I ordered a bunch of square spice bottles to laser. The actual width of these is 2.04" so I ended up engraving at 0.04" out of focus…which ended up being pretty bad. The engrave is really lumpy, which seems like I need either more speed or less power. Near the end of the engrave the glass fractured from the heat stress.
Focal depth 0.500
Did you use any “coating”? Usually if I notice a “unsatisfactory” engrave on a piece, I leave it in the , copy the design multiple times on the object with different setting of various dgrees to use as my “test” . Then see what works best before putting another new piece in… you can even label the piece (sharpies) with the various settings as your “example” or “sample” piece (you may want that “lumpy engrave” as part of a project some day).
In my testing, albeit very limited, I’ve found I didn’t need to go anywhere near that slowly. As a matter of fact, I’ve used 1000 with great results. Power, on the other hand made a huge difference. Full seem to me to be the only way to go, just as you’ve done.