Turning my 3D-Printer into a Laser Engraver 1: Goals

This project is mostly driven by a desire to expand my CNC-capabilities as cheaply as possible.

I already had an Anet A8 Printer (as far as I know, the cheapest one available on the market when I bought it. Spot the pattern!) and figured I could hijack the frame/motors/controller and turn it into a laser engraver too. When engraving, just stick the laser to the side of the print head, use the extruder motor channel to power the laser instead and don’t heat up the bed or the nozzle.

For the laser, I did some googling and eventually felt confident enough in my understanding that a ‘good enough’ engraving laser probably has between 200 and 400mW of power and a wavelength of either 650 or 405nm. What the advantages of either are over the other, I couldn’t hazard a guess. I shopped around Aliexpress and settled on one (specifically this one, but the details hardly mater, per my understanding).

It arrived, I tried to figure out whether I needed to supplement it with resistors/capacitors, couldn’t find anything and decided to go for the scientific approach: Just hook it up to power and see if it burns my house down.

Testing the laser on some wood

It didn’t, and I eventually figured out the (surprisingly large) focal length to very, very mildly burn a piece of compressed wood. After engraving a few black lines, I tried to set the wood on fire and was almost disappointed it didn’t work. I then tried to burn a piece of paper, but it didn’t even turn dark. This made me feel safe enough to check with my finger, and I couldn’t even feel anything. (Disclaimer: Do not do this if you value your fingers. It’s a stupid thing to do, I’m just not a very smart person.) (DISCLAIMER 2: Even if you do subscribe to the same ‘meh’-approach to bodily harm, NEVER EVER EVER look into the laser). This next led me to the cool discovery that I could still engrave some washable surfaces, even if they were white and did not burn by themselves, by putting a thin layer of black acrylic paint over it, burning it, then washing the paint of.

Now I knew the laser would work. From here, I needed to:

– Mount it to the printer
– Properly control it

The first step would probably be very easy (the laser didn’t even turn warm at all, so there’d likely be no need for cooling), however, I deliberately made the second part hard on myself: I was going to write the slicer, the software which turns a source file into instructions to the printer/engraver, myself. I could, of course, just use something like loksters laser engraving plugin for inkscape, but that wouldn’t be very in terms of building it myself. So these are my goals for my software:

  • Standalone GUI, written in Qt/Python
  • Support black and white bitmaps as source files first, add vector later
  • Preview of resulting image
  • Allow for deep configuration of every parameter, making the tool usable for any 3D-Printer
  • Possible future features would include automatic image processing, such as upscaling in various styles, grey-scale engraving, diverse hatch modes… (Most of these will probably only be added when/if I need them myself)

My ideal goal would be to have this ready by Christmas, possibly even get one or two gifts out of it. This is not very realistic due to work and studies, but I’m very motivated, so who knows.

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