<p>Your top layer looks like you need to add additional top layers and there are signs of a slight bit of over-extrusion in that top layer (red). On the other hand, it looks like the top layer is not sliced nicely resulting in gaps and holes (yellow), which might be a fault of the test print.</p>
<p><a href="https://i.sstatic.net/pJooa.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/pJooa.jpg" alt="Z, defects marked" /></a></p>
<p>The X on the file you used is not centered, resulting in the off look in the print.</p>
<p>I suggest you try a different calibration print before starting to tinker with the hardware, for example <a href="https://www.thingiverse.com/thing:3090144" rel="nofollow noreferrer">this</a>.</p>
<p>I suggest to use concentric only for the top layers and instead rely on a simple Zig-Zag pattern for the intermediate layers, as this usually generates a better connection to straight walls.</p>
<h1>EDIT1:</h1>
<p>After considering the miss-dimension in X only, you might want to look to <a href="https://3dprinting.stackexchange.com/questions/3344/calibrating-steps-order">calibrate your X steps</a>.</p>
<p>The stretching of the belt might be an issue, but you might get away <em>easy</em> if you just check belt tension and manage to get it right again.</p>
<p>As I have an ender-3 myself, I know you might need to <a href="https://3dprinting.stackexchange.com/questions/6399/recalibrating-home-position">flash</a> <a href="https://3dprinting.stackexchange.com/questions/6657/export-firmware-as-a-hex?noredirect=1&amp;lq=1">fresh</a> firmware to get the ability to change the steps/mm.</p>
<h1>EDIT2:</h1>
<p>The 19x20x20mm cube sounds like the new belt did fix a lot of the dimensioning problem, but the steps/mm might be slightly off - or we have to trace down SOME mechanical error in the movement path. As a 140mm long test print also had a 1mm offset, a steps/mm error should be out.</p>
<p>After examining the machine with jb <a href="https://chat.stackexchange.com/rooms/83007/ender-3-calibration-cube-fail">in chat</a>, the bearing on the X-belt seemed to stick a tiny bit on one side.</p>
<p><a href="https://i.sstatic.net/qTjdg.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/qTjdg.jpg" alt="Ender3 X-tightener/bearing" /></a></p>
<p>Turning the large bolt of the assembly in an attempt to disassemble it without a wrench to hold the self-securing nut on the far side seemed enough to lessen the pressure on the core of the bearing, allowing it to spin freely. In addition, the belt was a little loose.</p>

CC BY-SA 4.0
2018-09-08T16:48:28.487Z
I 100% agree. Do you have any idea why my main issue was occurring i.e. the X wasn't centered/how squares came out rectangular and circles as ovals. I feel like it must be a belt problem
jb7852
CC BY-SA 4.0
2018-09-08T16:55:44.790Z
The x side is 18 mm though as if its squashed
jb7852
CC BY-SA 4.0
2018-09-09T12:28:51.683Z
@jb7852 The X of the  calibration cube from [Thingiverse that you printed](http://thingiverse.com/thing:1278865), is not in the center in the STL! I see the X off centered in my test cubes also. Note that this does not explain the 18 mm in size!
0scar
CC BY-SA 4.0
2018-09-08T16:34:31.227Z
2018-09-11T17:44:47.217Z
2020-06-18T08:29:41.667Z
Trish
<p>First, check that the calibration part you have is actually a cube. Maybe you downloaded a trick 'calibration cube' model. Cura will show he overall dimensions of any model which it is slicing.</p>

<p>Ignore any print quality issues first off. A hollow calibration cube is mainly used to check the X/Y/Z motion and so long as you print at a sensible (slow) speed), the other parameters shouldn't have much effect (so long as the first layer is OK, and you get within 30% of the right extrusion).</p>

<p>If the calibration cube is within +/- 0.5mm on each side, it's probably good. Under/over extrusion, caliper technique, etc, can explain this sort of variation, and you might want to use a bigger test part like <a href="https://www.thingiverse.com/thing:2566871" rel="nofollow noreferrer">this star on my thingiverse account</a> once you think you're close.</p>

<p>The 'steps per mm' setting is determined within the firmware, it is part of how your printer consumes G-code. For a delta printer, for example, there is some fancy maths to combine X/Y/Z into the motor movements. This means that you can't change steps/mm in Cura, you need to either change the firmware defaults and 'reset to factory settings', or modify the parameters in EEPROM by sending G-code.</p>

<p>Seeing too small a calibration part (for a Cartesian printer) can easily be explained by problems in the printer's motion system:</p>

