Method for determining the angle of the normals of a specimen rotating about a fixed axis of rotation and measuring machine for carrying out the method

摘要

In a method for determining the azimuthal angle of the normals to a specimen rotating about a fixed axis of rotation, use is made of a light beam which falls upon a light detector in accordance with the respective azimuthal angle of the specimen. The light beam has a small aperture angle and a small cross-sectional area and is emitted in a manner intersecting the axis of rotation of the specimen. The arithmetic mean is formed from two adjacent azimuthal angles at which there is in each case a variation in the intensity of the light beam, i.e. a lightening or darkening of the light beam, and this mean represents a measure of the azimuthal angle of the normals.