Laser-cut Punched Cards

I just had to do this:

Laser-cut punched card samples
Laser-cut punched card samples

It took several iterations to convince me I can’t quite pull it off yet, but the idea shows promise; the GitHub repo includes useful links to other variations and techniques.

The top card starts with hole locations / column numbers preprinted by the inkjet, then (nearly but not exactly) aligned in the laser cutter for “engraving” the variable text and “punching” the corresponding holes. The other cards represent various steps along the way, all of which demonstrate why a 60 W laser is the wrong way to print text on cardstock:

Laser cutter - engraved punched card
Laser cutter – engraved punched card

Aligning a preprinted sheet in the laser cutter with sufficient accuracy to hit all the holes turns out to be a significant challenge: the red dot laser pointer hangs off the rear of the nozzle with the beam at a steep angle:

Magnetic Honeycomb Spikes - MDF
Magnetic Honeycomb Spikes – MDF

Which means the red dot coincides with the main laser beam only at the exact focal distance below the nozzle after painstaking (and easily disrupted) alignment. A red dot laser coaxial with the CO₂ tube / beam should produce much better results, but that’s not what I have.

It Would Be Nice If™ I could cut the card outlines with the laser, print the hole positions on the inkjet, then align the “blanks” for “punching”, but I have yet to find any combination of parameters amid the unsteady ziggurat of Linux / CUPS printing configurations to produce properly aligned results on a custom paper size:

Misaligned punched card printing
Misaligned punched card printing

You might think telling the printer it’s handling a #10 envelope with the image of the text carefully positioned to land at the proper spot on the actual card should work. You (well, I) would be wrong.

I’m pretty sure this can be coerced into working, but it must marinate on the to-do list for a while.

5 thoughts on “Laser-cut Punched Cards

  1. To complete the exercise you need to hand the deck of cards to someone who will return twenty minutes later with a printout that says “Syntax error Line #5.”

    1. Twenty minutes‽ Man, you get fast turnaround from your Comp Center!

      I’d definitely want sequence numbers in columns 72 through 80, too.

  2. Two thoughts:
    1.)
    You could get a cross-hair laser from two laser pointers that produce a line. Just put them on the sides like your current pointer- about 90° offset between them if you’re a stickler for cartesian coordinates- and turn the line, so it hits the main laser. Result is a cross-hair that is independent of distance. If you don’t want to go the china route, HF is kind enough to import them for a little fee: (https://www.harborfreight.com/laser-marker-93242.html)
    Not ideal, it has button cells, but you probably could fashion an adapter.

    2.)
    If you can punch punch-cards, you can also punch cards for music boxes.
    The cheap one: https://www.aliexpress.com/item/1005001489608254.html
    ( around $14 with shipping before I posted this link)
    The deluxe one: “30-Note Tapes Hand Crank Music” (around $26)
    Just make sure, you are done by Christmas.
    You of course still have to write the software that turns midi into grbl, or whatever your laser takes ;)

    1. I have a handful of 5 V line lasers, but mounting the things on the tube without crashing into the side walls poses a challenge.

      LightBurn allows a laser pointer offset, so a single vertical beam would work, as long as I do all the navigation through the PC with the LightBurn UI. This requires more thought; none of the mounts I’ve doodled can actually work.

      Also: perhaps one could gimmick the rotary axis to drive blank paper tape across the platform …

      1. I got one, it takes light card stock. I might try punching strips from manila folders before next Christmas.
        Well, but a laser cutter that feeds paper tape… that would be a music box jukebox :)

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