Full Spectrum MLE-40 4th Gen Cohesion3D LaserBoard Install

Full Spectrum MLE-40 4th Gen Cohesion3D LaserBoard Install

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This guide will walk you through the process of installing the Cohesion3D LaserBoard into a Full Spectrum MLE-40 4th Gen Laser.

Here are the components you’ll need:

Here are the tools you’ll need:

  • Small flathead screwdriver
  • Wire strippers
  • Wire crimpers
  • Multimeter

There were two different controllers and three different configurations used in this model and we’ll cover each one as we go.

This is the first controller used in the early models and comes in two pieces with connectors that plug directly into the board. You will only be able to plug the stepper motors directly into the LaserBoard, the rest will need to be connected with the screw terminals.

If you have this controller, proceed to LIMIT SWITCHES below.

FSL Control Board

This is the second controller version with two possible configurations, one with the current controlled by the potentiometer dial on the panel and one with the current controlled by software. They generally left the potentiometer mounted in these units with the cable unplugged and laying on the bottom near the laser power supply. All you’ll need to do is unplug the wire going to your old board and plug the one laying free in its place, as shown below.

FSL Control Board

Simply swap these two plugs to enable the potentiometer.

Since the laser has an ammeter, potentiometer dial, and a test fire button, setting the maximum power to 15-17 milliamps should be simple. With the lid closed and all safety interlocks engaged, press the test fire button, dial the potentiometer up or down until your ammeter shows between 15mA and 17mA. You can now leave the potentiometer set in this position and in LightBurn 100% power should equal 15-17 milliamps. All power setting can then be controlled via the settings in LightBurn.

Potentiometer Control

The connector ends on the wires are cut off on this model controller, this is fine, since the LaserBoard has screw terminals for the stepper motor wires and laser firing control wires.

Make sure to note the X and Y cables and place the wires accordingly.

Y-axis and X-axis

Note that your unit may also wire like this.

Y-axis and X-axis on LaserBoard


In order to properly mount your limit switch wires, you’ll need to use the parts in our Connector Pack for Cohesion3D LaserBoard. These are easy to install.

Your limit switch wires are going to be the thicker red, blue and two black pieces all in the same wire loom. The black wires should go to the center pins, which is ground and the colored wires will go to the signal, NOT the V+. The red wire is for your X-Axis switch and the blue wire is for your Y-Axis switch. These switches are normally closed, and if you would like to pair them, you can use a meter to check continuity. When the switch is triggered, the circuit becomes open and that’s what signals the LaserBoard that it’s in the homed position.

We recommend using a multimeter to pair the wires so any future troubleshooting will be smoother, but is not necessary if you place the black wires in the center pins (ground) on both plugs since the grounds are all tied in. You’ll need to strip the ends of the wires, crimp them in place and then insert them into the plug. Note the position of the clip going into the plug.

Limit Switch Connector

Cut the bared wire down to a length that allows it to match the size to the crimp.

Crimping wire

Carefully insert them into the plug housing. Make sure to place them exactly as we have them here, as the orientation matters.

Crimping wire


Endstop connectors

The Cohesion3D LaserBoard comes with a high quality (UL Listed) power supply that eliminates the 24v and 5v requirement from the machine’s existing laser power supply and requires only two wires, the laser fire control and ground. You can remove the 24v and 5v wires altogether as shown or you can use them for your lighting and diode pointer if your unit has one.

Do not attempt to utilize any power from the LaserBoard except otherwise noted in the LaserBoard documentation LaserBoard Air Assist Control. Connecting anything else can damage it.

The only two wires needed are for controlling the laser firing. Connect L to the screw terminal shown. It’s the one that lines up with the label PWM behind it. (This is the “Pulse Width Modulation” power control.) The Ground is the other connection you will need. In the photo below you’ll notice that L is a green wire and Ground is a yellow wire. Don’t rely on wire color though, always confirm which colors is connected to L and GND on the LPSU.

Using the 5v out on laser power supply to power the diode pointer is perfectly acceptable since that was the default setup, but there is no longer a need for these wires to connect into the controller and caution is advised to keep them isolated from shorting. The black wires were already cut from the ground on this machine, but you’ll need them if you choose to use the laser power supply for lighting or the diode pointer.

To mount the LaserBoard we used one existing hole, then marked and drilled the other three as shown.

Mounting Plate

Here’s the final install. Spacers were used so there is enough of a gap between the LaserBoard and the mounting plate so that the back of the board is not touching the plate.

LaserBoard mounted

Once you have the hardware portion of the install complete, you’ll need to make edits to the config file that is on the SD card. The cutting/ etching area for an MLE-40 is larger than a K40, so you can edit alpha_max and beta_max appropriately. Values will probably be close to 370 for alpha and 235 for beta.

For additional support with config changes please visit our Support Forum.