Full Version: Substrate Surface Variation...
From: Boz (CHEDDARHEAD) [#6]
20 Dec 2006
To: ALL
Rule of thumb for depth of field of focused laser beams through a lens
1.5" fl lens - maybe .100"
2" fl. lens - maybe .200"
4" fl. lens - maybe as much as 3/8"
I have gotten away with these kinds of depth of field variations on some materials when engraving. If your graphic is not too detailed, you might be able to get away with a little more. Now for vector cutting, you probably won't get away with as much. Your cut quality through a piece will change drastically as you move away from the focus point.
When I am cutting something thicker than 1/8" thk., I usually run my focus point about a third of the way down into the material. This helps keep the edges of the cut a little straighter.