<p>This differs from the traditional banding as observed from Z wobble induced banding as e.g. explained in <a href="/a/5824">this answer</a>.</p>

<p>Your banding patterns clearly seem to form diagonal bands, this is most probably a combination of the lead and the full rotation of the stepper. The most logical explanation is that the layer shifts as a whole in X-Y direction (when seen against the print height, this movement is concentric seen from the top). This means that the next layer is positioned over the previous layer in a concentric pattern. This hints to some sort of defect in your X/Y-plane assembly and should be investigated further. </p>

<p>This is difficult to visualize, but this sketch shows the issue for some layers:</p>

<p><a href="https://i.sstatic.net/5CzDk.png" rel="nofollow noreferrer" title="Diagonal Z banding by concentric consecutive offsets"><img src="https://i.sstatic.net/5CzDk.png" alt="Diagonal Z banding by concentric consecutive offsets" title="Diagonal Z banding by concentric consecutive offsets"></a></p>

<p>This could be related to the belts of the X and Y-axis, play on the drive pulleys, non-straight lead screw, guide rods with play, play in general, <a href="https://hackaday.io/project/14823-monoprice-select-mini-maximum-3d-printer-mods/log/51880-dont-go-wobbly-on-me-now" rel="nofollow noreferrer">Z-stepper alignment to the threaded rod</a>, etc. Considering the amount of <a href="https://www.mpselectmini.com/thingiverse/z-axis-stabilizers" rel="nofollow noreferrer">Z-wobble fixes</a> shared by the unofficial MP Select Wiki, the best place to look for is the Z-stepper to lead screw coupling.</p>

CC BY-SA 4.0
2019-07-04T03:55:42.460Z
It sounds like the lead screw might be bent (thus applying forces in the X and Y directions dependent on its rotational orientation) and like the Y axis belt may have more play/elasticity in it (or X if I read the description backwards).
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2019-07-04T18:28:26.907Z
Thank you @0scar! I think your diagnosis is spot on. I checked slop and belts on Y axis before but didn't consider that bed heating cable might snag underneath the rails thus impeding proper Y positioning. I wouldn't expect this effect to have periodic rather than random effect though. but the issue is almost gone after repositioning of the cable.
Andrew Butenko
CC BY-SA 4.0
2019-07-03T08:07:40.540Z
2019-07-03T12:10:27.300Z
2019-07-03T12:10:27.300Z
0scar
<p>The printer is <a href="https://www.monoprice.com/product?p_id=21711" rel="nofollow noreferrer">"Monoprice MP Select Mini 3D Printer V2"</a>.</p>

<p>This is how my printed fan part looks like:</p>

<p><a href="https://i.sstatic.net/BG8lC.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/BG8lC.jpg" alt="Printed fan part"></a></p>

<p>These printers are notorious for their Z lead screw assembly (M4 bolt &amp; nut) so I installed flex coupler and aligned the M4 bolt and motor shaft so that the wobble is minimal. It is still there, but I don't think this amount of wobble would produce something like what I experience. Please check out the <a href="https://photos.app.goo.gl/XTdaZMjGvCgwsZ9W7" rel="nofollow noreferrer">timelapse video</a> at the end.</p>

<p>I also tightened up Z guide rails (no rattle, very little slop)</p>

<p>Moreover the banding appears to be less pronounced and have alot greater period for vase prints <a href="https://i.sstatic.net/dJBLe.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/dJBLe.jpg" alt="Vase print; extruded ellipse printed along Y axis"></a></p>

<p>(this is extruded ellipse printed along Y axis).
I tried:</p>

<ol>
<li><p>slowing down print by 50&nbsp;% - no effect on banding.   </p></li>
<li><p>monitored hotend temperature with external probe on the heater block (-+5&nbsp;&deg;C)</p></li>
</ol>

<p>The banding appears to be almost exclusively in Y axis direction; for example, the same ellipse printed along X axis: 
<a href="https://i.sstatic.net/ko1pr.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/ko1pr.jpg" alt="Vase print; extruded ellipse printed along X axis"></a></p>

<p>Now, same ellipse in layered mode (seam side) printed along Y axis
<a href="https://i.sstatic.net/xaXJd.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/xaXJd.jpg" alt="Layered print; extruded ellipse printed along Y axis"></a></p>

CC BY-SA 4.0
2019-07-02T02:37:27.340Z
Please put photos in your question, not as links to external sites.
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2019-07-02T04:01:27.520Z
Do you know the lead screw's lead/pitch? What is your layer height? Made any calibration adjustments to steps-per-mm?
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2019-07-02T04:42:25.487Z
the lead screw is just M4 so i guess the pitch is 0.7 (according to http://www.metrication.com/engineering/threads.html ) and layer height is 0.3063. Didn't do any calibration adjustments.
Andrew Butenko
CC BY-SA 4.0
2019-07-03T13:44:54.087Z
it would help if we would know the model - is it a perfect cylinder or can you show it? Also, this is a cantilever printer, make sure that the arm does not raise or lower during printing.
Trish
CC BY-SA 4.0
2019-07-03T18:23:41.940Z
@0scar: How does 0.7×200 come up? If the pitch is 0.7 and there are 200 steps, it should be 0.7/200×200=0.7, not 0.7×200. But I'm skeptical that the pitch is actually 0.7. Does M4 mean actual M4 thread in this context, or just 4mm diameter with a metric thread profile shape but some larger pitch and possibly multiple starts?
R.. GitHub STOP HELPING ICE
CC BY-SA 4.0
2019-07-03T18:42:27.653Z
It looks like the period is 14-15 layers, which would be 4.2882-4.5945 mm based on the above-reported layer height.
R.. GitHub STOP HELPING ICE
<print-quality><troubleshooting><monoprice-select-mini>
Help diagnose Z-banding
Andrew Butenko
# Help diagnose Z-banding

(Asked by: username_0 on 2019-07-02)

The printer is ["Monoprice MP Select Mini 3D Printer V2"](https://www.monoprice.com/product?p_id=21711).

