Attention ! This post is only valid for FluidNC K40 shields with a version >= 8.xx
This shield is optimized for K40 laser cutters but it works with all types of machines including diode lasers
You can buy this plug & play shield here : Link
First step is to install Lightburn (Link)
It is very important to set it exactly as I ask in the post above.
Once Lightburn is installed, please refer to the correct section of the post depending on your machine equipment. This post seems long, but it takes into account all the possible configurations of the K40s. You will only have one case to perform on your machine.
Important note : if your machine is very old, you could have an orange motherboard with a 6 pins power connector. My shield will be compatible with this kind of machine, but you’ll have to rewire a little bit this connector as +24V and GND are swapped compared to all new motherboards (green & purple ones). Please contact me if you are equipped with this orange board.
Case 1: Machine with digital panel, equipped with a ribbon cable – Click here
Case 2: Machine with digital panel and not equipped with a ribbon cable – Click here
Case 3: Machine without digital panel, equipped with a ribbon cable – Click here
Case 4: Machine without digital panel and not equipped with a ribbon cable – Click here
Case 1 (digital panel – ribbon cable)
In this configuration, the installation of the FluidNC K40 shield is plug & play.
No need to modify any connectors.
Old boards :
New FluidNC K40 Shield :
Simply disconnect the 4 cables from the old cards and reconnect them to the new card, keeping the color code. Your machine manufacturer may have used hot glue to secure the connectors. Just carefully remove enough glue to get the connector out of the old boards (don’t try to remove all the glue).
For the orange connector (the one that was connected to the digital board under the hood), you will have to take the wires associated with this connector out of the cable sheath. The goal is to have enough slack to be able to connect to the new shield.
For the gray connector (the one that connects to the Y axis on the new card), you must put the red wire of the cable towards the bottom of this photo (in other words the red cable must be on the side of the connector Z axis)
For the yellow connector (ribbon one), you must lift the white connector on your FluidNC K40 shield to open it, then insert the metallic contact ribbon cable towards the outside of the board (therefore upwards in the photo above), then close the connector
Now connect to connect the USB cable (micro USB format) to the processor of the new board (electronic component in the middle of the board)
Case 2 (digital panel – no ribbon cable)
In this configuration, the installation of the FluidNC K40 shield is plug & play.
No need to modify any connectors.
Old boards
New FluidNC K40 shield :
Simply disconnect the 5 cables from the old cards and reconnect them to the new card, keeping the color code. Your machine manufacturer may have used hot glue to secure the connectors. Just carefully remove enough glue to get the connector out of the old boards (don’t try to remove all the glue).
For the orange connector (the one that was connected to the digital board under the hood), you will have to take the wires associated with this connector out of the cable sheath. The goal is to have enough slack to be able to connect to the new shield.
For the blue and gray connectors (those that plug into the X and Y axes on the new board), you have to put the red wire of the cables towards the bottom of this photo (in other words the red cable of each connector must be on the side of the Z axis connector)
Now connect to connect the USB cable (micro USB format) to the processor of the new board (electronic component in the middle of the board)
Case 3 (no digital panel – ribbon cable)
In this configuration, it will be necessary to wire a 5-way Dupont connector (Amazon link).
No soldering required to install your FluidNC K40 shield.
Old board :
New FluidNC K40 Shield :
Simply disconnect the 3 cables from the old board and reconnect them to the new board, keeping the color code. Your machine manufacturer may have used hot glue to secure the connectors. Just carefully remove enough glue to get the connector out of the old boards (don’t try to remove all the glue).
For the gray connector (the one that connects to the Y axis on the new card), you must put the red wire of the cable towards the bottom of this photo (in other words the red cable must be on the side of the connector Z axis)
For the yellow connector (ribbon one), you must lift the white connector on your FluidNC K40 shield to open it, then insert the metallic contact ribbon cable towards the outside of the board (therefore upwards in the photo above), then close the connector
It is now necessary to wire the brown connector on the left of the photo.
See section below : Wire the Laser Management connector
Now connect to connect the USB cable (micro format) to the processor of the new card (electronic component in the middle of the card)
Case 4 (no digital panel – no ribbon cable)
In this configuration, it will be necessary to wire a 5-way Dupont connector (Amazon link).
No soldering required to install your FluidNC K40 shield.
Old board :
New FluidNC K40 Shield :
Simply disconnect the 4 cables from the old board and reconnect them to the new board, keeping the color code. Your machine manufacturer may have used hot glue to secure the connectors. Just carefully remove enough glue to get the connector out of the old boards (don’t try to remove all the glue).
For the blue and gray connectors (those that plug into the X and Y axes on the new board), you have to put the red wire of the cables towards the bottom of this photo (in other words the red cable of each connector must be on the side of the Z axis connector)
It is now necessary to wire the brown connector on the left of the photo.
See section below : Wire the Laser Management connector
Now connect to connect the USB cable (micro format) to the processor of the new card (electronic component in the middle of the card)
Wire the Laser Management Connector
You must skip this section if your machine was equipped with a digital panel.
In this case, go directly to the connecting to a computer section of your Shield FluidNC K40.
This step is therefore only necessary if your machine was equipped with a potentiometer for adjusting the power.
There are three possible power supplies for a K40:
Type 1 (Green connectors)
If you have this power supply (and no digital panel), disconnect the wires connected to the L (twice) and IN slots
You must now connect the power supply and your FluidNC K40 shield as follows :
L of the central connector of the power supply on ENA (L) of the new board
IN of the central connector of the power supply on PWM (IN) of the new board
G from the middle of the central connector of the power supply to GND of the new board
Type 2 (White connectors)
If you have this power supply (and no digital panel),
Leave the K-/K+ connector connected. There is only one wire connected to this connector. Follow him to the hood of your machine. Cut it as close as possible to the hood of the machine. We will call this wire L
Leave the G/IN/5V connector plugged in.
- Follow the IN wire that goes to the hood potentiometer. Cut the wire the closest possible to the potentiometer. We will call this wire IN
- Follow wire G that goes to the hood of the machine. Cut the wire the closest as posisble to the hood. We will call this wire G
You must now connect the power supply and your FluidNC K40 shield as follows :
Wire L of the K-/K+ connector of the power supply on ENA (L) of the new board
Wire IN from the G/IN/5V connector of the power supply on PWM (IN) of the new board
Wire G of the G/IN/5V connector of the power supply on GND of the new board
The 5V wire of the G/IN/5V connector does not matter. You can delete it if you wish. If you keep it, be careful to insulate it well.
Type 3 (black case – in general for laser > 50W)
If you have this power supply, my FluidNC K40 shield can be installed.
However, contact me so that I can guide you through the installation!
Connecting your FluidNC K40 shield to a computer
Connect the USB cable from your PC to your ESP32
Then, in Lightburn, click on the “Console” tab in the right column. You should see something like :
Now right click on the “Devices” button in the right column.
This will restart the USB/Serial connection between Lightburn and the ESP32.
You should see indications similar to the one below on the console:
If so, your computer and laser cutter connected as intended.
At this stage, you probably have errors on the Lightburn console
(Alarm 14, Alarm 1 or/and error 8). It’s normal.
You can proceed to the next steps.
Otherwise, check carefully:
- That the USB connection speed is correct (Edit/Device Settings): it should be on 115200 bauds
- That the DTR control is activated (Edit/Device Settings)
- That your USB cable is a data cable and not only and charging cable and that its length is below 80cm
It is also possible that the USB driver is not compatible with your ESP32.
You should then download and install the right version by going here :
https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers
Direct links :
For windows : CP210x Windows Drivers with Serial Enumerator
For MacOS : CP210x VCP Mac OSX Driver
If that still doesn’t work, it is possible that you have multiple devices on your PC that use the COM ports.
Go to your computer’s device manager (Windows key + R and enter devmgmt.msc)
Look for COM and LPT devices
Note the number of the COM port associated with the Silicon Labs CP210x driver installed just before and check that Lightburn is using the same COM port:
Réglage de l’axe Z :
Very important: if you have purchased your FluidNC K40 shield with 3 or more drivers but you do not yet have a motorized bed / Z axis, you must absolutely deactivate the Z axis homing.
