Any makerspace with a laser cutter should have on hand a nice set of simple, small designs to use on scraps. This is handy for two reasons:

You can make use of the odd shapes left over from big projects
It's a great way to teach new people how to use the laser cutters (and produce something usable, instead of a chunk of plastic that says "test")

This guide will show you how to cut handy keychains from garbage in several different ways!

We make keychains from

discarded CDs,
failed 3D prints
homebrew recycled plastics,
and laser cutter scraps!

Inspiration
We work with an animal rescue that keeps getting more and more animals to rehabilitate, and they needed ways to label their keys (because they have dozens of different animals in different housing facilities). Most of the animals are here because humans have destroyed or fragmented their habitats in order to extra resources from the earth. So we wanted to find a way that wouldn't contribute to habitat loss and could actually help take some pollution out of their environments. By the way if you want to donate to an amazing animal rescue (or just look at all their super cute sloth videos) check out the instagram of the APPC here in Panama!

https://www.instagram.com/appcpanama/

Supplies

CDs / DVDs
Garbage Plastic (#2 HDPE, #5 PP, disposable masks (also PP), or 3D printer Filament (often PLA)
Laser cutter scraps

Step 1: Get Designs

You can use any of the animal silhouettes we made. Download them here:

https://github.com/Digital-Naturalism-Laboratories/Dinalab-Keychains

If you make more cool animal silhouettes, you can feel free to add to this repo! it's nice to have more fun animal designs for people to freely use! The current animals we have in there are all based off our rescue animals in Panama!

Create Your Own

Or you can create your own! For the key chain holes, we experimented with different sizes and a hole 5.5mm wide, with an outer circle 11mm in diameter seemed to work well to fit many key chains and keep the hole strong.

Step 2: Cut From Old CDs

CDs and DVDs are made from Polycarbonate. It's not a material known to cut well with most laser cutters, but you can do it! It just tends to be smokier and harder to cut than nice things like acrylic. Just use many passes at high speeds, and you can get through those CDs. (We would do 8 passes).

Also CDs cut MUCH easier rainbow-side UP towards the laser, BUT they tend to look a lot worse. We cut ours rainbow side down. Much of the nasty burn looks end up on the side of the CD you would normally write on.

These CD keychains are definitley the coolest looking, they tend to be more brittle and thin though. So in your designs you might want a thicker ring around the keyhole. They would be really good for rainbow mobiles too!

Step 3: Shred, Melt, and Cut Your Own Plastic

For a full explanation of how to melt down certain thermoplastics into sheets you can laser cut, check out my other how-To article explaining how to melt down littered disposable masks into ear-savers for wearing more masks!

https://www.instructables.com/Ear-Savers-From-Garbage-Masks/

In short, you can

collect #2 (HDPE) #5 (PP) plastics or several 3D printer plastics (recycled your failed prints!) like PLA
shred them up by hand (use shears or scissors or a hammer for brittle plastics)
shred them with an industrial grinder (if you are in panama hit me up!)
get a cookie tray, put on some parchment paper, sprinkle on the plastic shred, lay parchment paper on top, put on another cookie tray, put weights on top, put in oven or hot plate at 200C for 10 minutes.
Let cool
Laser cut the sheet of material!

I got a lot of our plastic from raiding a site where people (and a hotel) has just been dumping their waste. Lots of milk jugs = HDPE heaven!

Step 4: Cutting Recycled Plastic Pointers

#2 HDPE and especially #5 PP don't cut particularly well in many laser cutters. They tend to melt a lot around the cut, and that melty stuff fills back in the areas you were trying to cut. So again you could try to do lots of fast passes, or make sure to have a really good aircompresser that can keep those lines open. Also make sure not to make your sheets much thicker than 2mm or they are hard to cut through!

PLA (from upcycled failed 3D prints) actually cuts fairly decently, don't make these sheets too thin though, because they are brittle!

Step 5: Cut From Acrylic or Plywood Scraps

This is the easiest thing, and you just need your scraps from other projects! To make multi-color details, I find scraps that still have their protective cover on the acrylic (or you can add masking tape if there is none). Etch and cut the

So just find scraps left over, load up your designs, and slice out some keychains!