My girlfriend and her coworker designed these to give out as gifts to their artists. My friend (who owns the glowforge) and I thought laser etching was gonna me much faster than hand wood burning the letters. The drawings we decided would just be transferred (laser printer + transfer pen) to retain their color and for speed. As we found out, raster etching even the letters was gonna take fooooorever. Per coaster side, raster was 12+ minutes. We could fit 11 coasters inside the Glowforge at once, so 2+ hours per side per group. Total number of coasters was like 70, so we had many groups! This wasn’t gonna fly so we decided to try the hack of defocusing the laser and creating nested offset vectors. This made each coaster group about 30 mins. At least 4x faster, but probably a bit more.
So the only downside we experienced was dots at the corners where the laser changes direction and the laser power is constant (we think). I hear GF now has variable laser power for changes in direction, but we haven’t had a chance to test that feature out, yet.