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3D print holes in walls


troubleshooting - Gaps/Holes in the 3D Print walls

I'm new to 3D printing, I bought an Ender 5 Pro just recently. Trying to print with 1.75 mm PLA, but the results are very bad, unfortunately. When I got after bed leveling I got a decent result from the demo dog and started to print small things, where the quality was acceptable. Then I tried to switch to bigger items, but the printing failed half-way due to not enough adhesion.

There were other quality problems too with this print, and you can already see that in the walls there are holes:

I did another round of bed leveling and Z alignment to make sure the adhesion is good and a test print came out quite fine in all corners and the center. The one layer rectangles and not perfect, in some places the lines separate, but they are mostly fine. But now I have a different problem: all the prints are very messy, less clear, they are not as strong as before and also there are big holes now in the walls. The same statue base (as I had to stop after getting messy earlier) looks like this now:

Another try failed after a few hours (like printing stopped and was printing nothing in the air), but also there is the holes/gaps problem even more visible:

Finally as a test I printed an object with the same G-code as previously used and the result is much different. The object on the left is the new one. It is weak, you can feel by pressing that the walls are not solid, they bend. The rectangle "eyes" are also not clear:

There is a difference though, I changed the extruder's nozzle between, the new one was also in the Ender package, it is also 0.4 mm as the original should have been, I changed to try with a new one.

Because of the last test with the same gcode, different result, I think the problem might be in hardware adjustment as well, not only software. Anyone has an idea what I'm doing wrong?

EDIT 1: after calibrating the extraction amount and reducing the print temperature from 200 C to 190 C, now I get the below result. The values used:

  • Bed temperature: 65 C initial, 60 C for the rest
  • Print temperature: 200 C initial, 190 later
  • Print speed: 80 mm/s
  • Wall speed: 40 mm/s
  • Retraction: 10 mm
  • Retraction speed: 80 mm
  • Wall thickness: 0.8mm
  • Layer height: 0. 2 mm
  • Initial layer: 0.2 mm
  • Line width: 0.4 mm

EDIT 2: Based on the comments, some changes were made and here are the results. XYZ cube,

  • print speed reduced to 60 mm
  • layer height 0.12 mm
  • Z Seam Alignment is Sharpest Corner
  • Infill density 30 %
  • Retraction distance 8 mm
  • Retraction speed 40 mm

It looks good, the layers are visible though, some ghosting right to X and Y. The sizes are not correct though: X = 20.07 mm, Y = 20.03 mm, Z = 19.84 mm

Are X/Y acceptable? What should I do with Z, increase steps/mm ?

Finally here is the 3D benchy too, although looks mostly fine, there are some bumps in the walls and small strings in open areas. This was printed earlier and with different settings though:

  • Layer Width 0.2 mm
  • Print speed 80 mm
  • Retraction 10 mm
  • Retraction speed 80 mm
  • Z Seam Alignment is set to Random

EDIT 3 I tried now to print the PolyPearl, that has thin curving lines. 2$ (default is 500)

  • Print jerk: 8 mm/s (default is 10)
  • Retraction distance: 8 mm
  • Retraction speed: 40 mm/s

    • The model sticks well to the glass plate even without glue or hair spray, maybe a little too well. I see some problems though, not sure how normal they are:

    • outside area of first layer is not nice
    • there is some oozing, thing lines on the surface and between the columns
    • the top end of the tower is somewhat messy and there is a horizontal line attached to it (sure, can be removed easily)
    • the bottom is very smooth, I can see the glass' texture (the Creality glass top is textured) and the texture of the very first failed print, when I didn't take into account the extra height of the glass after leveling, and the print head hit it hard and the nozzle got completely damaged. Beginner's fault.

    Here are the images: https://photos.app.goo.gl/ZfuMFFedL171eLeM7

    Are this problems normal/acceptable?

    ultimaker cura - How to fix wall separation in 3D prints (gaps in between wall perimeters)?

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    The print is very solid except for the 4 walls.

    From the top, I can slide a paper down to the bottom. This is ONLY between the walls, the rest of the print is solid. The filament is PLA 1.75 mm.

    But the bottom is solid, no gaps.

    I have checked the usual problems on Ultimaker troubleshooting photo gallery, but I can find anything similar.

    Any advice to fix this would be very welcome.

