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Outer Wall Bulges/Artifacts and a Possible Diagnosis  

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scott.v3
(@scott-v3)
Active Member
Outer Wall Bulges/Artifacts and a Possible Diagnosis

Hi all,

I just purchased an MK3 kit and have been putting it through its paces. After successful prints with the provided grey/silver, I swapped for white and a PLA/PHA teal. After fine tuning Z-heights, I've got some solid heights established, but now my layers are not exactly skipping or displacing, but it's like I've got a wobble in my X-Axis. The photo here

shows some green and white prints that illustrate my issue. I've found some others on here that have shown these same problems, and even found a Youtube video ( ) talking about the issue. I've identified a few variables to test out the reasons as to why this is occurring.

Currently using:
-Prusa MK3 Kit w/ Firmware ver. 3.3.1
-Slic3r Prusa Edition V1.40.1+win64

Hardware Observations:

  • Prior to the exterior wall print quality issue, I removed, cleaned, and returned the nozzle. After replacing, the wobble geometry appeared in the exterior walls.
  • Inspection of machine's turret after the bad prints produced a wobble in the hotend box that the nozzle threads into. This could have been caused by the hot end removal, or could have existed to some degree prior. I recall some looseness to the box when gripping to unthread the hot end, but didn't think it was an issue.
  • Variables:

  • I have performed multiple z-calibrations between replacement of nozzle in hotend and printing with wall issues.
  • I changed my software settings to print as:
  • Seam Position: "Aligned"

  • External Perimeters First: "True"
  • (COOLED TO ROOM TEMP FIRST) I removed the fans and front cover of the turret, exposing the heater inside the turret and, while gripping the box for the hot end, spun the seated body of the hotend in place clockwise from top down, tightening the box into the cylindrical honeycomb shaped body.
  • Diagnosis & Conclusion:

    I believe my issue was caused by a loose connection in the E3D Hotend between the aluminum "honeycomb-shaped" body and the box with the wire exists at the bottom. Tightening this connection resulted in no wobble in the nozzle, and a successful print. This tightening step should be included in the instruction manual (chapter 5, step 19) after the Hotend is seated into the turret body. Here's the latest print in progress, post-adjustment:

    If others would like, I can do a test with the software variables turned off to account for them, but the physical difference in the machine's stability at the nozzle is definitively better to the point that I can confidently say that I believe it to be the cause.

    Thanks!

    3D printing for furniture hardware designs and aesthetic scale models.

    Posted : 31/07/2018 7:19 pm
    talz13
    (@talz13)
    Eminent Member
    Re: Outer Wall Bulges/Artifacts and a Possible Diagnosis

    The embedded pics in the post aren't loading for me, do you have links to them?

    Prusa i3 MK3 kit
    MK3/S Upgrade Kit
    FW 3.7.0
    Slic3r PE 1.41.3

    Posted : 31/07/2018 7:59 pm
    scott.v3
    (@scott-v3)
    Active Member
    Topic starter answered:
    Re: Outer Wall Bulges/Artifacts and a Possible Diagnosis

    I edited it for a different host. Should be working now.

    3D printing for furniture hardware designs and aesthetic scale models.

    Posted : 31/07/2018 8:24 pm
    Kazibole
    (@kazibole)
    Eminent Member
    Re: Outer Wall Bulges/Artifacts and a Possible Diagnosis

    Neat! Do you have a picture of the items you tightened? Some of my prints are exhibiting the same pattern.

    Posted : 31/07/2018 8:26 pm
    scott.v3
    (@scott-v3)
    Active Member
    Topic starter answered:
    Re: Outer Wall Bulges/Artifacts and a Possible Diagnosis

    Yes, look in your assembly instruction manual, under "5. E-axis Assembly", "Step 18 - Inserting the E3D Hotend" and "Step 19 - Mounting the Extruder-Cover" here: https://manual.prusa3d.com/Guide/5.+E-axis+assembly/510?lang=en#s8196

    The hotend assembly has that ribbed alum body, and a "box" at the bottom with the brass nozzle screwed into it and wires coming out the side. With my printer assembled, I removed the screws holding on the two fans, and then the 2 screws holding on the front black 3d printed component that's called "Extruder Cover" from step 19. That left the front of the turret open. From there, I held the "box" shape at the bottom of the hotend in place, and used my fingers to rotate the metal part above it. It's shipped to you assembled, but it is only threaded together, and the heatsink section is perfectly round, so it can rotate, and there won't be anything to stop it from doing so aside from friction once it's all assembled, so that's why I say it's worth adding to the assembly instructions so it's not skipped over.

    3D printing for furniture hardware designs and aesthetic scale models.

    Posted : 31/07/2018 8:47 pm
    Nikolai
    (@nikolai)
    Noble Member
    Re: Outer Wall Bulges/Artifacts and a Possible Diagnosis


    Yes, look in your assembly instruction manual, under "5. E-axis Assembly", "Step 18 - Inserting the E3D Hotend" and "Step 19 - Mounting the Extruder-Cover" here: https://manual.prusa3d.com/Guide/5.+E-axis+assembly/510?lang=en#s8196

    The hotend assembly has that ribbed alum body, and a "box" at the bottom with the brass nozzle screwed into it and wires coming out the side. With my printer assembled, I removed the screws holding on the two fans, and then the 2 screws holding on the front black 3d printed component that's called "Extruder Cover" from step 19. That left the front of the turret open. From there, I held the "box" shape at the bottom of the hotend in place, and used my fingers to rotate the metal part above it. It's shipped to you assembled, but it is only threaded together, and the heatsink section is perfectly round, so it can rotate, and there won't be anything to stop it from doing so aside from friction once it's all assembled, so that's why I say it's worth adding to the assembly instructions so it's not skipped over.

    Actually it would make sense to add a new step with the whole E3D hotend check. Not only loosen parts but also a PTFE tube length and correct aligned cables.

    Often linked posts:
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    Real Multi Material
    My prints on Instagram

    Posted : 01/08/2018 1:52 am
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