Glass / glass laser welding: borosilicate – soda-lime

Guaranteeing a high level of mechanical strength, hermeticity and transparency for a durable joint between two different types of glass, borosilicate and soda-lime, despite their a priori incompatible thermal and mechanical behaviours.

Use of laser transmission welding based on ultrashort pulse technologies. The process has been developed and optimised to enable direct joining at the interface, without filler material, without additives and without global heat treatment.

The main challenge is to ensure a reliable joint between two glass materials with different expansion coefficients, while mastering complex geometries and the formation of volumetric weld seams at the interface. It is also necessary to guarantee the stability of the joint and the absence of internal defects despite the heterogeneity of the materials and the thermomechanical stresses induced by the laser process.

The resulting joint is transparent and homogeneous, with very high mechanical strength and excellent resistance to thermal cycling. The process enables competitive cycle times without post-treatment, while guaranteeing long-lasting hermeticity between dissimilar materials. It also opens up the possibility of integrating additional functions, particularly for information or functionalisation.