[RPPerry3]

I'm using 1/8" Extruded Acrylic Opaque White Sheets, painting them Gray, then engraving into the gray to expose the white for backlit aviation panels in my flight sim. I keep getting poor results and hoping to get some help from those more experienced.

Machine: I have a self-built Joe's 4x4 Leadscrew driven cnc with 420oz steppers. (Dual Y Axis Motors and leadscrews) 48"x40" work envelope
Spindle: Makita Variable speed palm router 10k-30k RPM
Engraver: 60 degree V-bit 1/8" tungsten carbide for plastics
Piercing Cutout Bit: Freud O-Flute 1/4" for plastics (Acrylic and Poly-carbonate)

I think I get the best results so far with air blower to remove chips and very shallow passes (0.01" per pass)

ENGRAVING: The engraved letters are very visible with back lighting present, but I can barely see the letters if not backlit. This is only for areas that have been milled/routed. The back of the stock is still brilliant white. Looks as maybe the routing process dulls the vibrancy of the white?

PIERCING CUTS: Hit or miss regardless of feed rate. I'm cutting mostly at 0.01" passes and 70IPM.


Here are my pitiful face plates and engravings thus far.
Attachment 410932
Attachment 410934

[the_gentlegiant]

You will have a lot better results using sign plastic. This stuff comes in millions of colors too. What it is is a clear sheet with a layer of color. You engrave off the color and you can either shine light through it or use acrylic artist paints to fill it in and make multi colored stuff. I think you can even use transparent paints and or lighting gels if you're bound and determined to use back lighting.

The engraving layer is only around 0.005 thick so no trouble. I've done it both with engraving cutters and small end mills. Works great.

The best part is you can do it in reverse on the back, so your front panel is smooth and won't collect dust over the years. The stuff can be cut and machined to shape like any other sheet plastic.

Check out Johnson Plastics website. The hardest part will be choosing.

Also a rule of thumb is your letter width should be around 12% of the letter height.

Here's what I mean about using paint. A plate for a pallet changer. Any color combo you like.

[RPPerry3]

Thanks for the recommendation Giant.

[UncleBobsWorkshop]

Cast acrylic cuts much smoother.