Days 3-5: My laser works!

My first (successful) engrave!

The past few days of working on the Etch-A-Sketch laser engraver were extremely long. I'm running a bit behind on my original schedule, however this is perfectly OK as I was already planning on finishing well before this project was due.

I don't wish to bore you with the details of how I spend days 3-5: staring at the computer screen, spending hours trying to figure out why something didn't work. I will instead describe all of my major exciting steps taken during this time, and show the rest of my process from turning the barely functional 3D printer into a mostly functional laser engraver.

I ended day two focusing on building the mount for the laser and bed level probe (calculates the proper distance that it should go in the Z (up/down) direction). The first two designs I built for the mount were not functional due to flaws I overlooked, however the third one works great! Once this project is done, I will try to release the .stl (3D) files in a way that properly gives credit to the original creator.

The 3D printed mount for the laser and probe.

After everything was set up, the next step was to wire the laser to the power supply and motherboard. The power supply's job is to convert the alternating current from the wall to direct current (which most appliances run on). It also drops the voltage from 120V to 24V, in this case. The motherboard is the brains of the laser cutter--it uses power from the power supply to interpret all commands by the user, move the motors, and send feedback is something is wrong.

The first part of wiring was a bit stressful, but extremely fun: I gutted the 3D printer! it no longer needs many of its original components, and ripping them out was satisfying. I took out the power cords going to the extruder (part that spits out plastic), and the heated bed. It also no longer needs the thermistors (digital thermometers to measure parts of the 3D printer that are now useless).

The engraver home screen without thermistors plugged in. Apparently it's -14 degrees!

Because 3D printers need very specific cooling abilities--they not only have to safely melt the filament at extremely hot temperatures without damaging the heat end's surroundings, but also need to properly cool filament as it hardens--they always contain multiple fans that the motherboard can carefully control. The input for controlling fan speed is the exact same for controlling laser intensity, and theoretically one could swap out the connector to the fan for the connector to the laser to successfully engrave. However, for my purposes this was a lot more complicated. The original 3D printer runs in 24 volts, and the laser I purchased runs on 12V. This means that if I plugged the laser into the motherboard's fan port, bad things could happen. I'm not sure about the specifics, but the Wikipedia page for Overvoltage seems pretty intimidating...

To make the 12V laser run on 24V, I had to use a buck converter--which steps down voltage in a certain direction. I used this video and a pretty fancy buck converter to do this. Because I'm not the best at it, I used my brother, Jared "Sausage Fingers" Goodman to help with soldering in the final stages of wiring.

Sausage Fingers Goodman

Once wiring was done, it was time to fire up the laser engraver! After running some more tests and re-calibrating to make sure nothing was broken or would unintentionally catch on fire, I recorded the Z height I was using and focused the laser on a thin piece of balsa wood. It's important to record the Z height the laser is at before focusing it as it can become out of focus at different heights (more on this in a later post).

Turning on the laser for the first time!

After that, I used Inkscape and Jon Schone's video to generate gcode (special manufacturing commands) so the engraver could make a design. Although I could rant about the problems I encountered with this software in an entire separate blog post, it would make me instantly reach the maximum space on my Google account. I won't release official tips for using Inkscape until I have a more in-depth chance to mess around with the software and engraver. I'm still learning, after all!

Here are the inital designs I have made with the laser engraver! Super happy with how everything is turning out, even though there are still a few kinks--I'm trying to find the best way to calibrate the engraver so everything is straight and centered, and to also send gcode commands that create an arc in the desired path traveled. Right now, the firmware is not accepting gcode commands for arcs (hence why all the details in the designs below are straight or diagonal lines). This is an extremely weird bug that will require more research to solve.

Victory! The text is a bit crooked relative to the sheet, and I made some progress with fixing this issue on the proceeding designs.

Designed with Illustrator and a tutorial from STE Bradbury Design. Thanks to my graphic design teacher, Danielle "Grandma" Troy for showing me the ropes with Illustrator.

The name for Sausage Fingers' robotics team.

Plans for the near future:

-Finish wiring for the rotary encoder (Etch-A-Sketch knob).

-Write code to hook up the rotary encoder to Octoprint, the software that sends information about where/how to travel to the printer. This will all be done through the Raspberry Pi.

Plans for the distant future:

-Fix the issue with the laser not moving concentrically.

-Find the best method for making sure the wood is always aligned with the X and Y axes.

A fun 5G fact:

-The difference in speed of 5G compared to other network generations is truly insane. It's average speed is 500x faster than 2G's (pre-iPhone, think back when the Motorola Razr and Blackberry used to be cool). It's maximum speed is 10x faster than the latest generation of 4G.