Having discovered the Norton White Tile method (NWT method) some months, I was very excited about the possibility to engrave on tiles and glass after painting them with the proper color spray. It was then that I had the idea to make a try painting and engraving a piece of transparent acrylic.
The type of color we can use for this purpose doesn’t matter, except if we want to remove it after the engraving process. A color solvent might damage the surface of the plexiglass. On the other hand, a water-based color can easily be removed by applying IPA, steam or hot water.
Burning the painted surface with the laser, the color is removed and at the same time, we have a permanent, relatively deep, engraving on the surface of the plexiglass.
Engraving transparent acrylic, leaving the color around it…
We can use isopropyl alcohol to clean the surface of the transparent acrylic from dust and residues and then apply the color spray. A source of light (a light bulb or the sun) from the back will be very helpful in order to be sure that the surface has been painted evenly.
After applying the paint and leaving it to dry, we are ready to make the engraving. As in every laser project, focusing on the laser lens is critical. In order to focus, I use the z-axis and this g-code: https://cdn.endurancelasers.com/wp-content/uploads/2021/09/g-code-example.txt
In the following example, I mirrored the letters in order to leave the color and the engraving at the backside of the plexiglass. By doing this it is not possible to scratch the color accidentally while cleaning the surface.
The material is clear acrylic 780x170x10mm and the settings I used were 70% power for the Endurance 10W “invincible” ( https://www.endurance-lasers.com/products/10-watt-laser-invincible-continuous-power ) at 1250 mm/min feed rate. The g-code was executed using Openbuilds CONTROL.
The following video shows the engraving process:
The sign is ready…
… and placed to the final spot, when it will be backlight using led strip…
(Super Mario at the two sides of the arcade cabin and at the front, with his brother Luigi, have been made with stencil following this process: https://endurancelasers.com/laser-cutting-of-a-masking-tape-stencil-with-a-diode-laser/ )
Engraving transparent acrylic, removing the color from it…
If we want to remove the color after the engraving, it will be easier to use a water-soluble one, which can be removed by applying IPA (93% is enough)
The settings for this example are the same as above (70% power, 1250 mm/min feed rate) and the color spray is chuck paint (light grey) which is water-soluble.
Applying IPA on the engraved surface, we can wait for a little and then we can take away the color with a clean piece of fabric, gently in order not to scratch the surface.
At the following links, are described 3 other methods for engraving on transparent acrylic from Endurance robots channel
Thanks a lot for your time and feel free to have a look at my Facebook and/or my Instagram profile, where I post only projects that I build!
Michail Gedeon
How to make a beautiful laser engraving on acrylic and glass