The Smell of Molten Projects in the Morning

Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.

Tag: Laser Cutter

Danger Zone Earrings: GITD and PSA Vinyl FTW
With the geometry set up, cutting earrings with surface coatings is just a matter of tweaking a few settings:

Danger Zone Earrings – GITD and PSA vinyl – white light

From left to right:
- Green PSA vinyl on black acrylic
- Black PSA vinyl on edge-lit acrylic
- GITD tape stuck on black acrylic
UV lights up the edge-lit samples:

Danger Zone Earrings – GITD and PSA vinyl – UV light

And UV powers up GITD tape something fierce:

Danger Zone Earrings – GITD radiation

Cutting the central pattern out of the GITD earring might make it look even better, but I like the subtle presentation.

If it’s flash you want, then retroreflective tape is your fashion friend:

Danger Zone Earrings – retroreflective

The bolder kiss-cut lines in the middle earring might suffice, but the cutouts on the right definitely look more distinctive. Perhaps the kiss-cut perimeter line would set the pattern off a little better.

Assuming PSA vinyl sticks to itself and GITD tape well enough to survive normal handling, that would make multicolor earrings an option:

Danger Zone Earrings – multilayer PSA vinyl

On the left: blue PSA vinyl on GITD tape. On the right: green PSA vinyl on red PSA vinyl on black acrylic. Peeling the PSA vinyl is tedious and I’m still not good enough to avoid small nicks in the underlying layer.

GITD FTW:

Danger Zone Earrings – multilayer vinyl GITD

Now, to work on more patterns …
2023-06-08
Seedling Starter Pot Bottoms

One of Mary’s gardening compadres teaches a kid’s class which involves starting seedlings in “pots” made from the cardboard tubes found in paper towels and toilet paper. Cutting four slits in the bottom of the tube and folding the flaps inward puts a bottom on the pot, but what’s the fun in that?

Draw a 42 mm circle, set the layer to cut corrugated cardboard, turn the circle into suitable arrays, flatten some boxes from the heap, and Fire the Laser:

Seedling starter pot bottoms

Collect the fallen disks from the chip tray and jam one in place as a serving suggestion, where it fits like it was custom-made:

TP roll seedling starter pot bottom

You’d still want to fold some flaps over the disk to keep it in place, but now your pot has a real bottom.

I have no idea if 42 mm is a Galactic Constant, but it worked for the pile of tubes we had on hand.

That was easy …

2023-06-07
Danger Zone Earrings: MVP

Some geometry review and a bit of fiddling with LightBurn produced regularized patterns suitable for laser cuttery:

Danger Zone Earrings – radioactive – handful

A key trick: circumscribe the figure with a circle on a tool layer, then group the whole mess together, so that the center of the circle coincides with the desired center of the figure. In particular, the geometric center of an equilateral triangle is not at the center of its vertical extent:

Danger Zone Earrings – radioactive – LB layout

The dark blue layer engraves the surface, the red layer cuts through 3 mm acrylic, and the light blue layer is the tooling.

I like the edge-lit ones, although the simplicity of laser-cut clear acrylic is hard to beat:

Danger Zone Earrings – radioactive – white light

Wearing them in a place flooded with UV radiation would set you apart:

Danger Zone Earrings – radioactive – GITD UV

The careful observer will note stress cracking in the two clear earrings in the middle row. Those came from the vintage paper-covered acrylic sheet and I used alcohol to clean off the not-quite-vaporized glue just to see if isopropyl alcohol would behave differently than denatured alcohol. Nope, the cracks appear instantly.

Peeling the paper and engraving the bare surface produced the clear-frosted earring in the upper right, with the radiation symbol cut out of the sheet. Engraving without surface protection tends to deposit vaporized acrylic dust everywhere, so it would require hand cleaning without the cutouts.

The cutouts get 0.1 mm inward offsets to slightly increase the wall thickness around that central circle.

One combination I didn’t try: engrave the triangle perimeter for emphasis and cut out the symbol for contrast with edge-lit acrylic.

Dropping other symbols into place should be straightforward, with the center of the circumcircle as the snap target.

The LightBurn SVG layout as a GitHub Gist:

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2023-06-06
SCP Warning Label Earrings: Rattlecan Feasibility Test

Our Young Engineer provided different specs for earrings than I’d been using, which prompted a quick-n-dirty test to see how they might come out:

SCP Warning Labels – test 1

The images come from the SCP Wiki with tweakage for better contrast:

SCP warning signs – BW 3×3

Then I traced them into LightBurn vectors suitable for engraving, added hanging holes, and fit a perimeter cutout. This being a test, I took a number of shortcuts resulting in slightly off-center engravings and ignored a number of image botches (most notably in the Inconsistent Topology figure.