    Print settings:

    • print-quality
    • ultimaker-cura
    • 3d-design

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    To fix this, I had results with the following way:

    • Change your extrusion width from being equal to your nozzle size (0.4 mm) to slightly larger (I use 0.45 mm). That way you better combat the shrinking of the filament.
    • Having the Print thin walls setting activated to force the printer to print intermediary walls if there are areas where less than the prescribed wall thickness for a single wall fills in spaces that are as a result of the wider outer walls left. The result for a 1.2 mm wall, the central part is a 0.3 mm zigzag.
    • Lower the extrusion temperature a tad as hotter filament shrinks more on cooling! For PLA about 200 °C is my sweet spot.

    Additionally, there are extra steps that could be taken: * Finally, you could play around a little with the extrusion multiplier to try to get rid of the tiny bit of under extrusion you have. * Calibration could help too.

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    Now that print settings are shared we can see that this problem is not related to too fast printing (only 20 mm/s) or too low print temperature (210 °C should get PLA fluid enough). To explain this, a low temperature and too fast printing cause under-extruded lines.

    There are 2 other causes that might be worth investigating:

    1. Under-extrusion. From the top layers one can see that there may be insufficient material printed. Calibration of the extruder helps in this respect.
    2. Inaccurate positioning. This may for instance be caused by loose belts or a mechanical defect.

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    I've experienced this too, especially with flex modified PLA filament. For that, fixing underextrusion and increasing temperature made it go away. Sadly Cura has no option to overlap walls slightly (if printed in the right order, this could be done without affecting dimensional accuracy) except possibly the outer one, so you really have to get extrusion rate calibrated right or this will happen.

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    Look for the horizontal expansion setting in Cura. By default it should be zero. The description includes this:

    Positive values can help compensate for too big holes.

    The "holes" here includes these gaps. You can set it to something very small (ie: .01 or .03, probably no more than .05) and that will likely be enough to get it to fill in those gaps.

    Unfortunately, I only have a little direct personal experience with this setting, hence the probably/likely weasel words, and I can't give much real guidance on exactly how big or small you can go with this.

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    3

    (There is a solution) Gaps/holes in 3D printing walls

    I am new to 3D printing, I recently bought an Ender 5 Pro. I'm trying to print with 1.75mm PLA but the results are very poor unfortunately. When I got there after leveling the table, I got a decent result from the display dog ​​and started printing small things where the quality was acceptable. I then tried to switch to larger items, but the print failed halfway through due to insufficient adhesion.

    There were other quality issues with this print and you can already see that there are holes in the walls:

    I did another round of table alignment and Z alignment to make sure the adhesion was good and the test print came out pretty good in all corners and center. Single-layer rectangles are not perfect, the lines split in some places, but mostly they are small. But now I have a different problem: all the prints are very dirty, less clear, they are not as strong as before, and there are also large holes in the walls. The same base of the statue (how I had to stop after getting dirty before) looks like this now:

    Another attempt failed after a few hours (e.g. printing stopped and printed nothing in the air), but there are also problems with holes/gaps even more noticeable:

    Finally, as a test, I printed an object with the same G-code as before, and the result is very different. The object on the left is the new one. It is weak, you can feel by pressing that the walls are not solid, they bend. The "eye" rectangle is also not clear:

    There is a difference though, I changed the extruder nozzle between, the new one was also in the Ender package, it is also 0.4mm, as the original should have been, I changed to try with the new one.

    Due to the last test with the same gcode and a different result, I think the problem may be in the hardware setting as well, not just in the software. Does anyone know what I'm doing wrong?

    EDIT 1 : after calibrating the ejection amount and lowering the print temperature from 200 C to 190 C, now I get the following result. Used values:

    • Table temperature: 65 C initial, 60 C for others
    • Printing temperature: 200 C initial, 190 later
    • Print speed: 80 mm/s
    • Wall speed: 40 mm/s
    • Retraction: 10 mm
    • Retraction speed: 80 mm
    • Wall thickness: 0.8 mm
    • Layer height: 0.2 mm
    • Starting layer: 0.2 mm
    • Line width: 0. 4 mm

    EDIT 2 : Based on the comments, some changes have been made and here are the results. Cube XYZ,

    • print speed reduced to 60 mm
    • layer height 0.12 mm
    • Seam alignment Z is the sharpest corner
    • Fill density 30%
    • Retraction distance 8 mm
    • Retraction speed 40 mm

    It looks good, although the layers are visible, some ghosts right on X and Y. Dimensions not correct though: X=20.07mm, Y=20.03mm, Z=19.84 mm

    Are X/Y allowed? What to do with Z, increase steps/mm ?

    Finally, here's the 3D benchy too, although it looks mostly ok, there are some bumps in the walls and small strings in the exposed areas. This has been printed previously and with different settings though:

    • Layer Width 0.2mm
    • Print speed 80 mm
    • Retraction 10 mm
    • Retraction speed 80 mm
    • Z Seam alignment set randomly

    EDIT 3 I tried now to print a polypearl which has thin curved lines. The first attempt failed after 2 hours, a pen appeared on the nozzle, which ruined the print. It was a print from 190 p. I gave it another try and printed with 200 C and surprisingly it completed the job. See below photos, here are my settings for it (changes for Cura 4.6.0 default Super Quality):

    • Layer Height: 0.08mm
    • Initial layer height: 0.12 mm 92$ (default 500)
    • Print jerk: 8 mm/s (default 10)
    • Retraction distance: 8 mm
    • Retraction speed: 40 mm/s

    The model adheres well to the glass plate even without glue or hairspray, maybe a little too well. I see some problems, although I'm not sure how normal they are:

    • the outer area of ​​the first layer is not very pleasant
    • there are some oozing, strange lines on the surface and between the columns
    • The top end of the turret is somewhat dirty and has a horizontal line attached to it (of course, it can be easily removed).
    • the bottom is very smooth, I can see the texture of the glass (the top of the Creality glass is textured) and the texture of the very first failed print when I didn't take into account the extra height of the glass after leveling and the print head hit it hard and the nozzle was completely damaged. Rookie mistake.

    These images are here: https://photos.app.goo.gl/ZfuMFFedL171eLeM7

    Are these problems normal/acceptable?

    ▲ 4

    Let's see what errors I'm seeing (accumulated from what I've commented):

    The legs seem to be very weak. This can be either a clogged nozzle, printing too fast, or too low a temperature, or too low a pressure (for example, an incorrectly calibrated extruder). Try cleaning or a fresh nozzle, another parameter game can wait after you fix the next big problem.

    To fix under extrusion if it persists after fixing the chime, experiment with the following settings:

    • Check the mechanical system. Make sure the extruder
      • has no defects. I saw a lot of underextrusions when my extruder arm broke. The gear turned, but no longer pressed on the thread.
      • presses the filament with the idler bearing well against the hob gear.
      • is properly calibrated for physical parameters. Use the extrusion multiplier to account for different materials.
    • Temperature. If the extrusion is not going well, increase it by a factor of 5. The °C steps can help.

    The dented cube shows this best: massive ringing occurs. This is the effect that occurs when the printer changes direction rapidly - the printhead cannot speed up and slow down indefinitely as it has momentum, and as a result oscillates around the new path a bit, like a sine ring. This creates a "ghost" of previous toolpath changes on the flat face, which is why I asked for the cube to be printed.

    There are 2 software fixes to fix ghosting and ringing:

    • Reduce the print speed.
      • this comes at the cost of longer print times
    • Improve your maximum acceleration and jerk
      • Slightly lowering the maximum acceleration (from 500 mm/s2 to 1000 mm/s2) can significantly improve print quality with little to no effect on overall print time and keep print speeds high.
      • Jerk is a derivative of acceleration; figuring out the two values ​​that might be best for setting up a printer can be a lot of experimentation.

    There is also a hardware way to reduce it in many designs by shaving weight off moving parts or strengthening the design:

    • Get a lighter printhead
      • removal of unnecessary add-ons
      • replacement for lighter print head design
      • transition to Bowden design
      • in CoreXY: use lighter rails
    • Toughen the structure
      • Adjust the carriage mount so that it compresses better
      • replacement of bearings and bushings with bearings with tighter tolerances
      • ties can significantly strengthen the structure of the portal and cube

    This could come from any of several sources. In descending order of similarity:

    • the first layer is not a multiple of the actual layers (eg 0.12 instead of 0.2 mm), resulting in a partial layer at the top of the cut. in the example given, this would result in a fixed negative error of of about 0. 08 mm.
    • Incorrectly calibrated first layer. Depending on your alignment skills this can result in a fixed error of up to 0.1mm for a bad calibration up to 0.025mm for a really good calibration. This error can be either positive or negative.
    • Z-axis inconsistencies due to misaligned lead screw, sticky lead screw, or insufficient Z-step motor voltage. Both tend to create a systematic error - as when printing a given percent loss of height. Such inconsistencies can be eliminated by solving the problem mentioned: first check the orthogonality, then carefully lubricate the screw with light machine oil (not WD40!), finally, increase the motor voltage a little. Only if your results are severely out of order, you should check if your steps/mm are set correctly. But I don't see the need for it.

    , @ Trish

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