Lines problems. Some guidance, please

[Kaito.pt (Carlos Ribeiro)]

Hi. I’m new to this laser engraving world and I’m looking for help from you.
My laser is a Totem S diod 5.5w laser.
I’ve made some tests on white tiles painted black (see pictures) and I’m getting darker lines in some parts of the design.
Both design are pure black and white, engraved with the same settings: 900 mm/min, 70% power, 318 dpi, 0.08 mm line interval.
As you can see on Baby Yoda ear there are some darker lines who also appears on the owl design at the same “height”.
What could be causing this?

[rolfw20 (Rolf Wiegmann)]

Seltsamer Effekt. zuerst musst du testen ob es an deiner Maschine oder Lightburn liegt. Haben die Fliesen an der gleichen stelle gelegen? Wenn ja, mach einen Versuch ein paar cm versetzt. Bleibt der Fehler an der gleichen stelle im Bild wird der Fehler in der Software liegen. Wenn nein, musst du deine Maschine untersuchen.

[Bonjour (Bo)]

@Kaito.pt

Hi. I’m new to this laser engraving world and I’m looking for help from you.
My laser is a Totem S diod 5.5w laser.
I’ve made some tests on white tiles painted black (see pictures) and I’m getting darker lines in some parts of the design.
Both design are pure black and white, engraved with the same settings: 900 mm/min, 70% power, 318 dpi, 0.08 mm line interval.
As you can see on Baby Yoda ear there are some darker lines who also appears on the owl design at the same “height”.
What could be causing this?

Inconsistent coating, most likely.

Such a low-powered laser only needs a tiny variation in the depth of coating to give a different result. Inspect the object before removing it and if you get such results, run the pattern again.