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I've done calibration test with "Concentric circle test" (https://www.thingiverse.com/thing:11895) and at specific points there are little bumped points on the print. Also Thingiverse page of the test mentions about these.

How can I solve this problem?

My printer is Creality Ender 3 Pro, I use Esun PLA+ with 210 celcius extruder and 60 celcius bed temperature.

Here is the printed object, both are same print, just took photo on different base.

enter image description here

enter image description here

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  • $\begingroup$ Interesting question. Now I want to try that test piece and possibly Marlin 1.1.9. $\endgroup$ – R.. GitHub STOP HELPING ICE Jun 26 '19 at 14:26
  • $\begingroup$ Sure looks like overextrusion $\endgroup$ – Carl Witthoft Jun 27 '19 at 14:32
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It looks like you have the bed adjusted too high, smashing the layers together and causing "elephant foot" not just on the bed but also on features - the rings - near the bottom of the print. You might also have over-extrusion, due to an increased material flow setting, actual filament diameter greater than the setting in the slicer, or miscalibration of the E axis steps per mm.

From the second image, it looks like you might have another problem: I think I'm seeing infill lines through the gaps between the rings, rather than seeing top-surface skin in the bottom of the grooves. If so, this is a bug in Cura's default settings where "skin" in narrow regions is completely lost due to "preshrink". The skin preshrink values should be set no larger than the nozzle/line width, possibly zero, and skin expansion can be lowered by the same amount or more as long as it remains greater than or equal to the preshrink value. If my assessment of what I'm seeing is correct, fixing it should result in the grooves being supported properly rather than resting on infill lines.

What you're seeing is definitely not normal or expected from this printer. Here's what you should be seeing:

enter image description here enter image description here

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  • $\begingroup$ Bed could be a little high, I'll check that. My nozzle is 0.4mm and I print with 0.15mm , could this be the reason for increased flow? Should I change nozzle for more precise prints like that? For the second problem, I'll try that, in fact this is the first nice, smooth first layer of my all prints (I'm newbie), I guess it's corrected after leveling X-axis but if you say it can be better, I'll surely try your recommendations.. Thank you :) $\endgroup$ – she hates me Jun 26 '19 at 14:33
  • $\begingroup$ Oh, I missed that you're the same poster with the gantry problem. I suspect you may still have an issue with it and inability to level the bed; that can cause layers getting smashed together when Z moves are unreliable. $\endgroup$ – R.. GitHub STOP HELPING ICE Jun 26 '19 at 20:45
  • $\begingroup$ My bed is a little warped on the center, it seems that's common problem for Ender 3 beds, I'm thinking about buying a glass bed. But for this print, I don't think it's related to bed leveling (except high bed) because diameter of the circle is just 4 cm. $\endgroup$ – she hates me Jun 26 '19 at 21:56
  • $\begingroup$ Well if the center is significantly higher than the corners and you leveled based on the corners, that could do it. Make sure you can drag a sheet of paper under the nozzle at Z=0 near the center of the bed with only slight drag. $\endgroup$ – R.. GitHub STOP HELPING ICE Jun 26 '19 at 22:08
  • $\begingroup$ Today I tried again with lowered bed and it printed absolutely much better. Thank you :) $\endgroup$ – she hates me Jun 27 '19 at 15:35
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We had some prints like that recently. Turns out it was caused by the bed not being "level" or "trammed". Basically the nozzle was too far off the bed when printing started for the first layer. Check yours - a piece of paper should slide between the nozzle and the bed surface, with a little bit of resistance. If it slides freely, the bed needs to be raised some. Check it at the corners and in the middle of the bed.

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I've not sliced the part in question, but the over extrusion mentioned in the third point (at change of direction/layers) is referring to ooze.

This is a result of the hydraulic pressure in the melt zone, and results in over extrusion at any point when the print head is moving slowly (and a corresponding under-extrusion once motion resumes). It can be compensated for by retraction and coasting settings.

This effect will probably not be visible in the print you have here, there are other effects which are causing more significant defects.

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