Chromatic confocal sensor for in-process measurement during lathing

There is a growing interest in monitoring systems to evaluate the quality relevant features as close as possible to the machining, thereby reduce the time lack between production and measurement. By the establishment of a quick feedback loop the reject due to defects can be minimized because errors in the production process can be detected with close temporal proximity to the machining. However, for implementation of optical sensors near the machining process new concepts and designs are needed to achieve a robust and miniaturized sensor probe. Chromatic confocal microscopy is a promising approach to obtain measurements near the production due to the fact that the height of a point can be determined with a single shot. For this reason a miniaturized design of a chromatic confocal sensor based on gradient index lenses is presented. The modeling and optical design is presented and a layout of a sensor is developed using a diffractive optical element for the axial chromatic split of the light. In a further step considerations of the fabrication process are summarized and first results are presented.