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.

The New Hotness

  • Craft Stick Plant Markers: Laser Fixture

    Converting craft sticks into plant markers should be a mass-production process, which means a fixture is in order:

    Craft Stick Markers - fixture first fill
    Craft Stick Markers – fixture first fill

    Admittedly, making ten markers at once barely qualifies as “mass production”, but you (well, I) can think of it a proof of concept.

    The basic shape comes from a 0.25 mm outset around the measured size of a craft stick (150×18 mm), plus an alignment target:

    Craft Stick Plant Markers - fixture cut layout - array base
    Craft Stick Plant Markers – fixture cut layout – array base

    A good rule of thumb says never do any more work than absolutely necessary, so the rest of the fixture comes from linear arrays replicating the stick slots and targets:

    Craft Stick Plant Markers - fixture cut layout - full
    Craft Stick Plant Markers – fixture cut layout – full

    The two strips over on the left (with a common cut down the middle) get glued to the underside of the fixture:

    Craft Stick Markers - fixture rail gluing
    Craft Stick Markers – fixture rail gluing

    They’re exactly 5 mm apart to bracket one of the knife-edge bars supporting the fixture. The bar is upside-down to put its flat side upward:

    Craft Stick Markers - fixture target detail
    Craft Stick Markers – fixture target detail

    Yes, the fixture is made of chipboard, mostly because it’s about the same thickness as a craft stick and it’s cheap & readily available. Each target gets an ink blot to make it more conspicuous; there is also a tiny hole burned through the chipboard at the center to mark the other side for the strips.

    Two knife-edge bars (sharp side up) support the sticks near their ends, well out of the cutting path, to prevent scorch marks:

    Craft Stick Markers - fixture overview
    Craft Stick Markers – fixture overview

    It’s worth noting the knife-edge bars are 5 mm wide and the platform spaces them on 3/8 inch = 9.525 mm centers. Not 10 mm, not 9.5 mm, exactly 3/8 inch. Kinda like the platform leadscrews: a 4 mm lead thread driven by a belt with 0.2 inch pitch. Only in America.

    This doodle captures the key dimensions down there in the corner to work out where the strips should go:

    Craft Stick Plant Markers - fixture vs laser bar spacing doodle
    Craft Stick Plant Markers – fixture vs laser bar spacing doodle

    Now, to convert names from a garden map into plant markers …