Whenever I print, I tend to have a small dent that appears on several of my prints, that are not in the original design. These are not following the layer orientation.

As far as I notice, nothing blocks the extruder of my prusa-i3. I print with PLA, so not a material where I would expect weird behaviour.

Dent problem image

What could cause that problem?

  • $\begingroup$ what is the model? $\endgroup$ – Trish Apr 6 '19 at 17:43
  • $\begingroup$ @Trish: the model is one of the russian doll maze, available here: thingiverse.com/thing:2410748 $\endgroup$ – Emile D. Apr 6 '19 at 18:03
  • $\begingroup$ In case the question leads to the size of the wall, I don't think it is the issue, since it is always at least 3 nozzle large. $\endgroup$ – Emile D. Apr 6 '19 at 18:11
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    $\begingroup$ Looks like some kind of backlash issue with your printer. One way to know for sure is to print a part that has this issue, and then rotate the part in data and reprint. If the 'dent' stays in the same place relative to the bed/printer, then it's definitely a mechanical issue and not a data issue. $\endgroup$ – BobT Apr 6 '19 at 18:12
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    $\begingroup$ Also, looking at the rest of the print, aren't the side supposed to be smooth? In the thingiverse model, it appears to be so. I'd think you may need to tighten things up a little bit. Also, not sure how the nibs which run the maze are supposed to be supported during print or if there's enough overhang (or angle of the nib while printing) to allow it to print correctly at the top. If you have support turned on, could this be causing the issue where the nib is at? $\endgroup$ – Pᴀᴜʟsᴛᴇʀ2 Apr 6 '19 at 18:54

This looks very much like it is the seam between the outer perimeters that is placed one over the other. This can be solved by choosing a different Z-seam alignment. In Ultimatker Cura, the setting is called Z-seam alignment and should be set to random for cylindrical items.

  • $\begingroup$ Yes this is the seam (start/end of the outer wall perimeter), basically this printer is not calibrated correctly as this effect should be much less observable. Could be the filament is not available in time when the perimeter starts. $\endgroup$ – 0scar Apr 6 '19 at 22:55
  • $\begingroup$ Thank you for this information. I had no idea what this parameter was for. But it is likely there are also some calibration problem, as it was a printer I received in kit. What do you have in mind to fix the calibration problem, aside that probably I should tighten a bit more the belts? $\endgroup$ – Emile D. Apr 6 '19 at 23:47
  • $\begingroup$ Is this the same as setting to "spiralize" , at least for cylinders? $\endgroup$ – Carl Witthoft Apr 8 '19 at 15:24
  • $\begingroup$ I agree with Oscar that the general inconsistency in the wall of the upper object (in the photo) suggests problems with extrusion and/or excess backlash. $\endgroup$ – Carl Witthoft Apr 8 '19 at 15:25
  • $\begingroup$ @CarlWitthoft no, spiralize is the vase mode. $\endgroup$ – Trish Apr 8 '19 at 16:21

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