0 ; turn off bed
    M106 S0 ; turn off fan
    G28 ; home
    M84 ; disable motors

    All of the Duet macros that fiddle with the extruder (load/unload, etc.) start with M83 to set relative mode.

    That's about it, if you have any specific questions, I am happy to respond.

    Ok, just to clarify, I shouldn't run M83 in the start code? I'm trying to get cura going now, but all I get is puddles of filament.

    Thanks for explaining, I am as my handle implies



  • No, the start code (what gets inserted at the top of each job) should have M82 to set absolute extruder mode which is what Cura uses.



  • Yup, that fixed it. slic3r worked fine for me, but cura went wonky. I'll have to research the difference between the exact and relative so I can better understand it, so I can better understand g code.

    Thanks!



  • @3dprinting:

    Yup, that fixed it. slic3r worked fine for me, but cura went wonky. I'll have to research the difference between the exact and relative so I can better understand it, so I can better understand g code.

    Thanks!

    Absolute sends the axis or extruder to a point relative to zero. Relative sends it to a point relative to where it is at the time the command was sent. So, if part way through a print, one had extruded say 100mm of filament then sent an absolute command to extrude to E103, it would extrude another 3mm to bring the absolute extrusion up to 103mm from zero. If it was relative, it would extrude 103mm of filament -i.e 103mm on top of the 100mm that had been extruded. You can tell if the gcode file has absolute extrusion commands because the values just keep increasing throughout the file (i.e they keep getting further away from the starting point of zero).



  • @deckingman:

    @3dprinting:

    Yup, that fixed it. slic3r worked fine for me, but cura went wonky. I'll have to research the difference between the exact and relative so I can better understand it, so I can better understand g code.

    Thanks!

    Absolute sends the axis or extruder to a point relative to zero. Relative sends it to a point relative to where it is at the time the command was sent. So, if part way through a print, one had extruded say 100mm of filament then sent an absolute command to extrude to E103, it would extrude another 3mm to bring the absolute extrusion up to 103mm from zero. If it was relative, it would extrude 103mm of filament -i.e 103mm on top of the 100mm that had been extruded. You can tell if the gcode file has absolute extrusion commands because the values just keep increasing throughout the file (i.e they keep getting further away from the starting point of zero).

    Ok, that makes a lot of sense. thank you.



  • Since these are two ways of doing the same thing what's are the pros/cons of using one over the other.



  • Hi DJ,

    I don't think there are any pros or cons of one vs the other (DC42 might step here with his usual well informed opinion though). It's all relative though - either relative to zero or relative to the current position. With Slic3r, we use a combination of both - absolute for X, Y and Z but relative for E.


  • administrators

    For axis movement both absolute and relative movement have their place.

    Absolute is require when you want the printer to go to a specific position when the current position could vary, an example of this is a purge/wipe macro where there is a specific location that the action needs to be carried out. Absolute is also alot easier to work with and read for.most other axis tasks.

    Relative movement is required when you want to move a specific distance, no matter what your start position. An example of this could be in end gcode, when you lift the hotend by a couple of mm before moving it away from the object.

    For extrusion there is less of a point in absolute movement, relative makes more sense in all situations. There is a small advantage in being able to look at the end of the file and see the total length of filament used but that is not really a good reason as most slicers add it up for you anyway. I am not sure why Cura has stuck with absolute extrusion, Ultimaker may have a reason or it may just be tradition.



  • Great discussion, but my oroginal question was how to connect Cura 2.4 to DuetWifi over netwrok, has anyone done this and if so how did they set up Cura?


  • administrators

    The network connectivity from Cura is specific to Ultimaker printers so you need to save the file and then upload it using DWC.



  • @T3P3Tony:

    The network connectivity from Cura is specific to Ultimaker printers so you need to save the file and then upload it using DWC.

    Actually, there is a Cura plugin that connects to Octoprint, so there is a way. I just haven't had time to hack into the code and figure it out for the Duet yet. If someone else wants to give it a shot, the Octoprint plugin is on gcode.


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