Measurement of mid spatial frequencies of diamond turned optics by using dual-mode snapshot interferometry

The measurement of mid-spatial frequency (MSF) in ultra-precision machining is crucial for assessing the quality and performance of machined surfaces. The sources which contribute to MSF errors during diamond turning are vibrations and dynamic instabilities, tool wear and deflection during cutting, inconsistent feed rates, variation in material properties, incorrect machine settings/process parameters, material removal mechanism employed. Controlling & measuring of mid-spatial frequencies in the diamond turning process is essential for meeting stringent optical specifications in various applications, such as lens manufacturing for imaging systems, telescopes, or laser systems etc. The inspection of MSF errors offline, or after the manufacturing process, is a common practice in quality control of optical surfaces. In this study, the influence of material properties and its impact on the mid-spatial frequencies during diamond turning is studied by using on-machine metrology (OMM).OMM provide real-time feedback which helps in adjusting machining parameters to correct deviations and maintain the desired mid-spatial frequencies.