Investigations on the influence of process vibrations in CNC grinding processes on the surface quality of fused silica components

The investigations carried out deal with real-time evaluation and recording of vibrations during a CNC grinding process, as well as the analysis and control of process influences on the surface quality of optical components. The experiments were carried out on a 5-axis CNC machine. At the beginning, in planar grinding experiments the present vibration is detected with state-of-the-art vibrometric and optical measurement technology from Polytec. It enables in-process recording of the process vibrations and rapid subsequent topography analysis with the aid of white light interferometry. The measurements aim is to reduce the surface deviations (roughness, mid spatials, waviness) influenced by process vibrations. By carrying out a detailed modal analysis of the CNC machine used, it is possible to detect vibrations and vibration transmissions on the machine and to derive the necessary sensor concept a nd setup. Initial in-process measurements with the aid of a fiber vibrometer showed that the vibrations detected during the grinding process correlate to a high degree with the recorded topography data. It is thus possible to find the characteristic vibrations dependent on the grinding parameters as surface structures on the components, which makes it possible to predict the surface quality produced in the process.