Laser engraving el or backlit panels

[Dean Belk]

Anyone have any advice on engraving backlit panels (el panels)-----

dean

[Dan Hintz]

Well, this isn't a topic I ever expected to see here...

I've never tried it, so I can't offer general settings. But... there are a few things you should keep in mind:
1) Make sure any area you cut does not completely remove it from the layer as a whole... if it loses electrical connection with the connector along the side, it will not light up. Work the design as if it was a tube of neon, where the entire design is one tube, wrapped back and forth.
2) Unless the design is ultra-simple, expect some reduction in brightness any area that is convex opposite the electrodes (multiple electrodes will help mitigate this).

[matthew knott]

We do quite a few different backlit displays and buttons, it's normally a clear or white plastic that is sprayed black, the laser simply removes the thin layer of paint, normally I would say the wavelength of co2 is incorrect as it will mark the plastic, a yag or fibre is what's commonly used.

[Mason Atom]

Anyone have any advice on engraving backlit panels (el panels)-----

dean

I do a lot of backlit control panels for my guitar amps.

Typically I use IPI or Rowmark reverse engrave plastics and engrave the logo or text as a mirror image in the backside of the plastic.

it is really important to place a diffuser over the engraved area to make sure that you eliminate hot spots from your lighting source. The image linked above doesn't have the diffuser in place yet.

Here's a light box done in a similar manner. This was done with a mirrored red reverse engrave acrylic (1/8") from inventables.com.

Mason

[Dan Hintz]

Okay, I'm confused... are you trying to engrave the cover panel, or the EL panel itself? My advice was if you were trying to engrave the EL panel itself, but now I'm not sure if that is what you were asking... your question can be read both ways, I suppose...

[Dean Belk]

This is the type panels that go in aircraft. Most of them are powered with an ac inverter lighting a single bulb that refracts light thru i would guess some sort of embedded channel under the letters or numbers or maybe the whole panel is lit.----just wondering if anyone knows how they are stripped and recoated with what process----no telling how they were engraved or etched 40 years ago---i am sure now a days they use lasers. I am sure this might be a question for someone that has worked with and repaired el panels on aircraft. Everything has to be embedded or very flat----in other words no bulbs behind panels

[Mike Null]

Dean

I had a customer send panels like that to me wanting to refurbish them. I determined that I could not do the job with my equipment but it's been some time and I don't remember the details.

[Dan Hintz]

Ahhhhh, by "EL" you mean "edge-lit", not electro-luminescent. It all makes more sense. Back in the days they were engraved using a rotary engraver, like a mini CNC. These days, yeah, laser it the way to go.

Two ways to do it:
1) Paint a piece of clear acrylic black on the backside, engrave the painted side, light from underneath. This has the advantage of looking very shiny, but it usually requires multiple lights. Some may spray a light coat of white (or other color) over the painted side after it has been engraved to avoid seeing hotspots as easily.
2) Paint / engrave on the top side, but include a coat of clear to prevent the paint from being scraped as easily. Light through the edges.

[Mike Null]

The panels I mentioned were from a vintage aircraft and did not appear to be mechanically engraved and could not be laser engraved. Using new material such as acrylic would permit engraving but in no way would match up to the original. I wish my memory was clearer but it seems like every gauge, dial and switch had it's own lens to which a light was attached. These were from a WW2 fighter plane.

[Zlatko Kursar]

I made this from 3 mm clear acrylic, painted in gray.

[Mason Atom]

Nice work Zlatko!

[Dean Belk]

Bingo----how did you do it?----did you paint gray only and engrave the gray or did you also use white to diffuse the light more?----what kind of back lighting did you use----mine needs to be flush or embedded in the acrylic. I think boeing used a "futura" font or something similar. Nice job---

[Zlatko Kursar]

I just painted in gray and then engrave. Back light is made with LED but this part was made costumer. The blue, green and white light are button also made in same way.

[Rodne Gold]

Most of the old aircraft display panels would have been screenprinted , first white , then black atop that , most likely on glass or clear acetate , most are done from the front to stop glare , I have done some helicopter panels and used the rowmark black/clear and silver/clear, reverse engraved and then paint filled (for the white) , the biggest issue for them was NO glare , so I used the frosted version of the Rowmark , they edgelit and backlit the panel , I think the edgelighting wont work very well into the panel if its big. Its quite thin stuff too... One of the other considerations was that the panel needed to be as legible in daylight as at night.

[Greg Bednar]

I made this from 3 mm clear acrylic, painted in gray.

Very nice looking!