What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Engraving switch plates

leok

Well Known Member
I?m not sure where this post belongs as it has electrical, interior, Tips and Techniques or tools. I think it fits best in Building tips and Techniques.
What started as a simple desire to have backlite switch labels (like every car has) in my project slowly morphed into a rather significant sub-project. I decided to mount my switches, grouped by function and location on 1/8? engraving plastic. I decided to use black under clear. This allows what is called 2nd Surface (meaning backside of the plastic) engraving with back lighting. The lettering is seen from the front, but actually engraved into the underside.

20180102_214225.jpg
[/url][/IMG]

By engraving on the back, cutting away the thin black layer of plastic, the back-lighting shows through the clear plastic with a smooth tactile surface on the front. When the lighting is off the engraving shows up as white. Using a smoke colored plastic instead of a clear will make the lettering disappear when the back-lighting is off.

20171210_195246.jpg
[/url][/IMG]

I first had my son, who has a laser engraver cut samples. Too much plastic residue from the laser muddied the edges of the engraving to get sharp graphics. The next plan was for my son to use his small X-Carve CNC router to engrave the switch plates. Since those machines are part of his business and in constant use, one thing led to another and I ended up getting an X-Carve for my own shop (since I never met a tool I didn?t want).

20171207_162221.jpg
[/url][/IMG]

What I didn?t appreciate until I started cutting, was how much development would be required to engrave 14 pt font details into the plastic. After way too many trials and cutters to talk about here I ended up with a 0.5mm spiral flute engraving bit. As you can imagine, I had a lot of breakage. Some 20 bits in all. One, I swear, I just thought about it and it broke.

20180109_211935.jpg
[/url][/IMG]
 
I once had a CNC Water Jet and was very good with 2D Autocad and the software to cut code. Unfortunatly with many computers since then, the software I used is long gone. This time, I used Power Point to lay out the text and graphics. That was saved as PDF and imported into Illustrator. (Only because I am not good enough at Illustrator to do the layout there.) Illustrator command for Outline was used to create line tracings of the font/graphics and then exported to SVG format. SVG was imported into Easel (X-Carve online software) to cut the G Code and drive the machine interface.

20180111_201417.jpg
[/url][/IMG]

A few photos of the finished and installed switch groups with the back lighting on.

20180115_134856.jpg
[/url][/IMG]

Overhead panels

20180113_171252.jpg
[/url][/IMG]

Instrument Panel

20180117_211658.jpg
[/url][/IMG]

Overheat light panel

20180117_211713.jpg
[/url][/IMG]

A few lessons learned

Run slow to avoid braking such fine bits. 7 IPM worked well most of the time for the engraving portion of the cut
Run low RPM to avoid melted plastic sticking to the cutter and destroying the graphics. 2500 RPM seemed to work most consistently
Cut less than 0.015 inches deep per cut to avoid both of the above issues.
Run a zero depth pass to account for imperfect flatness. (The plastic surface varies in height without a vacuum table)
The software wouldn?t cut the font I chose with a programed bit any larger than 0.01 inches due to overlap of offsets. So programing a 0.01 bit and using a 0.5 mm (0.02 inches) actual bit gave a slightly bolder font.
 
It turned out really nice!

Just to pass a long some tips to your son, I have a 45w CO2 laser engraver/cutter. I have done this sort of panel and backlighting with good success on my laser. It does require an "odd" setup from most of my normal jobs: I use a 1.5" focal length lens, and I use an extra sheet of masking paper on the plastics to keep the smoke/fumes from staining. You'll need to run A LOT of air assist to help cool the plastic as the laser ablates it away, thats crucial to getting very nice smooth lines when cutting / engraving super fine fonts.

Since the 1.5" lens has a very short focal length, getting the focus is absolutely crucial, I even account for the few thousandths that I ablate away when I am engraving.

I also use a very high power, and a very high speed when engraving plastics and acrylics to do similar to what you've done. The high power and high speed doesnt give the plastics a chance to melt and distort. If you're son is using his laser for production work, he's likely got a laser that has good gantry's so high speed accuracy should be fine.

Hope that helps! The laser cutting/engraving/etching business is very closed off. Its very hard to find folks that are willing to share tips, so I try to share anytime I learn something new and useful.
 
Thanks

Lynn, thanks for the feedback, I'll pass it on.

I'm not sure of the details on his Laser. He uses it in his woodworking business for both cutting thinner stock as well as engraving. This was his first try at plastics. It is an amazing machine.
 
This is really cool. Will you make this available to the RV community?

I'm not looking to go into business, but will always help a fellow aviator out. I say that mostly because I have limited time to work on my own project until I retire in a few years.
The process is identical to the nameplate etc. engraving used for office nameplates. Depending on how fine the text is, it should be fairly easy to find sources locally. It also sounds like the Laser method is viable if you can find someone who knows the correct setup.

I posted for two reasons. 1. To show the concept of switch backlighting and second surface "printing" of text. Having the text on the back side makes the plates easy to keep clean, and very permanent as well .
2. To show a new toy with many uses. The CNC can be used to cut any number of things including aluminum. Part of the builders journey for me is exploring new skills and methods (to me).

As a final note, I also made lots of adjustments that would have cost me several iterations if outsourced. :D It was nice to be able to just make the new plates rather than judging if it was worth the cost in time and money to send a new iteration out for engraving.
 
What do you use for the backlighting

DEM,

I used 12V LED light strips. They are readily available at low $s from ebay. In my case I went a little crazy and used RGBW light strips and set them up so I could control each color intensity independently with pots. That added some extra time in the wiring. You can see the results here in my build log http://www.mykitlog.com/users/displ...project=2446&category=12453&log=231016&row=27

Because the back if the IP is open you have to make a back shroud to close in the light if you don't want leakage. I made small ones around each switch group closed at the ends with a piece of black foam.
The other item to be aware of is the shadows cast by the switch bodies themselves. Placement of the LED strips to light evenly took multiple short strips in most cases. I still didn't get it perfect in every instance as can be seen in the pictures.
 
Back
Top