A quick painting fixture kept (most of) the rattlecan paint off the edges:

SCP Warning Labels – fixture clamping

The acrylic is old enough to have brown paper protective layers, rather than fancy plastic sheets. I peeled various combinations and shot various sides with purple:

SCP Warning Labels – purple coat

Remove some, flip others over, and hit ’em with yellow:

SCP Warning Labels – yellow coat

I expected purple markings over a yellow background to look best:

SCP Warning Labels – purple over yellow

But the inverse version seems more contrasty (ignore the off-center cutout):

SCP Warning Labels – yellow over purple

I think the purple-on-clear version would look better with edge-lit acrylic:

SCP Warning Labels – purple over clear

The 0.15 mm line spacing seems too coarse, but trying to get a perfectly flat engraved bottom seems futile.

A second coat of paint on the engraving would definitely boost the contrast.

If you were going to do this for real, you’d definitely recreate the images with vectors right from the start, using the original images as inspiration.

All in all, I like ’em, but there’s some improvement required before anybody else does!

2023-06-05
Earring Laser Fixture

Cutting or engraving patterns on earrings should go more smoothly with a fixture:

Earring fixture – demo install

That’s a serving suggestion, using the Biohazard test pieces, which also helped align the top and bottom layers while gluing:

Earring fixture – clamping

That used all my little clamps: obviously I need more!

The bottom layer (red) is MDF for strength and the top layer (orange) is chipboard because that’s all it needs:

Earring fixture – LB layout

The little tab along the top ensures alignment using the jump ring cutout. The central hole will let me cut through the earring, should that be necessary.

The two strips over on the left get glued on the bottom, spaced to align along one of the aluminum knife blade rails, as with the craft stick fixture. With that lined up, any two of the four targets will serve to align the template with the fixture using LightBurn’s Print-and-Cut tool, as with the craft stick template.

Now, to make some smoke!

The LightBurn SVG layout as a GitHub Gist:

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2023-06-01
Biohazard Earrings

More desk clearing revealed a sketch for another trinket:

Biohazard symbol

That’s built directly from the original specs to get the spacing and symmetries correct. The freebies I could find all suffered from various degrees of bad design & layout.

A chipboard coaster provided some reassurance:

Biohazard coaster

Shrunken down to 25 mm OD, the tips become vanishingly small:

Biohazard earring – vinyl sample

It’s the same laser-safe polyurethane vinyl as the SD card reader, this time applied to 3 mm black acrylic. The “gold” ring is just parked in place, as this one wasn’t presentation-quality.

Contrary to the usual transfer-tape method of applying PSA vinyl, I stuck the sheet to the acrylic before cutting, then weeded it directly off the acrylic:

Biohazard earring – vinyl weeding

Kiss-cutting the vinyl with dot mode ate into the acrylic, but the soon-to-be-weeded areas protected the surroundings and the result came out looking pretty good. To me, anyhow.

Flushed with success, I tried some almost certainly not laser safe glow-in-the-dark tape:

Biohazard earring – GITD weeding fail

The mess in the upper left is the tape’s double-sided adhesive intended to hold the glowy layer in place forever. Of course it weeded poorly!

Seen in its natural environment, however, weeding may not be necessary:

Biohazard earring – GITD tape glow

Engraving the rebated rim leaves quite a bit of debris & scorch marks around the perimeter. A mask layer atop the GITD tape seems like a Good Idea™.

The LightBurn SVG layout as a GitHub Gist:

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2023-05-29
Engraved Popsicle Sticks

Having found a handful of popsicle sticks on my desk, I had to finish this up:

Popsicle stick markers – engraving

The fixture has the same layout as the craft stick version, sized to fit the smaller sticks. They’re a bit thicker than the chipboard sheet, but match up well enough for the purpose.

Even though the sticks don’t have much room for cutout letters, I had to try it anyway:

Popsicle stick markers – finished

Aligning the template to the fixture uses LightBurn’s Print-and-Cut tool, which seems easier than nailing the fixture to the laser platform.

I suppose if they ever make actual popsicles with wood handles, they can tell who gets which one.

For whatever it’s worth, the larger craft stick markers in the garden remain in good shape.

2023-05-26