Laser settings for stainless steel

Before any number, decide which surface you are marking. Bare stainless is marked by heat in the steel itself; a marking spray is a coating that the laser bonds to the steel; a powder coat or paint is removed to show the steel. Each one has its own laser, its own risk and its own settings — and the maker rows above mix the first two without saying which.

CerMark LMM6000 is TherMark’s black for metal. Its data sheet says it gives the darkest marks on stainless and works equally well with CO2 and solid-state lasers, but that its process window is somewhat narrow — the sister product LMM14 is easier to use and marks stainless almost as dark (TherMark). The sheet does not mention diode lasers. Creality says a blue diode usually needs a spray, coating or paint on stainless, so diode owners do use sprays — but we found no spray maker’s diode numbers, so treat it as a test.

A tumbler turns under the beam on a rotary. Enter the right diameter: too large stretches the artwork and too small squeezes it, and the cup has to sit level so the focus stays put (GRAPHICS PRO). Tapered cups need the taper accounted for — the rotary calculator works out steps per rotation, mm per rotation and taper.

• Powder-coated: the laser removes the coat and shows the steel. Change speed before power; extra energy after the coat is gone leaves dark “haloing” edges. On CO2, 400–600 DPI gives sharp edges without extra heat. Some colours and textured coats need different settings, and batches vary — run a small grid on each new style. A degreaser wipe brightens the exposed steel; a second pass can clear leftover coat but is not ideal. Ion-coated (coloured) steel under the powder can be discoloured or burnt off by some settings (GRAPHICS PRO).
• Bare stainless: a fiber laser’s job (next section). On a diode, use a marking spray (above).

Hobby fiber lasers are usually galvo machines: speed in mm/s, plus a pulse frequency in kHz. One trade-magazine example for a stainless tumbler is 3,000 mm/s, 60 % power and 65 kHz, for a dark mark without overheating the metal around it; run too slow or with too much power and the steel discolours (GRAPHICS PRO). The article does not give the wattage.

Put it on our scale anyway. If that were a 30 W source: 30 W × 60 % ÷ 3,000 mm/s = 0.006 J/mm — roughly 1/60 to 1/270 of AtomStack’s A-series diode rows for brushed stainless above (0.35–1.6 J/mm). The fiber’s light is absorbed by the steel and arrives in short, intense pulses, so average energy per mm does not carry across laser types; our power & speed converter only compares lasers of the same type. Two more traps: diode software usually shows mm/min and fiber software mm/s, so a copied number can be 60 times off; and for a 20, 30 or 50 W fiber, start from your machine’s own library and scale between fiber wattages, not from a diode row.

Test on the same steel with the same finish: brushed, polished and coated surfaces all behave differently.