<p>There are a few options when adding an extra stepper motor, the usual upgrade is using a single stepper driver, driving 2 steppers either serial or parallel connected, or using 2 stepper drivers, this requires an extra stepper on the controller board (in that case one needs to replace the board; the standard board has the ability to control 4 stepper motors individually: X, Y, Extruder and Z).</p>
<p>The forces in 3D printing of moving the carriage along the various axes are relatively low, far less than e.g. a CNC machine where a spinning tool is pushed through a material. In 3D printing the nozzle hovers over the printing object connected to the print by a molten drop of filament, virtually no resistance. This implies that it is very unlikely to miss steps on one of the driven sides so that is becomes out of sync. Note that you can automatically tune the two sides if you have two steppers on separate stepper drivers and have a BLTouch (I'm using this on my CoreXY).</p>
<p>The two stepper motors push up a reasonably low mass for what the stepper motors can generate, certainly for the Z-axis as these are driven by lead screws. Driving a gantry with one stepper is <em>the</em> design flaw of the cheap-end printers, a timing belt with a single stepper works very well (I'm using this on my take of a Prusa i3 I designed), but must be mechanically tuned to be as straight in relation to the frame (if not, a test cube would look more as a 3D skewed cube).</p>
<blockquote>
<p>Anyhow, when two stepper motors are used, how to accurately synchronise them so that both screws on the Z-axis are and stay synchronised?</p>
</blockquote>
<p>Print a fixed distance leveling aid, see e.g. <a href="https://www.thingiverse.com/search?q=Level+x+axis&amp;page=1" rel="nofollow noreferrer">these</a> and level the X-gantry to the frame first, remove the levelling aids and then level the bed through the bed screws. The screws will not likely get out of sync, but if so, re-level with respect to the frame. Or, buy a larger controller board with more spare stepper drivers and automatically tune Z1 and Z2; be sure the bed is parallel to the frame then.</p>

CC BY-SA 4.0
2024-01-28T20:34:51.577Z
I didn't realize that a seperate controller creating Z2 was an option. I now upgraded to double Z on the standard v4.2.2 board with a Y-splitter cable basically having two Z1 axes. That probably makes it harder to synchronise, only mechanically, distance measurement I guess.
Bob Ortiz
CC BY-SA 4.0
2024-01-28T21:32:34.600Z
Indeed, just make sure they are both at exactly the same height with respect to the frame before powering the stepper motors.
0scar
CC BY-SA 4.0
2024-01-27T23:38:06.557Z
2024-01-27T23:38:06.557Z
0scar
<p>I upgraded two printers (Creality Ender 3 V2) with a dual Z-axis upgrade using an additional stepper motor. However, I realized that this could potentially still cause the two screws to be moved individually.</p>
<p>I figured that a mechanical dual Z-axis with a timing belt would have probably be a better upgrade instead of adding an additional stepper motor.</p>
<p>Anyhow, when two stepper motors are used, how to accurately synchronise them so that both screws on the Z-axis are and stay synchronised?</p>

<z-axis><stepper><belt>
How to accurately synchronise dual Z-axis when two steppers motors are used?
Bob Ortiz
# How to accurately synchronise dual Z-axis when two steppers motors are used?

(Asked by: username_0 on 2024-01-27)

I upgraded two printers (Creality Ender 3 V2) with a dual Z-axis upgrade using an additional stepper motor. However, I realized that this could potentially still cause the two screws to be moved individually.

I figured that a mechanical dual Z-axis with a timing belt would have probably be a better upgrade instead of adding an additional stepper motor.

Anyhow, when two stepper motors are used, how to accurately synchronise them so that both screws on the Z-axis are and stay synchronised?

**Tags:** z-axis, stepper, belt


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## 1 answers

### Answer by username_1 on 2024-01-27. Score: 1 | Accepted answer

There are a few options when adding an extra stepper motor, the usual upgrade is using a single stepper driver, driving 2 steppers either serial or parallel connected, or using 2 stepper drivers, this requires an extra stepper on the controller board (in that case one needs to replace the board; the standard board has the ability to control 4 stepper motors individually: X, Y, Extruder and Z).

The forces in 3D printing of moving the carriage along the various axes are relatively low, far less than e.g. a CNC machine where a spinning tool is pushed through a material. In 3D printing the nozzle hovers over the printing object connected to the print by a molten drop of filament, virtually no resistance. This implies that it is very unlikely to miss steps on one of the driven sides so that is becomes out of sync. Note that you can automatically tune the two sides if you have two steppers on separate stepper drivers and have a BLTouch (I'm using this on my CoreXY).

The two stepper motors push up a reasonably low mass for what the stepper motors can generate, certainly for the Z-axis as these are driven by lead screws. Driving a gantry with one stepper is *the* design flaw of the cheap-end printers, a timing belt with a single stepper works very well (I'm using this on my take of a Prusa i3 I designed), but must be mechanically tuned to be as straight in relation to the frame (if not, a test cube would look more as a 3D skewed cube).

> Anyhow, when two stepper motors are used, how to accurately synchronise them so that both screws on the Z-axis are and stay synchronised?

Print a fixed distance leveling aid, see e.g. [these](https://www.thingiverse.com/search?q=Level+x+axis&page=1) and level the X-gantry to the frame first, remove the levelling aids and then level the bed through the bed screws. The screws will not likely get out of sync, but if so, re-level with respect to the frame. Or, buy a larger controller board with more spare stepper drivers and automatically tune Z1 and Z2; be sure the bed is parallel to the frame then.

> **Comments:**
> **username_0**: I didn't realize that a seperate controller creating Z2 was an option. I now upgraded to double Z on the standard v4.2.2 board with a Y-splitter cable basically having two Z1 axes. That probably makes it harder to synchronise, only mechanically, distance measurement I guess.  
> **username_1**: Indeed, just make sure they are both at exactly the same height with respect to the frame before powering the stepper motors.  

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