I wanted to add a laser engraving/cutting module to my Wanhao Duplicator i3 v2.1, without losing its ability to 3d print. I had determined to drive the laser with the excellent Lightburn software and, in order to do this, I had to change the firmware on the Melzi board from the odd version of Repetier used by Wanhao to Marlin, thus allowing full integration with the Lightburn software. I bought a 3.5w laser module from Endurance Lasers, a reputedly reliable source with good customer support and, most important of all, simple electronic connections.
This Instructable shows how I achieved my aim.
Step 1: Physical Connections
The Endurance Laser module comes with a whole range of mounting holes pre-drilled and threaded in the outside casing. The task is to secure this to the lower fan mounting on the Wanhao. I simply drilled appropriately spaced holes for M3 nuts and bolts in a length of 10mm x 10mm aluminium angle, mounted the bracket to the laser module and then bolted the bracket to the fan mount. This only takes a few minutes and provides a secure, reversible mount for the laser which means, of course, that the original fan can be reinstalled in an equally short time.
Step 2: Electronic Connections
The Endurance Laser can be powered by the 12v supply to the Wanhao Duplicator’s cooling fan and, as this provides a controlled Pulse Width Modulation supply, allows the TTL connection of the laser to be very simply wired too. As can be seen in the photograph, the cooling fan connector is wired to the laser positive and negative wires and the white TTL lead on the laser to the positive wire on the laser too. This simple wiring allows full control of the laser intensity through the cooling fan control which, as you will know if you have a Wanhao i3, normally controls the “percentage” of the fan’s power that is being applied. No other electronic connections are necessary, the amperage and current of the Wanhao being adequate to power the 3.5w Endurance Laser.
Step 3: Software and Firmware
Having downloaded a trial version of Lightburn to do both the design and laser control, it was discovered that this would not work with the unusual version of Repetier that Wanhao install on the i3. In fact, Lightburn will not currently work with any kind of Repetier. I wanted to keep the functionality of the 3d printer so I needed a firmware that would both integrate with Lightburn and the Endurance Laser and also perform 3d printing. The answer was Marlin.
A version of Marlin was downloaded from Github and an attempt made to upload it to the Melzi board on the i3. At this stage, it became obvious that there was no bootloader on the Melzi board, so the Arduino IDE was used to burn one. Connecting the Arduino to the Melzi board was fiddly but eminently doable and, with the reset jumper firmly installed on the printer, the bootloader flashed over in seconds. With the bootloader burned on, flashing the Marlin version was easy and finished in short time.
I would add here that if you are content to use some of the different free software available to run your laser, such as Inkscape for design and the excellent Endurance or JTech plugins to produce the g-code, the change of firmware is unnecessary. I wanted to use Lightburn so this was unavoidable, but very simple in the end.
Step 4: Results
The integration of the Endurance Laser and the Lightburn software allowed a novice like me to produce some nice things very quickly. The module engraves on most non-metallic surfaces and cuts wood, card and paper with no issues. The thickest I have cut so far is 3mm birch ply. Variable power is applied automatically by the Lightburn software and responded to readily by the laser module, so picture engraving is practical too.
The Wanhao runs beautifully on Marlin firmware, both as a laser cutter and as a 3d printer!