Tips for engraving for edge lighting acrylic?

[Keith Upton]

The recent large glass mural thread has me wanting to experiment with doing some edge lighting. Since I have 1/8 acrylic on hand, does anyone have any tips that will make for better engravings for this? Should I be using cast or extruded, should I engrave deeper then normal, etc?

Thanks again for all the help you guys and gals freely give out on this site!

[Scott Shepherd]

Cast and not deep.

[Matt McCoy]

Have you tried this material?

https://www.inventables.com/technolo...-acrylic-sheet

[Keith Upton]

Nope, but that looks cool! Thanks for the link.

[Keith Upton]

Cast and not deep.

An answer in 4 mins... got to love the internet and this site.

[Mitchell Tutty]

Absolutely cast, I also have a 60w epilog and i'm running settings of 100s/50p with 300dpi or if i have artwork needing 600dpi engraving i'm using 100s/30p, these give in my opinion the best depth for edge lighting acrylic. These setting should give you a starting point, but will most likely need tweaking for your machine.

[Keith Upton]

Thanks Mitchell, I've got a 60w epilog as well, so your settings should get me really close. Have you found that thicker acrylic gives better results?

[Joe Pelonio]

If you do some experimentation, you will see that line art done with vector cutting (shallow) rather than engraving gives spectacular results. I agree on using cast acrylic. The best effect is on green edge clear.

[Glen Monaghan]

Edge lighting works by shining light into the edge of the acrylic, and the light pretty much just passes straight through toward the opposite edge until it hits a "scatter point" such as a hole, scratch, or engraved area. So, a thick plate gives the light a larger cross section to pass through, while a thinner plate confines the light to a smaller cross section (so it can't spread out so much). Assuming that the light is fairly uniformly spread across the thickness (not really true, especially close to the lit edge, but still a working approximation), a 1 mm deep engraving into the thick plate will intercept and scatter less light and appear dimmer than the same 1 mm deep engraving into the thinner plate. I suspect the ideal thickness is whatever matches the size of the light source.

[Keith Upton]

I've seen people talk about vector engraving, but I've never done it. How would I go about doing that? Assign a color to vector cut, but on low power? I'm attaching some artwork I'd like to use for these test.


Camel.jpg

That's just a low res jpg of the file. I have it as a vector as well.

[Keith Upton]

Edge lighting works by shining light into the edge of the acrylic, and the light pretty much just passes straight through toward the opposite edge until it hits a "scatter point" such as a hole, scratch, or engraved area. So, a thick plate gives the light a larger cross section to pass through, while a thinner plate confines the light to a smaller cross section (so it can't spread out so much). Assuming that the light is fairly uniformly spread across the thickness (not really true, especially close to the lit edge, but still a working approximation), a 1 mm deep engraving into the thick plate will intercept and scatter less light and appear dimmer than the same 1 mm deep engraving into the thinner plate. I suspect the ideal thickness is whatever matches the size of the light source.

That makes sense thinking about it.

[Jon Sollee]

Keith,

The image engraved does not have to be deep at all. The light will naturally light the image and give it a glow. The thicker the material the better. It also depends on how close the LEDs are and how powerful they are.

[Keith Upton]

Keith,

The image engraved does not have to be deep at all. The light will naturally light the image and give it a glow. The thicker the material the better. It also depends on how close the LEDs are and how powerful they are.

Thanks Jon. Your glass project in the other thread was what had me thinking about the thickness. Thicker material of course gives it a nicer look and heft, but I was wondering if it also played a part in the look of the lit engraving.

[Jon Sollee]

The LEDs used, and how close to the edge of the material, played a huge part. It was 3/8ths thickness Starphire glass, which has no green in it. The thickness did help get the lighting all the way through. Also, the fact that we lit all four sides helped with getting the "dead" spots lit in the glass.

[Keith Upton]

Besides precieved quality/value, is there any big difference between acrylic and glass when it comes to how the etching looks? As I mentioned in the other thread, I'm wanting to do some of these to decorate my garage after the makeover. Obviously acrylic would be safer in that environment, but if glass would give a superior result...

My current thoughts are to have this surrounded by cabinets, so I don't think lighting it from all four sides should be an issue. But since my laser is only 12x24, the end product will not be that large anyway... perhaps it would only need to be lit from top and bottom.