Glass is best marked with UV or CO2 laser systems. The energy input can be kept low to minimize the effect of microcracking.
Both marking methods create easily readable and resistant characters by means of engraving or colour change, which are optically different on closer inspection. While the UV laser marks are even, finely rasterized areas, the resolution of the CO2 marking appears in coarser pixels.
In the production process, the CO2 laser proves to be faster. With the 30-watt CO2 laser system used here, the marking shown on a shot glass for the FOBA sample case could be created in 46 seconds. The same marking took just over two minutes with the V.0020-uv system with an energy input of 2 watts. In both cases the focus shift must be adjusted to the shape of the glass.