Tag: Improvements

Other than demonstrating that it’s possible to laser-engrave a 3 mm deep pocket in a ¼ inch thick piece of scrap paneling, the process didn’t have much to recommend it:

So I re-did the layout to put the 3 mm mirror in 3 mm thick plywood:

The coaster has a self-adhesive cork pad on the bottom, which required an intermediate adhesive layer holding the aluminized Mylar reflector on the bottom of the mirror to brighten the colored areas.

The LightBurn layout shows all the pieces:

The plywood cuts with the good side down, although “good” is certainly a judgement call with B/BB grade plywood. I cover the good side with blue painter’s tape to reduce scorch marks. In a real application, you’d do some sanding and finishing, probably before cutting; in this case, I want to see what happens to bare wood in coaster duty.

Engrave and cut the mirror with the backing upward:

The tracer rounds may be burning aluminum.

I colored the engraved areas with fat-tip permanent markers, despite knowing the alcohol will crack the acrylic. In real life, you’d use spray paint, probably with laser-cut tape masks.

The adhesive layer extends 2 mm beyond the mirror perimeter to stick onto the bottom face of the plywood:

Peeling off the paper reveals the adhesive tape stuck to the back side of the mirror:

Apply the similarly embiggened aluminized Mylar to the adhesive:

Cutting the holly shape directly from the original foot-square adhesive sheet lets me tuck smaller shapes into the remaining uncut areas. In a production environment, however, joining the Mylar and adhesive (perhaps using pre-cut squares), then cutting them as one sheet would definitely simplify the process.

Then peel-n-stick a cork disk (thus explaining why the plywood is exactly 4 inch OD) on the bottom:

I’ve been aligning the cork by feel, which explains the half-millimeter overhang along the right side. Inexplicably, I have yet to justify an alignment fixture.

The LightBurn SVG layout as a GitHub Gist:

The rattlecan chipboard coasters having passed their Best Used By dates, I figured a more durable seasonal version was in order:

I laid out the design with the intent of cutting an acrylic snowflake with a bit of compensation to fit snugly into a plywood background:

At the last moment I realized I could just cut two of the patterns on the left, swap the snowflakes, and get two coasters with very little scrap:

Mary thinks the gap between the snowflake and the background looks OK. I’m not convinced, but studying the results suggests applying enough kerf compensation to close the largest gaps would results in the rest of the flake not fitting into its socket. Plus, of course, you’d have more scrap.

Embiggening the small dagger-shaped pieces around the center would be an improvement. Perhaps cutting those as a separate operation after arranging them in a corner would work.

Protip: Align the grain in those daggers with the rest of the plywood, because It Will Be Very Obvious if you don’t.

Applying a nice wood stain / finish to the plywood, perhaps before cutting it out, would certainly improve the result.

Invisible on the bottom: self-adhesive cork disks eliminating the need to glue the pieces to something else. I had thought of a blank plywood or MDF disk, but came to my senses just in time.

The original SVG fell with a blizzard from one of the many SVG snowflake generators out there. Because LightBurn uses only the stroke centerlines of SVG images and ignores the stroke width, it required some tweakage before becoming a coaster.

After saving an SVG flake from the blizzard, fire up Inkscape:

• Import the SVG file
• Center it in whatever page you’re using
• Ungroup the flake from the frame (if it has one)
• Delete the frame to leave only the flake
• Select the flake
• Invoke Path → Stroke to Path
• Save as an SVG image under a new file name

Then fire up LightBurn:

• Import the tweaked SVG file
• Assign a layer with line (rather than fill) parameters
• Ungroup to separate the flake’s strokes
• Weld the strokes together to remove the overlaps
• Wrap a coaster outline around it
• Resize the flake as needed
• Set layer parameters as needed
• Duplicate the flake
• Embiggen as needed
• Unleash the laser!

The LightBurn SVG layout as a GitHub Gist: