Migrating to Cura: nozzle prime at start of print

Discussion in 'Tool heads & ToolChanger' started by Jai Stanley, Oct 21, 2019.

  1. Jai Stanley

    Jai Stanley Well-Known Member

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    Gents,

    I have become a little frustrated with Simplify 3D to date; especially with regard to it's profiles. After 4 years I am still perplexed by the way it retains material profiles and print settings. Also I hate the way it handles the Z seam.

    This weekend I have been trying Cura. LOTS of granularity to the settings available and actually seems to be in active development. Simplify 3D is VERY stagant in that regard also.

    I am struggling with a few things.. Notably the prime of the nozzle at the start of the print.

    In S3D the start script encompases the first layer: deselect tool, home, run mesh bed levelling (I have multiple build plates with sifferent surfaces for different materials and might forget when I change beds), select whichever tool, run a prime line at the edge of the bed then start print.

    Cura breaks this into two: start of Gcode script, then tool select script.. I have inserted the deselect tool, home and mesh here. Then for each tool it has a tool startup script.

    I might be getting snow-blind but can't think where to put a prime script.. If I put it in the tool select script it will run it when changing tools during a print (am I correct?) therefore make a mess on every tool change (not just the first layer).

    Other than adding a model of the line, I'm not sure how to achieve the same as I have in S3d. Can anyone help?

    Kind regards,

    Jai
     
  2. Spoon Unit

    Spoon Unit Well-Known Member

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    I put my prime script in the start script for the print. It really depends what you mean by prime. If you're just referring to the last-minute-re-prime-before-printing, this can be handled by the Duet as part of toolchange code, where it will indeed prime (and/or purge) with every tool change. If you're talking about something to just confirm everything is working, then that's more like my prime scripts, which just prints a single solid line from each extruder to be used in the print.
     
  3. Jai Stanley

    Jai Stanley Well-Known Member

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    Well, I've done a bit of tinkering.

    I added the last minute prime along the bed at the very start of the print to the toolhead script and it works... But this is a: me being a throw-back to a now soon to be forgotten time, and b: not having printed any multi-tool prints with cura yet.

    I was having real issue with the purge and prime scripts not having the correct ammount of material in the nozzle so as to prevent a string or an under extruded section on the print. Think playing with the point where the extrusion distance is zeroed will fix it. Zeroing before a retraction lets the machine know how far back in the melt path the laterial is, so it de-retracts the correct amount. Alas, I've not tried multi nozzle prints so can't report back if I'm right yet or not..
     
  4. Andy Cohen

    Andy Cohen Well-Known Member

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    Yeah... watch out... when you start doing lots of tool changes everything you think you have dialed in goes right out the window....
    I cannot recall, can cura do an ooze shield? Also you will find that controlling the 4 tools requires a heckalot more of the process capability of s3d then you are seeing with just 1 tool.
    I do love Cura but once you get the complexities of s3dwith multitools (see my s3d pita thread) it will do more then cura can.
     
  5. Jai Stanley

    Jai Stanley Well-Known Member

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    So I'm currently switching back and forth between the two.

    S3D frustrates the tits off me with its handling of materials and settings. I have saved factory files for each material and or type of print I do; but the granularity of settings and the lack of any meaningful updates compared to Cura still sticks in my craw.

    I don't often do lots of tool swap prints at the moment. I use the multiple tool heads as just that: One has a 0.25mm nozzle, one a 0.4 nozzle x, one a 0.4 copper coated (currently off) and one has a 0.8 volcano.

    I'd very much like to design a tool head that has a filament cutter just before the hot end heatsink and utilise a prusa style filament swapper for multi-colour; but thats some distance off!!
     
  6. greenlee

    greenlee Member

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    If you just using the E3D machine in single tool type mode without a wiper then the initial prime would be in the startup Gcode section of machine settings.
    Cura by default picks up the first active tool at the start of the job then runs the startup g-code.

    But, that would not help much when you go to use multiple tools in a single job.
    If you have not implemented the wiper then you probably want to use a prime tower or ooze shield, i was using a prime tower personally before building and enabling the wiper.
    Note i usually disable unused tools in cura.
    Note2 Cura 4.3.1 was picking up the first tool and purging it when i used prime tower with any other tool even though the first tool wasn't used in the job. I haven't tested this in 4.4.0beta.
     

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