Otherwise your machine will not work.
To disable the Z axis, enter the following commands, one at a time, waiting for an OK response between each command:
$axes/z/homing/cycle=0
$cd=config.yaml
$reset
To re-enable Z axis homing, enter the following commands, one at a time, waiting for an OK response between each command:
$axes/z/homing/cycle=2
$cd=config.yaml
$reset
If you have a Z axis / motorized bed, go to this article section “Z axis adjustment” to adjust it (link)
First start of your FluidNC K40 shield :
If you have followed my instructions to the letter, at this point your machine is not yet powered on -> check that the machine is not powered
Position the laser head in the center of the work area by hand
Turn on the machine
Be prepared to turn off the power to the machine if the head does not move in the correct direction in the next step.
Click the HOME button in lightburn
Normally, the head should go to the upper left corner of the machine, then come back 5mm on both axes towards the center, then go back towards the corner, then come back one last time 5mm on both axes towards the center (so 4 steps in all)
If there is any error in the console / the slightest warning, or you do not see an OK in the lightburn console, the HOME did not work.
It is essential to solve the problem before going further
You can get help from this article (Link) – If despite the explanations in this post you can’t solve the problem, contact me.
Once HOME is successful, you can use your machine with Lightburn!
Bravo !!
At this point you have a K40 with brand new electronics able to work with Lightburn, a motorized bed and lots of new features!
Check that you have the latest firmware and configuration file by reading this article: link
Remember that after powering up your machine, the shield cannot know where the head is.
It is therefore essential to launch a HOME via Lightburn each time you turn on your machine!
You still have to learn how to use Lightburn in detail: link to the manual
Link to the STL to print the shield support : Link
Connecting an air assist :
If you want to connect an air assist, you can follow the schematics below.
Connections on the shield are on the green connector (no polarity)
Link to relay (no affiliation)
Please make sure that you have configured Lightburn as per my instructions (M7 instead of M8 to drive the air assist relay in Edit / Device settings)
Z & A axis wiring :
If your stepper motors are making strange noises and shaking, it’s either due to too much load (too much resistance for example) or more likely a different pinout from the stepper motors you purchased. Indeed, there is no standard, and two NEMA17 motors for example, can have different wiring.
For reference, my board is wired as follows.
You must connect the two outputs A (A1 and A2) of my card to the inputs A (A and A_stroke) of the motor. Ditto for outputs B (B1 and B2).
More information can be found in this post : Lien
Hi, can I connect air assist to this board?
Hi Dean,
Yes for sure.
The green connector at the bottom left part of the board is there for that purpose.
It allows max 24V voltage. If you want to drive a 110 or 220V air pump, no problem, you just need to add in between the board and the pump a relay like this one
Then the relay is driven by the M7 command. If you are using Lightburn you just need to configure Lightburn in the device settings to use M7 and not M8 for air assist.
Best,
Cédric
Great.
Do you have a tutorial, wiring diagram or link how to connect this, with a relay for 240v air pump.
Regards, Dean
I have added a schematic in this post 😊
Hi. I have a couple of questions.
1st, what stepper drivers are supplied with this board?
2nd can I control air assist, water pump, and have a water flow detection / auto stop configured?
3rd can I buy the 4 stepper board and only use 2 channels to start, bringing the others online later.
Thanks
Hi Adrian,
Thanks for your interest !
For your 1st question, the board is delivered with DRV8825 drivers, calibrated on my own K40 before shipping.
2nd : you can control air assist with the board (see the bottom of the post explaining how to install the board). You could as well connect your water cooling on the relay, but I strongly don’t recommend it ! Water cooling has to be always ON, which is not the case of air assist. for Water flow detection, you can connect still connect it to your PSU to forbid laser firing or/and to the FluidNC board to trigger specific action like pausing the job.
3rd : yes for sure, when I deliver a 4 stepper version, I calibrate it, check all motors, but I configure only 2 drivers in order to work with stock K40. Then you can enable Z and / or A axis whenever you want