Miniaturized nonincremental interferometric fiber-optic distance sensor for turning process monitoring

For in-process shape monitoring of rotating objects such as workpieces in a turning machine, contactless and compact sensors with high temporal resolution are necessary. For this challenging task, we developed a miniaturized and robust nonincremental interferometric fiber-optical distance sensor with dimensions of only 30×40×90 mm3, which enables attaching the sensor head directly to the mount of a turning tool bit. We present the results of in-process 3-D shape measurements of turning parts at a metal working lathe. To proof the accuracy of the measurement results, comparative measurements with tactile and optical sensors were performed. A maximal deviation between the different measurement methods of 2.2 μm was achieved for the determination of the mean height of a radial step.