<ul>
<li>Stepper missing steps due to jerk or acceleration too high</li>
<li>Stepper missing steps due to binding/friction in the bearings (Send <code>M84</code> to idle the stepper motor, and move X by hand)</li>
<li>Teeth missing on the drive belt (may show up on a diagonal 'bar' print)</li>
<li>Loose drive pinion (maybe backlash on the flat on the spindle means the problem is greater on small parts) - see below</li>
<li>Flex in the drive mechanism (e.g. belt mount to traveller is loose)</li>
</ul>

<p>An annoying feature of a lot of these problems is that for any particular repetitive sequence of steps, you might see a very consistent result. Even thought to problem is something being badly adjusted, it gives the impression that the problem is calibration.</p>

<p>The drive wheel is held in place with a grub screw, see this diagram from the Anet-A8 assembly diagram.</p>

<p><a href="https://i.sstatic.net/1C3fcb.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/1C3fcb.png" alt="Anet X-drive"></a></p>

CC BY-SA 4.0
2018-09-09T11:36:26.623Z
the inadequate first test cube model was what I suspected, but both having X=18/18.5 instead of 20 as in the model is a good sign something is off.
Trish
CC BY-SA 4.0
2018-09-11T12:33:03.960Z
@Trish So after purchasing a new X belt, the calibration cube was much closer at 19 x 20 x 20. But still not at a good enough tolerance. Additionally, when printing a cylinder, two relatively flat edges were printed with it either side (perpendicular to the x-axis), thoughts?
jb7852
CC BY-SA 4.0
2018-09-11T12:34:53.433Z
Similar to this https://www.reddit.com/r/3Dprinting/comments/2zw4zn/flat_sides_on_my_circle_prints_i_have_calibrated/
jb7852
CC BY-SA 4.0
2018-09-11T12:57:54.983Z
It feels relatively smooth, no bumps anything
jb7852
CC BY-SA 4.0
2018-09-11T13:06:24.640Z
Would tightening the belt in some way help e.g. on the motor or the point pictured here. https://imgur.com/gallery/6nvme2n
jb7852
CC BY-SA 4.0
2018-09-11T13:15:16.027Z
@jb7852 I created a chat for this question. https://chat.stackexchange.com/rooms/83007/ender-3-calibration-cube-fail
Sean Houlihane
CC BY-SA 4.0
2018-09-09T11:06:46.797Z
2018-09-11T14:22:50.530Z
2018-09-11T14:22:50.530Z
Sean Houlihane
<p>After noticing that my ender 3 couldn't print a 'perfect' circle I decided to use a <a href="https://www.thingiverse.com/thing:1278865" rel="nofollow noreferrer">calibration cube</a> to see if that could be the issue. These were my results:</p>
<p><a href="https://i.sstatic.net/OHJOF.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/OHJOF.jpg" alt="X Y Z" /></a></p>
<p>I did have some successful prints before noticing these problems but it would be great if anyone could help/find a solution.</p>
<p>I think it may be because of the belts tension as I had accidentally over stretched it by putting it over the wheels instead of under: is it worth getting a new belt then?</p>
<p>I use 20% infill, with triangle pattern in cura, using the standard 0.4mm nozzle.</p>
<h1>Edit</h1>
<p>After doing a <a href="https://www.thingiverse.com/thing:3090144" rel="nofollow noreferrer">different testprint</a> and measuring, it revealed that both had an accurate 20mm Y and Z, but only an 18.5mm X. Might I have destroyed my belt when I mounted it overstrained?</p>
<h1>Edit2:</h1>
<p>After purchasing a new X belt, the calibration cube was much closer at 19 x 20 x 20. But still not at a good enough tolerance for my liking. Additionally, when printing a cylinder, two relatively flat edges were printed with it either side (perpendicular to the x-axis).</p>

