When engraving glass, some letters do not engrave for 2-3 seconds. The first pass is invisible, only the next ones engrave the glass. Sometimes the engraving is done on the other side of the glass wall. Using paper like for CO2, the engraving is perfect. I bought UV so as not to use paper. Are my parameters ok?
With the smaller spot size and smaller wavelength of UV, your focus range is very small. Check the “parallelness” of the head to to the base, and make sure your stock is very flat.