This page describes a laser engraving setting published for Marbre / granit at 8 mm, tested on a Longer Nano Pro 12W fitted with a Diode 12W source (445 nm blue diode, 12 W). It states the exact machine, source, material, thickness and operation of the test; power, speed and number of passes are shown with a Premium pass.
Why those four facts matter: a engraving setting that works on Marbre / granit at 8 mm does not transfer to another thickness, nor to another source. A 445 nm blue diode rated 12 W does not deposit the same energy as a stronger module, and the speed has to be adjusted accordingly. Copying a number without checking those four points is the first cause of a ruined part.
Published by LaserSettings (estimation). No other workshop has confirmed it yet: treat it as a starting point, and confirm it from your account if you reproduce it.
No photo comes with this setting yet. If you reproduce it, publish yours from your account: a picture of the result is worth more than a line of numbers.
Recommended routine before running the part: clean the lens, redo the focus, engrave a small test grid on an offcut of the same Marbre / granit, then adjust the speed rather than the power. Work with fume extraction and air assist, wear glasses rated for 445 nm blue diode, and never leave the machine unattended.
Longer makes entry-level diode engravers and higher-power module models, with a touchscreen and aluminium frame. They engrave light wood and leather cleanly; on acrylic, only opaque colours react, as with any blue diode.
Marble and granite engrave like slate, by flaking off a thin surface layer. On dark polished stone the result is a bright, very durable white — the technique used for memorial plaques.
Stone is never laser-cut. When engraving, the stone's own contrast decides the result: polished black granite gives a brilliant white, veined white marble gives weak and often disappointing contrast.
High power, fast speed, a single pass. A second pass re-burns the dust and greys the white you achieved.
Polished stone gives far more contrast than raw or honed stone: the engraved white cuts against the gloss.
No toxic fumes, but very fine mineral dust not to be breathed: extraction on, and wipe with a damp cloth rather than an air gun.
A heavy slab will not move, but check flatness: on a slightly domed slab, contrast varies from edge to edge.
To strengthen text, black wax or paint applied then wiped flat fills the recesses and improves legibility further.