CC BY-SA 4.0
2018-09-08T16:33:23.633Z
what are your slicer's settings for "number of top layers"?
Trish
CC BY-SA 4.0
2018-09-08T16:46:25.550Z
@Trish I used Cura, would Slicer be better? For cura my top/bottom thickness is 0.6 mm; (the layer was 0.1 mm); the top thickness was 0.6 mm and top layers was 6
jb7852
CC BY-SA 4.0
2018-09-08T16:48:19.833Z
cura is perfectly fine. Any infill? what's the nozzle diameter?
Trish
CC BY-SA 4.0
2018-09-08T16:50:13.070Z
@Trish 20% triangle infill. I don't know about the nozzle diameter: default for ender 3 1.75mm
jb7852
CC BY-SA 4.0
2018-09-09T08:03:04.627Z
Mind updating photos of the new print? the 18.5 for 20 seems consistent as you said in chat.
Trish
CC BY-SA 4.0
2018-09-09T14:59:50.960Z
@jb7852 - I think the 1.75mm is the filament diameter ... it should be stamped directly on your nozzle what size it is. I'd suggest it's probably 0.4mm.
Pᴀᴜʟsᴛᴇʀ2
CC BY-SA 4.0
2018-09-09T22:19:00.280Z
This looks like missing steps or binding in x direction. Does the carriage run smooth with depowered steppers (M84)?
0scar
CC BY-SA 4.0
2020-05-15T01:16:29.237Z
My prints look almost erily identical on the cube test and i am getting bad circles. what was the best solution? did you ever fix it?
Chris Yates
<print-quality><creality-ender-3>
Ender 3 Calibration Cube Fail + Can't Print Circles
jb7852
# Ender 3 Calibration Cube Fail + Can't Print Circles

(Asked by: username_0 on 2018-09-08)

After noticing that my ender 3 couldn't print a 'perfect' circle I decided to use a [calibration cube](https://www.thingiverse.com/thing:1278865) to see if that could be the issue. These were my results:

[![X Y Z](https://i.sstatic.net/OHJOF.jpg)](https://i.sstatic.net/OHJOF.jpg)

I did have some successful prints before noticing these problems but it would be great if anyone could help/find a solution.

I think it may be because of the belts tension as I had accidentally over stretched it by putting it over the wheels instead of under: is it worth getting a new belt then?

I use 20% infill, with triangle pattern in cura, using the standard 0.4mm nozzle.

# Edit

After doing a [different testprint](https://www.thingiverse.com/thing:3090144) and measuring, it revealed that both had an accurate 20mm Y and Z, but only an 18.5mm X. Might I have destroyed my belt when I mounted it overstrained?

# Edit2:

After purchasing a new X belt, the calibration cube was much closer at 19 x 20 x 20. But still not at a good enough tolerance for my liking. Additionally, when printing a cylinder, two relatively flat edges were printed with it either side (perpendicular to the x-axis).

**Tags:** print-quality, creality-ender-3
> **Comments:**
> **username_1**: what are your slicer's settings for "number of top layers"?  
> **username_0**: @Trish I used Cura, would Slicer be better? For cura my top/bottom thickness is 0.6 mm; (the layer was 0.1 mm); the top thickness was 0.6 mm and top layers was 6  
> **username_1**: cura is perfectly fine. Any infill? what's the nozzle diameter?  
> **username_0**: @Trish 20% triangle infill. I don't know about the nozzle diameter: default for ender 3 1.75mm  
> **username_1**: Mind updating photos of the new print? the 18.5 for 20 seems consistent as you said in chat.  
> **username_2**: @jb7852 - I think the 1.75mm is the filament diameter ... it should be stamped directly on your nozzle what size it is. I'd suggest it's probably 0.4mm.  
> **username_3**: This looks like missing steps or binding in x direction. Does the carriage run smooth with depowered steppers (M84)?  
> **username_4**: My prints look almost erily identical on the cube test and i am getting bad circles. what was the best solution? did you ever fix it?  

---

## 2 answers

### Answer by username_1 on 2018-09-08. Score: 3 | Accepted answer

Your top layer looks like you need to add additional top layers and there are signs of a slight bit of over-extrusion in that top layer (red). On the other hand, it looks like the top layer is not sliced nicely resulting in gaps and holes (yellow), which might be a fault of the test print.

[![Z, defects marked](https://i.sstatic.net/pJooa.jpg)](https://i.sstatic.net/pJooa.jpg)

The X on the file you used is not centered, resulting in the off look in the print.

I suggest you try a different calibration print before starting to tinker with the hardware, for example [this](https://www.thingiverse.com/thing:3090144).

I suggest to use concentric only for the top layers and instead rely on a simple Zig-Zag pattern for the intermediate layers, as this usually generates a better connection to straight walls.

# EDIT1:

After considering the miss-dimension in X only, you might want to look to [calibrate your X steps](https://3dprinting.stackexchange.com/questions/3344/calibrating-steps-order).

The stretching of the belt might be an issue, but you might get away *easy* if you just check belt tension and manage to get it right again.

