Laser welding of glass requires low thermal conductivity of the material which creates high temperature gradients when heated up locally and hence may involve a breakage. After pre-heating the material the laser process can be optimized in order to control the risk of breakage. Using a defocused laser beam reduces the temperature gradient within the welding zone. Scanner heads or rotary axes for cylindrical workpieces allow fast multiple passes over the entire weld contour ensuring a consistent temperature level throughout the complete welding seam. For laser welding of glass, CO2, Nd:YAG or diode lasers are the lasers of first choice. Compared to other joining techniques it benefits essentially from the sterile surface quality.