This is how my printed fan part looks like:

[![Printed fan part](https://i.sstatic.net/BG8lC.jpg)](https://i.sstatic.net/BG8lC.jpg)

These printers are notorious for their Z lead screw assembly (M4 bolt & nut) so I installed flex coupler and aligned the M4 bolt and motor shaft so that the wobble is minimal. It is still there, but I don't think this amount of wobble would produce something like what I experience. Please check out the [timelapse video](https://photos.app.goo.gl/XTdaZMjGvCgwsZ9W7) at the end.

I also tightened up Z guide rails (no rattle, very little slop)

Moreover the banding appears to be less pronounced and have alot greater period for vase prints [![Vase print; extruded ellipse printed along Y axis](https://i.sstatic.net/dJBLe.jpg)](https://i.sstatic.net/dJBLe.jpg)

(this is extruded ellipse printed along Y axis).
I tried:

1. slowing down print by 50 % - no effect on banding.
2. monitored hotend temperature with external probe on the heater block (-+5 °C)

The banding appears to be almost exclusively in Y axis direction; for example, the same ellipse printed along X axis:
[![Vase print; extruded ellipse printed along X axis](https://i.sstatic.net/ko1pr.jpg)](https://i.sstatic.net/ko1pr.jpg)

Now, same ellipse in layered mode (seam side) printed along Y axis
[![Layered print; extruded ellipse printed along Y axis](https://i.sstatic.net/xaXJd.jpg)](https://i.sstatic.net/xaXJd.jpg)

**Tags:** print-quality, troubleshooting, monoprice-select-mini
> **Comments:**
> **username_1**: Please put photos in your question, not as links to external sites.  
> **username_1**: Do you know the lead screw's lead/pitch? What is your layer height? Made any calibration adjustments to steps-per-mm?  
> **username_0**: the lead screw is just M4 so i guess the pitch is 0.7 (according to http://www.metrication.com/engineering/threads.html ) and layer height is 0.3063. Didn't do any calibration adjustments.  
> **username_2**: it would help if we would know the model - is it a perfect cylinder or can you show it? Also, this is a cantilever printer, make sure that the arm does not raise or lower during printing.  
> **username_1**: @0scar: How does 0.7×200 come up? If the pitch is 0.7 and there are 200 steps, it should be 0.7/200×200=0.7, not 0.7×200. But I'm skeptical that the pitch is actually 0.7. Does M4 mean actual M4 thread in this context, or just 4mm diameter with a metric thread profile shape but some larger pitch and possibly multiple starts?  
> **username_1**: It looks like the period is 14-15 layers, which would be 4.2882-4.5945 mm based on the above-reported layer height.  

---

## 1 answers

### Answer by username_3 on 2019-07-03. Score: 2 | Accepted answer

This differs from the traditional banding as observed from Z wobble induced banding as e.g. explained in [this answer](/a/5824).

Your banding patterns clearly seem to form diagonal bands, this is most probably a combination of the lead and the full rotation of the stepper. The most logical explanation is that the layer shifts as a whole in X-Y direction (when seen against the print height, this movement is concentric seen from the top). This means that the next layer is positioned over the previous layer in a concentric pattern. This hints to some sort of defect in your X/Y-plane assembly and should be investigated further.

This is difficult to visualize, but this sketch shows the issue for some layers:

[![Diagonal Z banding by concentric consecutive offsets](https://i.sstatic.net/5CzDk.png "Diagonal Z banding by concentric consecutive offsets")](https://i.sstatic.net/5CzDk.png "Diagonal Z banding by concentric consecutive offsets")

This could be related to the belts of the X and Y-axis, play on the drive pulleys, non-straight lead screw, guide rods with play, play in general, [Z-stepper alignment to the threaded rod](https://hackaday.io/project/14823-monoprice-select-mini-maximum-3d-printer-mods/log/51880-dont-go-wobbly-on-me-now), etc. Considering the amount of [Z-wobble fixes](https://www.mpselectmini.com/thingiverse/z-axis-stabilizers) shared by the unofficial MP Select Wiki, the best place to look for is the Z-stepper to lead screw coupling.

> **Comments:**
> **username_1**: It sounds like the lead screw might be bent (thus applying forces in the X and Y directions dependent on its rotational orientation) and like the Y axis belt may have more play/elasticity in it (or X if I read the description backwards).  
> **username_0**: Thank you @0scar! I think your diagnosis is spot on. I checked slop and belts on Y axis before but didn't consider that bed heating cable might snag underneath the rails thus impeding proper Y positioning. I wouldn't expect this effect to have periodic rather than random effect though. but the issue is almost gone after repositioning of the cable.  

---

