Fig. 1. Schematic of spiral groove structure machined by ultrafast laser with two dimensional galvanometer

Fig. 2. TN85 cermet. (a) TN85 blank; (b) TN85 spiral groove to be machined; (c) spiral characteristic

Fig. 3. Influence of laser processing parameters on the etching law of cermet. (a) Relationship between etching depth, width, and laser power; (b) relationship between etching depth, width, and laser scanning speed

Fig. 4. Confocal microscopy measurement results of laser grooved on TN85 cermet planar materials

Fig. 5. Path extraction of spiral groove laser processing. (a) spiral groove machining model; (b) spiral groove profile; (c) spiral groove machining path filling

Fig. 6. Machining roughness of cermet spiral groove. (a) Top part of spiral groove; (b) middle of spiral groove; (c) bottom part of spiral groove

Fig. 7. Relationship between depth, width, and defocusing amount

Fig. 8. Schematic of spot overlap ratio of different positions in spiral groove laser processing

Fig. 9. Information extraction module of surface spiral groove

Fig. 10. Sketch map of spiral groove surface segmentation

Fig. 11. Schematic of mutual compensation of spot overlap rate

Fig. 12. Depth measurement of curved spiral groove

Fig. 13. Machining roughness of cermet spiral groove after surface division. (a) Top part of spiral groove; (b) middle of spiral groove; (c) bottom part of spiral groove

Fig. 14. Dynamic pressure air bearing series equiangular spiral groove