Cutting Sheet Plastic

[swamper8]

Good evening everyone,
First post here. I've scanned the forum titles and I'm not sure the best one to post my question in. So I will try it here, if someone thinks it's more appropriate for another forum please let me know.

I've taken a picture of the part I am trying to duplicate. The piece in the picture is a 'overlay' for a gauge pod in my car. No one makes these, and this one is tinted orangish/red, so it's impossible to change dash light colors. Though all the hashes/numbers etc appear whitish in the picture, when held up to the light there's actually a tint to it. This piece appears to be made of multiple layers, though it's perfectly smooth on top.

So my thought was is there a CNC device, be it laser, something that physically cuts, router/dremel etc etc which could be capable of taking a thin sheet of plastic and making letters/numbers/symbols/lines? Though I don't know how this exact part could be duplicated, I thought if i could etch/cut the letters/numbers/lines in a thin sheet of plastic, I could overlay that on a opague sheet (to act as a light diffuser to the bulbs behind it) and then start making these custom pieces.

I am a electronic engineering tech by trade, I can solder through hole/surface mount quite well and am very mechanically inclined. i'm willing to spend up to $1000 dollars, and would be happy with either a fully assembled machine, or, most likely, a kit that I could put together myself. it wouldn't have to be big, just a 'table top' unit, maybe with a 1'x2' or 2'x 2' bed at the most.

I really don't know what device I am looking for and would appreciate some advice on this. I think I need something more robust than a vinyl cutter, but I can't afford $3000-5000 for most of the CNC machines I find on the internet when I do a google search.
Thank you!

[zax15uk]

Hi Swamper8, welcome to the forums.

I've seen people making these (custom gauge overlays), so if you just want them for personal use the best solution would be to buy from someone with the equipment that already does it. If you're looking to sell them, read on.

The material in your picture appears to be an ABS, or thermoplastic. These can be etched and cut with a laser but since the material melts rather than vapourizes it is difficult to get 'clean' results. You could also use a CNC router and reverse engrave, then fill with clear resin.

It may be easier to create a sandwich using 2 or 3 thin layers, a laser would be a good choice. It could do the fine engraving of the top layer and cut the transparent layer and then the final back (if needed).

Your budget will limit options, but it is possible to build a small CNC router for that and you can also buy a used or Chinese small desktop laser for about that - so I think you can make it work.

Another option that may work is 3D printing, I don't have any experience with this technique but it would be worth looking into. Not sure about the cost.

Zax.

[swamper8]

Great, thank you for your response. I was actually thinking of making it a small business. Though I'm sure there are people who are making these, I just have never seen any mass marketed, easily available pieces for my car. And most likely because all the lighting in the car is surface mount LED's, not bulbs, so they can only be changed by someone who has the skill and motiviation. (the overlay is tinted AND the LED's are colored, it's not like they just use white LED's and only tint the overlay) So I'm hoping I may have small nitch market. I guess I can spend a little more as I usually like to buy quality. I've never seen pictures or info on anyone who's successfully changed the colors of their interior lighting for my car, so I may very well make my money back in short time. (being an optimist anyway)

I think your idea of sandwiching 2-3 layers is ideal. And you say a laser machine can do the top layer as long as I choose the right plastic (I.E. something that won't melt)
If you could suggest some makes/models/websites of these devices I would appreciate it. Just something to get me started and I should be able to do the leg work from there. It seems then I might be in the right forum for this

[zax15uk]

You can actually cut thermoplastics, and if they are thin enough the results can be acceptable. ABS or similar may be an option. Acrylic would be an excellent alternative though as it cuts much better.

I'm not sure, but Rowmark or similar multi-ply laser engravable plastics may work. I would probably look at the reverse engravable or frosted Acrylics, with the reverse engraved you would have a nice smooth front surface for the gauges and could etch through to clear.

This could be accomplished with any CO2 laser, so your options given the budget would be a used system or a low cost desktop Chinese machine.

It would also be possible to reverse engrave this type of material using a small CNC router.

You might want to check with some local signmakers too, there are some options with vinyl printing that would be suitable too. There is a tool called the Gerber Edge that deposits (actually it heat bonds) layers of very thin pigmented films onto a thicker vinyl substrate. If that substrate were clear you could produce the same effect. They also make a self leveling clear epoxy that can be used to cover vinyl and results in a hard plastic.

Zax.

[swamper8]

Can someone give a explaination of what 'reverse engraving' is? It seems like I'll have to try some sort of build-your-own CNC router or, like stated, maybe find a cheap or used laser unit.

[zax15uk]

Reverse engraving is just engraving in 'reverse' from the back.

You mirror the design before sending it to the laser or router, and put the material face down and cut the back side. it has the benefit that the front surface remains smooth.

Zax.