As I have an ender-3 myself, I know you might need to [flash](https://3dprinting.stackexchange.com/questions/6399/recalibrating-home-position) [fresh](https://3dprinting.stackexchange.com/questions/6657/export-firmware-as-a-hex?noredirect=1&lq=1) firmware to get the ability to change the steps/mm.

# EDIT2:

The 19x20x20mm cube sounds like the new belt did fix a lot of the dimensioning problem, but the steps/mm might be slightly off - or we have to trace down SOME mechanical error in the movement path. As a 140mm long test print also had a 1mm offset, a steps/mm error should be out.

After examining the machine with jb [in chat](https://chat.stackexchange.com/rooms/83007/ender-3-calibration-cube-fail), the bearing on the X-belt seemed to stick a tiny bit on one side.

[![Ender3 X-tightener/bearing](https://i.sstatic.net/qTjdg.jpg)](https://i.sstatic.net/qTjdg.jpg)

Turning the large bolt of the assembly in an attempt to disassemble it without a wrench to hold the self-securing nut on the far side seemed enough to lessen the pressure on the core of the bearing, allowing it to spin freely. In addition, the belt was a little loose.

> **Comments:**
> **username_0**: I 100% agree. Do you have any idea why my main issue was occurring i.e. the X wasn't centered/how squares came out rectangular and circles as ovals. I feel like it must be a belt problem  
> **username_0**: The x side is 18 mm though as if its squashed  
> **username_3**: @jb7852 The X of the  calibration cube from [Thingiverse that you printed](http://thingiverse.com/thing:1278865), is not in the center in the STL! I see the X off centered in my test cubes also. Note that this does not explain the 18 mm in size!  

---

### Answer by username_5 on 2018-09-09. Score: 4

First, check that the calibration part you have is actually a cube. Maybe you downloaded a trick 'calibration cube' model. Cura will show he overall dimensions of any model which it is slicing.

Ignore any print quality issues first off. A hollow calibration cube is mainly used to check the X/Y/Z motion and so long as you print at a sensible (slow) speed), the other parameters shouldn't have much effect (so long as the first layer is OK, and you get within 30% of the right extrusion).

If the calibration cube is within +/- 0.5mm on each side, it's probably good. Under/over extrusion, caliper technique, etc, can explain this sort of variation, and you might want to use a bigger test part like [this star on my thingiverse account](https://www.thingiverse.com/thing:2566871) once you think you're close.

The 'steps per mm' setting is determined within the firmware, it is part of how your printer consumes G-code. For a delta printer, for example, there is some fancy maths to combine X/Y/Z into the motor movements. This means that you can't change steps/mm in Cura, you need to either change the firmware defaults and 'reset to factory settings', or modify the parameters in EEPROM by sending G-code.

Seeing too small a calibration part (for a Cartesian printer) can easily be explained by problems in the printer's motion system:

* Stepper missing steps due to jerk or acceleration too high
* Stepper missing steps due to binding/friction in the bearings (Send `M84` to idle the stepper motor, and move X by hand)
* Teeth missing on the drive belt (may show up on a diagonal 'bar' print)
* Loose drive pinion (maybe backlash on the flat on the spindle means the problem is greater on small parts) - see below
* Flex in the drive mechanism (e.g. belt mount to traveller is loose)

An annoying feature of a lot of these problems is that for any particular repetitive sequence of steps, you might see a very consistent result. Even thought to problem is something being badly adjusted, it gives the impression that the problem is calibration.

The drive wheel is held in place with a grub screw, see this diagram from the Anet-A8 assembly diagram.

[![Anet X-drive](https://i.sstatic.net/1C3fcb.png)](https://i.sstatic.net/1C3fcb.png)

> **Comments:**
> **username_1**: the inadequate first test cube model was what I suspected, but both having X=18/18.5 instead of 20 as in the model is a good sign something is off.  
> **username_0**: @Trish So after purchasing a new X belt, the calibration cube was much closer at 19 x 20 x 20. But still not at a good enough tolerance. Additionally, when printing a cylinder, two relatively flat edges were printed with it either side (perpendicular to the x-axis), thoughts?  
> **username_0**: Similar to this https://www.reddit.com/r/3Dprinting/comments/2zw4zn/flat_sides_on_my_circle_prints_i_have_calibrated/  
> **username_0**: It feels relatively smooth, no bumps anything  
> **username_0**: Would tightening the belt in some way help e.g. on the motor or the point pictured here. https://imgur.com/gallery/6nvme2n  
> **username_5**: @jb7852 I created a chat for this question. https://chat.stackexchange.com/rooms/83007/ender-3-calibration-cube-fail  

---

