Simulative investigation of point diffraction interferometry with regard to machine tool calibration

One major effect that can deteriorate the geometric accuracy of a calibrated machine tool is the elastic deformation of its structure due to heat transferred into it. Different solutions to this problem have been presented in the past—e.g. temperature-controlled structural parts and environments—but they are complex and expensive. In an on-going Collaborative Research Centre funded by the German Research Foundation scientists are working on model-based compensation and correction strategies. In this paper, a different approach is discussed using point diffraction interferometry to directly measure the three-dimensional distance between tool centre point and workpiece coordinate system. Commercially available three-dimensional measurement systems are introduced representing the state of the art before explaining the basics of point diffraction interferometry. Different parameters are investigated using simulation tools and the achievable accuracy of the approach is evaluated. Additionally, some suggestions are made concerning hardware requirements of a planned demonstrator.