Metrological analysis of a mechatronic system based on novel deformation sensors for thermal issues in machine tools

The precision as well as the production rate of machine tools are starkly dependent on thermal issues. In order to minimize this influence, manufacturers are bound to warm-up procedures before production can begin, so that the machine tool thermal state has stabilized. On the other hand, design optimization and cooling techniques cannot eliminate all errors and call for higher investment costs for the machine tool user. Either through acquiring a new, thermally stable machine or through higher energy consumption, these measures are also not always applicable. Hence, it remains the task for a mechatronic system to capture as much information as possible about the thermal state of the machine tool and take corrective measures during production. A novel mechatronic system that measures directly the thermally induced deformations has been developed to fulfil this task. The measurement uncertainty, as well as the reliability of this mechatronic system are the two crucial properties that define whether this can be applied successfully in the industry. This paper summarizes the investigations on the measurement uncertainty of the proposed system, both analytical and experimental. The functionality of the system was verified on a second test rig, as well as on a vertical machining center, which build the basis for future reliability analyses.