Fig. 1. Online measuring system for cutting force in deep hole machining of quartz prefabricated bar

Fig. 2. Block diagram of acquisition program for LabVIEW host computer

Fig. 3. Schematiz diagram of CL-YD303 piezoelectric sensor

Fig. 4. Structure of force measuring fixture

Fig. 5. Experimental setup for deep hole machining of quartz prefabricated rods

Fig. 6. Diamond hollow tool

Fig. 7. Zoom microscope images of diamond hollow tool

Fig. 8. Cutting force signal pre-processing

Fig. 9. Relationship between average cutting force and drilling depth

Fig. 10. Spectra of cutting force signals from experiment 1， 2 and 3

Fig. 11. Cross section of quartz precast bar after machining

Fig. 12. Surface morphology of glass mandrel under tool with different wear degrees

Fig. 13. Variation of surface roughness of three tool states with cutting force

Fig. 14. Internal fracture of panda polarizing fiber