Investigation of Thermal Effects on Linear Scales

Digital incremental linear encoders are considered as proven and reliable standard positioning measuring systems in CNC-machine tools. A further detailed inspection reveals that such a measuring system consists of a combination of materials, i.e. casting (table of machine tools), aluminum and glass (linear encoder) with different thermal coefficients of expansion. Due to the increasing demand of the accuracy of CNC-machine tools, this sophisticated complex system with its interacting influence of expansion is a fastidious topical research subject. The test equipment, a six metre high precision length comparator which was developed and produced by our department, is located in an air conditioned laboratory.