Ed Nisley's Blog: Shop notes, electronics, firmware, machinery, 3D printing, laser cuttery, and curiosities. Contents: 100% human thinking, 0% AI slop.
Tag: Improvements
Making the world a better place, one piece at a time
Sharpereyes than mine pointed out I misspelled Poughkeepsie, so I took advantage of the opportunity to make the whole thing look better:
Library card tag – revised front
It turns out the low-surface-energy tape stuck like glue to the acrylic tag (because that’s what it’s designed for) and peeled right off the laminating film on the printed paper. So I stuck some ordinary adhesive film to the back of the new paper label, left its protective paper on the other side, cold laminated the film+paper, laser-cut the outline, peeled off the back side of the laminating film with the protective paper, and stuck the new adhesive to the LSE tape still on the tag.
I have no idea how well this will work out in the long term, what with two adhesive layers bonded to each other, but this whole thing is in the nature of an experiment.
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:
Holly Coaster – mirror flaws
So I re-did the layout to put the 3 mm mirror in 3 mm thick plywood:
Holly Coaster – overview
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:
Holly Mirror Coaster – LB layout
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:
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:
Holly Coaster – adhesive placement
Peeling off the paper reveals the adhesive tape stuck to the back side of the mirror:
Holly Coaster – adhesive exposed
Apply the similarly embiggened aluminized Mylar to the adhesive:
Holly Coaster – mylar placed
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:
Holly Coaster – edge view
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 two on the left are the original snowflakes with interchanged innards and, perforce, no kerf compensation.
The upper-left coaster has a wood flake surrounded by acrylic, which makes a sharp clack when you set a glass down on it. The wood surrounds emit a much more pleasing clunk.
The next two have 0.1 mm compensation applied to their acrylic snowflakes, which produces snug fit (original on the left, compensated on the right):
Snowflake Coasters – kerf corr 0.0 vs 0.1 mm
Applying 0.2 mm compensation makes the flakes impossible to push in, so the true compensation is somewhere just over 0.1 mm. I think you could optimize for a specific wood and acrylic combination, but, as with 3D printing, any change requires something different.
The little arrowhead shapes tend to get lost, so collecting them on a strip of tape while you’re hunting in the chip tray helps:
Snowflake Coasters – plywood cutouts
The dark flake on the right got a coat of walnut stain, as did the two darker coasters in the first picture. It looks better in person than in the photo, although Mary still thinks the lighter wood sets off the white acrylic just fine.
The two large (120 mm OD) coasters fit my 20 ounce mugs, with the Nanook Memorial Coaster in the lower right.
The rather battered library card on the bottom has been rattling around on Mary’s keyring since late in the last millennium:
Library card tags – front
I made the one on the top as a replacement, because Mary wanted one, but the library no longer issues keyring cards these days.
The front surface was laid out in The GIMP, inkjet-printed on good paper, cold laminated, laser-cut with LightBurn’s Print-and-Cut process, then affixed to the acrylic tag with really good double-sided tape:
Adriance Card – LightBurn PnC layout
I cut and applied the tape after cutting the tag, but the next time around I’ll apply the tape to the stock and cut both together to improve the edge alignment.
The smaller text uses dot mode and the bars & number are engraved:
Library card tag – detail
In retrospect, it’s painfully obvious the engraving passes should run parallel to the bars, rather than perpendicular to them.
The barcode uses Codabar encoding generated with a Codabar font. I scaled the graphic block slightly larger than the original in the hope of making it more readable.
I determined the start and stop characters by trial and error; for this card, they’re A and B. Which could, perhaps, stand for Arlington Branch, but might equally well be coincidence.
It worked perfectly on the first scan at the library counter and apparently went entirely unnoticed. I trust duplicating a library card does not constitute a federal offense.
For what should be obvious reasons, however, I’m not posting the LightBurn layout.
Despite cogent reasons for not buying another Sears vacuum cleaner, the brand currently represents a local maximum of the desirability curve: cheap, readily available, works well enough, and, surprisingly, bags for the defunct Progressive (whatever that meant) vacuum seem to fit just fine.
But the new one does come with some annoyances, starting with trendy dark gray engraved / molded control markings:
Sears Vacuum – power and cord controls
Quick: from the other end of the vacuum hose, which one must you stomp to turn it off?
It also has a simple rotating suction control ring at the handle:
Sears Vacuum – marked suction vent control
Which, as you can tell from the fluorescent tape, featured the same embossed and unreadably small dark gray markings.
Because that ring and its glaring tape is invisible from the user’s end of the handle, I eventually duct-taped the ring in position to prevent another inadvertent loss-of-suction accident.
If we ever need reduced suction on a regular basis, I’ll conjure a better ring from the vasty digital deep:
Sears Vacuum – suction vent doodle
I obviously no longer form deep emotional attachments to these things …
The rattlecan chipboard coasters having passed their Best Used By dates, I figured a more durable seasonal version was in order:
Snowflake Coasters – overview
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:
Snowflake Coaster – LB layout
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:
Snowflake Coasters – detail
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
Mary made a neck cozy based on a Craftsy description using a pattern I’d extracted from the low-res photo and rescaled to the proper size. The perimeter came out grittier than I like, but the laser had no trouble chopping it from a sheet of paper, and she cut smoothly around the lumps:
Neck Cozy mask – right
It looks better on her, but you get the general idea:
Neck Cozy – rev 1 finished
After some experience, however, she wanted to lengthen the top and bottom seams to improve the way it draped, which meant I had to modify the extracted pattern. The original pattern in the Craftsy photo was hand-drawn (which is perfectly fine) and the two halves were of two different sizes; we decided to work with the left half and produce a symmetric result.
Rather than fiddle with the bitmap, I drew a rectangle around the outside of the left pattern mask, converted it to a path, moved the nodes to key locations, then fiddled with the control points to lay the splines along the perimeter:
Neck Cozy pattern – LB splines
Removing the bitmap makes the splines much more obvious and shows the much smoother perimeter:
Neck Cozy pattern – LB extended splines
Adding a few nodes to change the splined shape is much simpler than fiddling with the bitmap, particularly when tweaking their position as directed by someone who knows how the fabric will eventually take shape.
Add fiducial marks and a label, duplicate the shape, mirror it to get the other half, and fire the laser:
Neck Cozy pattern – as cut right
Fabric cutting isn’t in my wheelhouse, but I made the offer …
The Smell of Molten Projects in the Morning 
