This is 5% doing, and 95% mucking around and finding out. You *will* have failures, and that’s both ok and normal. Get yourself some waste material, the cheap stuff, and see what happens.
Hello friends! It’s time for a quick chat on acrylic engraving, not to be confused with etching, which is something else entirely. For engraving, just like cutting, we’re going to need opaque acrylic. Not just opaque, but darker colors. White and blue are pretty much right out too, no go. Sorry, that’s physics for you.
Anyhow, what can you do with opaque acrylic? Much like wood, you can engrave on it, shallowly or deeply, etch on it without a masking material, and cut it, of course. Unlike wood though, engraving in acrylic doesn’t give you the deep black or dark brown finish, but instead, the same color as your acrylic or a whitish version of it. Think of it like the effect of frosted glass.
Settings
What speed/power should you use? If you’re a regular in the Official D1 Group on Facebook, you should know the answer to this already – run a power speed test and pick the combination that matches what you want to do, what your project needs. Run a cut pass test to determine the combination that cleanly cuts through your material the fastest. Both types are available in the group’s Files section, uploaded by me. By reading the associated post for each test file, you will see a video on how to use the test in the first comment.
At the basic level, the faster the speed, the less depth you will get. The inverse is true for power, more power is more depth. This should give you an idea of what to expect to see in your test results.
Paper or No Paper
Acrylic sheet usually comes with a protective covering on both sides, typically made of paper, but sometimes plastic. Some people leave it on, and pick out the remaining pieces from their project later. Everything the laser touches should get vaporized, making this a viable option, but I’ve found picking afterwards to be tedious and sometimes melted bits don’t want to come out of the small details. For that reason, I habitually remove the paper unless only cutting.
Air Assist or No Air Assist
Like the paper/no paper question, use of air assist is often a question of personal taste or project requirement. When working with wood, air assist is ideally set to a low output as a way to keep smoke and particulates from collecting on/in cone type assist nozzles, as well as from the laser’s lens. Higher air volume or pressure during engraving causes a fading effect on the engraving, a less appealing result more often than not.
Acrylic reacts differently to air assist when it comes to cutting. Instead of faster/more efficient cuts, you get slower ones. This isn’t all bad though. In close examination of cut acrylic, the cuts with air assist tend to be cleaner and there is less warping or bubbling of the surrounding area. When carving, air assist tends to result in having an extra whitish appearance. Without air assist, the color is closer to the original, but material warp/bubbling may be evident.
Photos
Can you do photos on opaque acrylic? Yes, of course you can. You just don’t need to use a masking material such as tempera paint. The light touch of the laser turning the surface whitish is excellent for photos. In some ways, opaque acrylic is easier to work with that wood, as its properties are very consistent and the surface is ultra smooth. This eliminates a lot of the frustrations of working with organic materials. No more, “I had it dialed in perfectly on my practice sheet but it looks like garbage on my real one!” With a bit of fiddling, one can even get a really good greyscale upper/lower boundaries for beautiful lifelike photos minus the dither processing algorithms telltales.
Mixed Media
Just because we’re talking about engraving on acrylic, that doesn’t mean that you’re stuck with the natural appearance that acrylic has to offer. Quite the contrary. It’s suitable for multi layer paint works, like used with ceramic tiles and canvas. Laser foil is a particularly good pairing, the smooth surface of acrylic being ideal for adhesion. Because acrylic can be carved out like wood and gets a tad gooey when touched by the laser beam, powder coating media works well, as does mica. For all of the combinations mentioned above, the same techniques used for wood apply to acrylic, only the power and speed changing.
Wrap Up
Clearly, there is a lot you can do with acrylic beyond just cutting out shapes for earrings. It’s not particularly difficult to work with, and in some ways is easier to manage than wood. The key to success with acrylic engraving is right up there at the top, in the Settings section. One little test will provide you with a wealth of information which you can then leverage for any number of projects. Straight acrylic, acrylic plus one or more other media, surface colors, depths, you name it. Don’t limit your creativity or your product lines. Explore, experiment, and develop both yourself and your business.