anomalies at 0.35mm layer, fade at 0.25mm: what's happening?

Discussion in 'Calibration, Help, and Troubleshooting' started by R Design, Mar 25, 2016.

  1. R Design

    R Design Well-Known Member

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    IMG_0149.jpg Last night installed the Volcano + 0.6mm nozzle.

    First impressions: this could be great!

    Two problems:

    1) so far have not been able to get the fan above 25% without thermal runaway;

    It's starting to seem like the volcano block needs some kind of protection from the parts fan. Anyone else using it?

    2) I'm getting lines at the corner edges of the 2cm test cube, particularly at higher layer heights. Have printed in light gray in lit in the most unflattering way so that you can see. The one on the left (0.35mm layers) is printed with:

    outer perimeter 12.5mm/s (25% full speed)
    hypothetical full speed: 50mm/2
    infill: 75% of 50mm/s

    The lines occur where the nozzle zooms in to start the infill from the other side of the cube.

    The one on the right has the same settings but 0.25mm layers.

    What's going on?

    I reckon that when the print head is accelerated by the belt it leans in to the direction where it's going, and the outer edge of the nozzle comes up a fraction, leaving a deposit behind. At a lower layer height it can't come up so much.

    The print speeds seem really low and with the Volcano I was planning on doing some bigger layer heights. What can I try?

    ps yes both cubes are warped upwards towards the top because the fan is still only at 25%. However dimensionally speaking they are great! ;)
     
    #1 R Design, Mar 25, 2016
    Last edited: Mar 26, 2016
  2. Mike Kelly

    Mike Kelly Volunteer

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    Looks like ribbing. Did you get the Z axis improvements if you have an earlier acrylic?
     
  3. R Design

    R Design Well-Known Member

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    Yes I have the new Z axis system.

    The little deposits seem to occur in a way that is related to the infill. Each time that the nozzle comes to the end of an external perimeter and then zooms off somewhere else, that's where it happens.

    Initially I thought I could correct it by using the "coast" feature in S3d, but to no avail.

    Really have no idea what's going on but for a variety of reasons I've started to imagine that it's the print head tilting slightly as it moves off???
     
  4. mike01hu

    mike01hu Well-Known Member

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    It seems strange that the problem repeats every fourth layer but you might want to try adjusting the outer perimeter speed, making it slower to reduce any inertia effects. You didn't say what the material is or the temperatures being used. I have had that curl effect in the past due to the nozzle temperature being too high but the strange repetitive nature I don't understand. By the way, it is still there on the 0.25mm layers but less so.
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    I think the issue is probably related to having less shells (presuming you're using only one), and still a relatively high (15%) infill overlap. I reckon if you went for two shells, that could be sufficient to fix it.
     
  6. R Design

    R Design Well-Known Member

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    It's ColorFabb XT.

    There are 3 shells.

    It repeats every fourth layer at a given corner because the nozzle circuits around the corners.

    Factory file attached, anyone curious will see that there are little flashes of red travel movement at each corner as you scroll through the layers.
     

    Attached Files:

  7. Mike Kelly

    Mike Kelly Volunteer

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    If you print slower does it still happen?
     
  8. R Design

    R Design Well-Known Member

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    Yes. I've gone slower and slower. Even tried the XY movement speed is set (painful) at 12.5mm/s.

    Totally perplexed.
     
  9. Mike Kelly

    Mike Kelly Volunteer

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    Calibrated your E Steps?
     
  10. Spoon Unit

    Spoon Unit Well-Known Member

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    I reckon that might just be simple overextrusion now looking at it again. I should perhaps retry estep calibration, just to give it another go, but I'm manually tweaking flow per material, or more truthfully, on the fly.
     
  11. R Design

    R Design Well-Known Member

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    Went on to trying different types of infill.

    My conclusion is that here was trying an awkward infill / dimension of part combination: other varieties and percentages worked fine.

    I think the artefacts came from:

    a) the travel direction imposed by the start point of the infill caused the nozzle to leave the perimeter seam on a long slow diagonal across the outer perimeter;

    b) the volcano oozes;

    The two combined to create an unacceptable level of artefaction.
     

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