Laser interferometer based instrument for 3D dynamic measurements of CNC machines geometry

Abstract

Quick, easy and accurate measurements of the geometry of numerically controlled industrial machines have always been problematic for several reasons. Achieving high accuracy usually means considerable complexity of measurements, long measurement time and not negligible cost of the device. In addition, because users are interested in different geometry parameters, many measuring instruments are usually needed. A kind of industrial standard for geometry tests over years became laser interferometer based instruments. They are very versatile and precise, but in most cases require qualified personnel. Mainly for this reason, a group of instruments based on the principles of beam positioning or short range sensors has been developed. In this article we present an innovative configuration of the laser interferometer in combination with a differential beam position sensor, which is able to provide much more complete data about the behaviour and geometry of the machine than competitive methods in a comparable or shorter time. Moreover, the data obtained in this measurement can be directly used to compensate not only for positioning errors but also for perpendicularity of the machine axis.