Mechanical properties of fused silica flexures


Fused Silica flexure under testFused Silica flexure under test

Professor Yves Bellouard, Mechanical Eng. Dept., Eindhoven University of Technology (Eindhoven, The Netherlands) recently reported on the mechanical properties of fused silica flexures manufactured with our femtoEtch process. Flexural strengths as high as 2.7 GPa were measured.

Although fused silica is intrinsically a very strong material, it has never been used to fabricate mechanical flexures due to the absence of a suitable machining technique capable of generating the desired geometric profile, while at the same time preventing the formation of surface defects. These surface flaws act as stress concentrators and cause the nucleation of cracks, which ultimately lead to failure [1]

This limitation has been lifted with the femtoEtch method, where a combination of femtosecond laser activation and chemical etching thwarts the formation of cracks, while providing a method to fabricate geometrically complex shapes.

Professor Bellouard tested fifteen femtoetched fused silica micro-hinges. In all of the specimens measured, the breaking strength was at least an order of a magnitude higher than the recommended design stress for fused silica parts. In fact, fourteen out of the fifteen, measured well above the typical breaking strength values for common engineering materials


1. M. Tomozawa, “Fracture of glasses,” Annu. Rev. Mater. Sci. 26(1), 43–74 (1996).