This technique for creating high contrast panels for electronics projects and prototypes using a laser cutter gives great results using cheap and easy to find materials. It’s really useful as an alternative or substitute for more expensive and harder to find laser engravable laminates like SureLase.
The product we use at work for laser engraved signs on products we ship, SureLase, gives great results, is super easy to use and available in a large range of colours. Its downside for non-commercial users is its price and the fact that you have to buy a large 1 x 1.5m sheet. It’s also not as versatile as a plain piece of 3mm acrylic, you can’t make other parts out of it since that’d be a waste.
Here are some photos of some items made with a different method, achieving similar results and using just 3mm white acrylic and a black wax crayon. It’s easy, fast (though not as fast as SureLase) and looks dead smart.
Example electronics project facia, missing the pot and switch to finish it off:
Some inserts to be installed inside some industrial panel mount LEDs made by Chint:
A cog from a mechanical clock designed by Alan Parekh before it had it’s final wipe down:
Process pictures and descriptions after the break…
So…. How? Here are the steps:
1) Etch your design onto a piece of acrylic. I used 3mm white acrylic. After etching, depending on the colour you used, the contrast between etched and non-etched is poor to okay. Here’s a photo of the example front panel after etching. Pretty bad huh?!
2) Blow out any residue from the etching. Some of the fumes from the etch spread across the surface of the acrylic.
3) Scribble on the etched acrylic with a wax crayon (yes really), dragging it back and forth perpendicular to the direction of the edges of the etched areas. This method will only work on thin lines up to about 2 or 3 millimeters. As you pass the crayon against the sharp edge of the trench cut by etching, some of the crayon gets left behind, filling the etched trenches.
Here’s a photo of the same front panel facia after plain black wax crayon’s been used on it. Messy!
And one of the clock gear after a good scrub with a crayon:
4) Wipe with a taut white spirit soaked tissue.
Apply white spirit to a tissue stretched over a finger or a block of wood, or laid out on a table. Rub the messily waxy side of the acrylic against it to remove most of the excess. It needs to be white spirit. I tried IPA without as much success, and other solvents (acetone for example) may damage or cloud the finish of the acrylic.
5) Apply white spirit to a piece of plain white paper on a flat surface. Rub the acrylic part against the paper to remove the final bits of wax not in the etched grooves. Doing it this way, the majority of the wax is removed by the tissue, rubbing on the paper allows you to rub harder, removing those stubborn bits.
One of the Chint LED inserts having its final scrub:
6) Bake ‘em
As they are, the laser etched grooves are filled with wax, the wax a level cap over the etched areas. By melting the wax slightly it will settle into the corners and imperfections of the laser etched surface (which if your etch step size is rough, are quite great) and stick better while dipping slightly at the surface, protecting it from anything scrubbing over it.
Throw your etched and waxed acrylic pieces into an oven at 40 Celsius (~104 Fahrenheit). If your oven doesn’t go this low, turn it up high and leave the door open. Warm them for about 20 minutes before removing.
7) Give them one last wipe with white spirit on paper, or IPA if you have it, then call them done! If wax settled and left gaps on any wider etched parts, refill with wax, clean then reheat.
I found that this process gave good results down to etch paths 0.5mm wide. See the (Hz) on the electronics panel example, the definition is great, even so small.
And here are some finished pictures. A massive thank you to Steve for suggesting I have a play around with filling etches with wax and letting me play around with it at work!
Finished insert for Chint panel mount LEDs:
Etched inserts in situe. My camera took a dislike to the differences in light levels, hence the poor photo. They looked a lot better than this in person…
A finished example panel for an electronics project:
And finally, one of the gears from a geared clock project: