On-machine measurement system of ultra-precision lathe for brittle material machining

Abstract

This paper presents on-machine measurement system of ultra-precision lathe. The work piece in this study is a brittle material, such as optical glass. To establish a technique of crack free machining of brittle materials, nano metric tool controlling for material is necessary. The on-machine measurement before cutting is very important to decide precise tool feed. From the measurement data, the profile generation data not to propagate crack can be decided. However, the on-machine measurement system was set to the ultra-precision lathe, It was still difficult to connect correctly between the measurement data origin and the cutting data origin. When we use the center point of rotating main axis as datum point, we can connect measurement data and cutting data. Then in this study, we propose new method to detect center of rotation using the flat skew surface and on-machine measurement sensor. Experimental results showed good detecting for center of rotation and its repeatability was 0.01mm. The cutting data was decided from measurement result and profile generation experiment performed. The minute pattern over optical glass without any crack was obtained, and this showed the efficiency of our proposal method.