Femtosecond Laser micromachining of Various Materials for Industrial Engraving Applications

Femtosecond laser engraving offers a new avenue for ultimate precision, cleanliness, versatility and supreme quality compared to the already stabilished engraving lasers such as nanosecond or CW CO 2 lasers. Thanks to their non linear light-matter interaction nature it allows not only ablation with negligible thermal effects but also in a wide amount of diferent materials. This later advantage is of special interest for flexible multimaterial engraving which is desired in several industrial sectors. For such purposes, a proper parameter study should be employed for each material in order to achieve highest quality. There are several studies addressing ablation efficiency in several materials [1] , [2] , but this number narrows when other remarkable parameters such as roughness or taper angle are analyzed [3] . This lack of material studies is increased even more for less common materials and when high depth is desired. In this work we have performed a smart parameter optimization of SiC, PEEK and sapphire. The influence of fluence, overlap ratio (OP) and Pulse Repetition Rate (PRR) on roughness, depth and taper angle is discussed. For such purpose, parameter study has been performed employing an Yterbium doped fiber laser from Fibercryst ( λ = 1030 nm , τ = 400 fs ) where a galvo-scanner that passes light trough an f− 0 lens with f=170mm ( ω 0 = 21 µm ) allows 2D inscription faster than a movable stage. Inscriptions were performed at diferent PRRs and OPs. The overlap ratio was changed while maintaining same irradiation time, i.e. compensating lower OPs by increasing scan number.