In this Instructable, I will explain how to use the rotary attachment for the Trotec Speedy 300 to make extremely detailed etchings around beads. The pictured beads include globes, beads with numbers and words spiraled around them in continuous lines, and some with a basic silhouette monkey to man evolution picture. I have lots more ideas for images that would look cool etched onto beads (Death Star Beads!). I'm sure you've got some ideas too - put them in the comments!
I made it at TechShop.
Step 1: Materials
- spherical, cylindrical, barrel shaped, or other approximately round beads. I bought mine here.
- spray paint, wood stain, anything you think will change the color of your beads in an interesting way so long as it's laser etch-able. I bought Flat, Satin, and Gloss spray paint, and all three worked well.
- laser cutter/etcher with a rotary attachment
- bead jig (see next step)
Step 2: Bead Jig
Step 3: Etch Some Beads
Check out this video to see how the actual etching works.
There are lots of good Instructables on using the rotary attachment in the laser etcher, so I will only be including some tips specific to laser etching beads. Read below...
Measure the diameter of the bead from hole to hole (north pole to south pole). This will be the height of the image etched onto the bead. Measure the diameter of the bead at the equator, multiply it by Pi. This is the circumference of the bead and will be the width of the image etched.
2) Focusing / Distortion
Because the laser does not move up and down, the curved surface of the sphere must be treated like the flat surface of a cylinder. This creates two problems.
First, the laser cannot be optimally focused, because the distance between the laser and the bead are not constant. The best solution is raise the bead very close to the laser, closer than the optimal focal distance, splitting the difference so the laser is too close at the beads peak and too far at the beads edge. The focal range is more forgiving than you might expect and the bead should etch evenly despite it's curve.
Second, the curve of the bead will distort any image etched onto it. As the laser approaches the edge of the bead and the slope of the surface being etched onto becomes more steep, the image becomes elongated. One way to deal with this stretching is to distort the image being etched. If you look at the attached screen shot, you'll see that the image of the map has been squished down in the extreme north and south. I'm sure there is a mathematical way of counteracting the distortion, but I arrived at this image through trial and error. Another way of dealing with the stretching at the poles is to leave a gap between your image and the edge of the bead.
Step 4: Think of Things That Would Look Cool Etched Onto Beads...
Or, leave your ideas in the comments, and maybe I'll make them.
Thanks for reading!
And one more time...
I am planning on making a lot more of these, experimenting with different materials, and producing some finished jewelry. Winning a contest or two would definitely be a good start. VOTE FOR MY BEADS.
Epilog Challenge Contest
If you think these are cool but don't have access to a laser etcher, visit my Etsy store, smallworldbeads, and support my TechShop habit!
I made it at TechShop.