Tangential laser turning of fused silica usin ultra-short laser pulsesWednesday (24.06.2020) 13:28 - 13:31 Room 1
Laser turning with ultra-short laser pulses provides the possibility of manufacturing rotationally symmetric geometries even from hard to machine materials as fused silica. Due to its optical, thermal and mechanical properties, fused silica is used in different applications such as, e.g., optics, fiber optics, and semiconductor industry, respectively. Laser turning of fused silica offers a process for fabricating rotational symmetric parts down to a micrometer scale. In this laser micro machining approach, the laser beam is oriented perpendicularly to the rotational axis and tangentially to the material, whereas the target geometry is realized by moving the constantly rotating specimen according to the specified geometry under the focused laser spot. Due to the friction-less laser ablation it is possible to realize a turning process in fused silica without the use of a contacting tool and therefore without causing tensions in the work piece. The cutting head focuses the laser to a spot size of 16 µm in diameter and the applied processing gas pressure assists in removing the ablated material.
In this study, femto-second laser turning of fused silica with a diameter of 5 mm is investigated. The influence of rotation speed and focal spot size upon the overall process speed is stated. Furthermore, comprehensive parameter studies in order to optimize surface roughness and to find the maximum achievable ablation rate are shown. Limited by the mechanical speed of the rotational axis, the highest feasible ablation rate is 19.5 mm³/min. In addition, effects of a trepanning optic that moves the laser spot in a circular motion to spatially distribute the laser power upon the maximum laser feed rate are displayed. Lastly, an experimental series to examine the influence of the applied pulse energy upon the laser turning process is demonstrated.
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|Poster||Version 1||Laser turning of fused silica. Study of ablation rate and efficiency for different pulse energies and trepanning diameters.||1 MB||Download|