Jump to content

Discontinuity in Cura Fill Behavior vs. Fill Setting


calinb

Recommended Posts

Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

The photo sequence is:

1. 24% (single layer)

2. 25% (single layer)

3. 25% (two layers)

Note that Cura prints a full hatch pattern per layer at 24% but only "half" a hatch pattern per layer at 25%. More significantly, the overall hatch density increases disproportionately at 25%, compared to the 24% fill setting. I'm trying to obtain a hatch density somewhere between 24% and 25%. Is there a way to do it?

I printed it both ways and the Rep-Host depiction is correct and accurate.

For reference, the grid is the standard Rep-Host grid (10 mm).

Thanks!

gallery_908_249_93582.jpg

gallery_908_249_86301.jpg

gallery_908_249_22954.jpg

 

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Yes, this is a known behavior. At around 25% (it's related to the bead-to-gap spacing ratio, iirc) Cura changes from doing both directions on a layer to only doing one direction at a time. The spacing gets closer together then to maintain the volumetric infill percentage, given that in any given direction, every other layer is empty. i.e., the closer spacing is needed to ensure that 25% of the internal volume still contains plastic, taking into account that the vertical density is now half what it was.

     

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Not sure what you're trying to do Cal but I know that 25% is the cut off point in Cura where it changes from cross hatching on the same layer to cross hatching on 2 layers.

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Thanks, guys.

    Regardless of whether Cura does both directions per layer or only one direction, I'd like the final cross-hatch density to be roughly half-way in between the 24% and 25% settings. Just eyeballing the diagonals on the grid, Cura approximately doubles the hatch density from about 2-3/4 cross hatch lines / diagonal (14.14mm) to about 6 cross hatch lines / diagonal (or ~5.1 mm spacing to ~2.4 mm spacing. I'd like to print something with around 3 or 4 mm spacing.

    This is a manufacturing die that must withstand pressures somewhere in the range of 100 to 500 psi. I'm printing nylon for its chemical resistance, strength and, to some extent, the desirable properties of flexibility and compressibility. However, I must balance the compression of a sparse hatch density against the significant propensity of printed nylon to warp. Cura doesn't seem to support the "sweet spot" that I need.

    Like support, there's always the option to just design the cross hatch into the model (and I've found this to be necessary for support in Cura nylon prints), but it's nice when a slicer can produce these features automatically, as necessary.

     

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Yes, I agree that it would be nice to have more control over the spacing: having something in the range that you're looking for would be useful; the wider gaps can be a bit too wide for easy bridging, while the close ones are unnecessarily close.

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    For this very specific need I recommend Cura 13.04 or a different slicer all together (like kisslicer).

    Older versions of cura here:

    http://software.ultimaker.com/old/

    Cura switched to a whole new slicing engine at version 13.05 so version 13.04 or older will do a good job with your infill. You can choose hex infill, or other patterns. Or the default "random lines" pattern.

     

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Sure--I have Kisslicer Pro and I use all the slicers, including netfabb. They all have their strengths and weaknesses. Cura is now the fastest slicer, but it is currently lacking features (speed and limited feature set both being related to the newness of the core engine, I'm sure). Kisslicer is unreasonably fault-intolerant of model imperfections. My models are often very complex and it's impossible to process very complex models in Kisslicer without some weirdness occurring somewhere in the gcode. Netfabb is very buggy and poorly supported by its commercial owner (which I've mostly learned to workaround) and it can produce unacceptable inaccuracies in dimensions (it's "Pythagorean-challenged" when printing on a diagonal, for example) but it offers the most control off all the slicers by far. Slic3er provides an average of all the other slicer's traits.

    That's my very brief summary of slicers, as I see them. This model has about 100,000 triangles, which isn't too bad, and the old Skeinforge Cura will probably be my next choice, even though it will take a lot longer to slice than with Steamengine Cura.

     

    For this very specific need I recommend Cura 13.04 or a different slicer all together (like kisslicer).

    Older versions of cura here:

    http://software.ultimaker.com/old/

    Cura switched to a whole new slicing engine at version 13.05 so version 13.04 or older will do a good job with your infill. You can choose hex infill, or other patterns. Or the default "random lines" pattern.

     

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    For sure, but at least PA6 and 618 nylon bridge large gaps wonderfully!

     

    Yes, I agree that it would be nice to have more control over the spacing: having something in the range that you're looking for would be useful; the wider gaps can be a bit too wide for easy bridging, while the close ones are unnecessarily close.

     

  • Link to post
    Share on other sites

    Posted · Discontinuity in Cura Fill Behavior vs. Fill Setting

    Right now the code works like this, the distance between infill lines is calculated for the line infill. This distance is between the center-line of the lines. If this distance is more then 4x the extrusion width then it does the grid infill at double that distance.

    This logic was made to prevent the grid infill from happening at high densities, because at high densities the corners of the grid would get too much material and cause problems. If 4x distance is the best option, I'm not sure. I just picked something that made sense in my head.

    There is always the battle between fine grain control and ease of use. I'm still pondering to make the main logic of the slicer scripted, so you can tweak things like this at will...

     

  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • S-Line Firmware 8.3.0 was released Nov. 20th on the "Latest" firmware branch.
        (Sorry, was out of office when this released)

        This update is for...
        All UltiMaker S series  
        New features
         
        Temperature status. During print preparation, the temperatures of the print cores and build plate will be shown on the display. This gives a better indication of the progress and remaining wait time. Save log files in paused state. It is now possible to save the printer's log files to USB if the currently active print job is paused. Previously, the Dump logs to USB option was only enabled if the printer was in idle state. Confirm print removal via Digital Factory. If the printer is connected to the Digital Factory, it is now possible to confirm the removal of a previous print job via the Digital Factory interface. This is useful in situations where the build plate is clear, but the operator forgot to select Confirm removal on the printer’s display. Visit this page for more information about this feature.
          • Like
        • 0 replies
      • Ultimaker Cura 5.6 stable released
        Cura now supports Method series printers!
         
        A year after the merger of Ultimaker and MakerBotQQ, we have unlocked the ability for users of our Method series printers to slice files using UltiMaker Cura. As of this release, users can find profiles for our Method and Method XL printers, as well as material profiles for ABS-R, ABS-CF, and RapidRinse. Meaning it’s now possible to use either Cura or the existing cloud-slicing software CloudPrint when printing with these printers or materials
        • 48 replies
    ×
    ×
    • Create New...