Introduction: How to Add a Laser Engraver to Your 3D Printer
I wanted to laser engrave a clock face for a magnetic clock I am building, but didn't want to invest in a laser engraver without knowing how much I would use it. Also the clock face is larger than most laser engravers allow. I have a CR-10 3D printer, which can be driven as a laser engraver, and has a 300x300mm workspace. I just needed to figure out how to mount and drive the laser on the CR-10.
After some research, I discovered you can drive most diode laser engravers from the PWM output of the part cooling fan. However, you can't just use the fan wires already connecting the printer control board to the cooling fan. You will need to power the laser separately and connect the laser PWM to the 5 volt input of the fan control MOSFET for it to work.
To connect the laser engraver to the printer you will need:
- Any 3D printer
- Laser engraver/cutter similar to this one
- 100 ohm resistor
- Connector for laser like this one
- 3/8 inch round pot magnets similar to these
- (2) M3 x 30mm and (2) M3 x 10mm screws
- 3D printed laser mount mount
To build a laser shield:
- Jtech Photonics Laser shielding (2) 12"x12" and (2) 12"x24" pieces
- 3D printed connectors for shielding
Step 1: Connect the Laser to the Power Supply
This will be specific to your printer. You will need to open the control box (plenty of videos on Youtube for various printers) and add connections for +12v and ground. If you have an Ender 24 volt printer, you can see how to add a 12 volt circuit here. You will need to route the power and ground to a connector near the hot end. I'm assuming that if you have the skills to attempt this project you are capable of routing the wire from the PSU to the hotend. Remember to turn the power off and unplug the printer.
Step 2: Connect the Laser PWM to the Cooling Fan MOSFET
This should work for all Creality boards and likely many others. Solder a wire to the exposed 5V part cooling fan control pin as shown. I've used this on the original CR-10 board, V1.1.5 and V2.2.1. Be sure to connect a 100 ohm current limiting resistor between the MOSFET and the laser. This will simulate the load of the cooling fan and protect the board. Also route this wire to your connector at the hotend.
Step 3: Connect the Laser
I wanted a sturdy, locking connector to be sure the laser stayed connected. I chose this connector
I cut one of the JST connectors off the end of the laser cable, and replaced it. I connected the matching connector to the wiring from the printer.
Alternately, you can cut one end of the laser cable and wire directly from the printer to the laser cable. I chose not to because I wanted to connect/disconnect the laser farther from the hotend.
Make the connections as shown in the picture. If you have a fourth wire, it's for laser temp and you can leave it unconnected.
Step 4: Print and Assemble the Laser Mount
The easiest way to mount the laser is to 3D print one of the files below and attach the magnets. This will hold the laser in place and work well. I have included both a side and top mount to choose from. Use the M3 x 10mm screws to connect the pot magnets to the mount and the M3 x 30mm screws to screw the mount to the laser just under the connector as shown. The laser will then ride solidly on the hotend of the printer.
The mounting will reduce the Y-Axis workspace by 20cm or so. I have a need to engrave the full size of the bed. I have designed a changeable mount to swap out the hotend and laser that also allows full use of the workspace. I'll share it in the future.
Step 5: Build the Shield
Laser light is very damaging to the eyes. Even a slight reflection can do serious vision damage at these powers. Always wear laser safety glasses. J Tech Photonics sells plexiglass laser shielding. I choose not to fully enclose my printer, so I built a portable laser shield to put in place when the laser is in use.
If you print on a mirror, remember to turn it over before using the laser.
To build the shield, order (2) 24x12 and (2) 12x12 plexiglass pieces. Print two corner connections, three stand offs, and four top corner connections from the files below. Use the the two corner connections to connect the two 12x12 pieces to one of the 12x24 pieces. Use the four top corners to mount the second 24x12 piece to the top of the other 3 pieces. Set the shield on the three standoffs. A little dab of hot glue will hold them all together.
Having the shield in place while you are using the laser will protect your sight and that of anyone that walks into the room.
Step 6: Learn to Engrave
This will take some practice. My advise is to start with the 30 day trial of Lighburn and then purchase it if you plan to continue. It's only $40 and well worth it. Don't waste your time trying to make the free tools or plugins work. Lightburn is the easiest starting point and it just works without a lot of hassle.
Lightburn has a nice "Focus Test" feature under "Tools" that can help you focus the laser. I have my BLtouch mounted with the laser engraver and it makes it easy keep the laser a consistent distance above the bed to keep the focus.
Start simple learn the speed and power you need for different materials with practice.