When I received this laser engraver, I read warnings against attempting to engrave transparent or metallic materials. Good thing I'm not a smart guy, so I decided to try it anyway. It had to work. Guess what? Turns out it works a treat!
I decided to try and make LED illuminated signs, kind of like those "exit" signs you see places. The principle is simple: light passes through the sheet, and wherever there are bumps, engravings or scars, light will exit.
I bought two sheets of 300x300x2mm styrene acrylonitrile. They are easy to cut and come with a protective film on each side. This is a good thing, because these guys scratch easily. The sheets were cut by tracing the desired route with an utility knife, and then giving it a friendly whack to split the board.
Here's the sheet with the protective film on each side intact.
Here you can see the transparent sheet (without the protective film) being engraved. It's from another project, but shows the job being done. It had to run at a low speed in order to have an impact on this particular material.
Dickbutts aside, here's the first successful project I made. A square blue LED is superglued in an bottom insert, flush with the rest of the board. The edges are quite illuminated, this can be prevented either with electrical tape, or painting the edges with a solid colour. I think it looks cool the way it is.
Here's the CR2025 battery wedged between the LED's cathode and anode pins, which conveniently serves as a rest. The internal resistance of this battery is so high that a current limiting resistor is not required.
By adjusting the focus and the burn time, I was actually able to cut through the 2mm styrene acrylonitrile completely. However, while experimenting with this I stumbled across something unexpected - but I'll save that for a later post. (How's that for a cliffhanger ending?)