Add motorized Z axis on my chinese laser

I have a chinese laser, which I bought a year ago or so, without Z-axis. I built a manually adjustable bed with 3d printed pieces and metal parts.

Now I would go further to motorize my bed.

I have a RuiDa controller, and already have a Nema-17 stepper motor and a TB6600 Stepper Motor Driver.

From here, I’m stuck with the wiring part. I don’t know how to wire the stepper motor driver to the power supply (if I have to), and the nema 17 to the stepper motor driver.

Can someone help me with this please ? I add some pictures of my installation and hardware.

Thank you

I think this should get you started. I took the model number off the stepper driver for specifications. Hopefully it’s correct.

S1 - suggest you match to other motors

Assume 2.0A - you could start lower if you wanted to reduce heat
S4 On
S5 On
S6 Off

DIR- Z-axis DIR on controller
DIR+ Z-axis +5V on controller
PUL- Z-axis PUL on controller
PUL+ Z-axis +5V on controller

B- blue on stepper
B+ red on stepper
A- green on stepper
A+ black on stepper

GND ground on 24V supply
VCC +24V on 24V supply

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Thanks a lot Berainlb, I will keep those informations.
Here is the link where I bought the stepper motor driver, to verify: Aliexpress - Stepper Motor Driver

You said 24V supply, so it’s on the grey one on the left? Not the blue one, right? And as I see there is not a lot of available space for new wires on it. I think it’s actually mainly used for the rotary motor (with a switch (Y-Axis/Rotary) on my machine). Should I get a different/extra power supply? Sorry, I’m very not aware of all those electrical things.

Thank you !

Yes. Definitely not the blue one. Blue one is LPS - Laser Power Supply used to excite laser tube.

This should be powering all the components of the machine other than the laser tube. So your controller, all other steppers, etc.

You could get another supply. That would work but likely not necessary and create other challenges. Check how the other steppers are connected to power. You should be able to double up those wires.

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Ok, thank you very much for your help. I hope to test it soon.

There is no risk to “over-charge” the power supply if I double-up the wires in the same connexions?

You could confirm the power supply ratings and add-up the current requirements for all your equipment but generally this will be fine and it’s likely the same power supply is being used for machines that have motorized Z and machines that do not. You could replace the supply if it proves to be underpowered.

I don’t know if the Z stepper is kept engaged the whole time the machine is on. If it’s not then this isn’t likely to be a concern since Z is infrequently used and when used not concurrently with other steppers. Even if it is kept engaged it’s mostly just holding.

You could reduce current to 1A to start which might not be a bad idea anyway. Then increase it if you’re not getting enough torque. For Z this shouldn’t be a big issue.

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Thank you again Berlainlb. I followed your instructions and did the same settings on the side of the controller. And it works :slight_smile:

Now I have a “last problem”, as you can see on this video, the belt is not moving, it’s like it’s missing teeth on the GT2. Do you know what can I do to fix this? The belt is new and tightened, and all of my pulleys have 20 teeth.

Video of laser bed

Edit: It’s about belt tension. I need to 3D print a belt tensioner somehow…

That’s great you got the wiring worked out!

As for the issue… I can’t see your whole belt path in the video but it looks like you have very little tooth engagement between each pinion and the belt. Between that and belt tension issues the belt is likely slipping on the stepper motor pinion.

You could try to address this a few different ways:

  1. Get larger gears. This would allow more teeth to be engaged. Might be useful at the corners.
  2. Reroute the belt so that angle to each gear is increased.

For tension, you probably want a tensioning pulley that is adjustable where you can vary the amount of tension being applied.

Something like this:

The red circles represent potential locations for tension adjustability.

You could also use a combination of larger gears and increased angles.

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Thank you very much for your explanation. I’ll think about that, even if it’s a bit strange, as it worked before just with the 4 corners, when I changed my Z-axis manually.

You’re likely moving much more slowly when doing it manually.

You could try dramatically decreasing acceleration and speed to see if that helps.

Also, make sure you don’t have any binding or irregular friction somewhere in the mechanism.

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Here is my new “setup”. It works good, thank you again for your help.

Looking good! Glad you’ve got a working solution now.

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