Measurementand identification of dynamic translational stiffness matrix on machine tools understatic preloads

Dynamic stiffness is an important characteristic of production machinery, as it contributes to its ability to maintain the position ofthe tool centre point accurately and precisely under loads. For machine tools, it directly affects the geometric dimensions and surfaceproperties of produced parts. This work presents a measurement procedure for identification of the full translational dynamicstiffness matrix for a single configuration of a machine tool under loaded conditions. The measurement procedure consists of inducinga static baseload with superimposed dynamic loads, which were controlled in magnitude and direction, at the tool centre point ofthe machine tool. The measurement procedure uses the Loaded Double Ball Bar and measures the dynamic displacement with threeNon-Contact Capacitive Probes. The measurement procedure is implemented in a case study on a 5-axis machining centre.Finally, the manuscript concludes with a discussion on the utility value of the translational dynamic stiffness matrix for the designand operation of machine tools as well as the possibility to expand the measurement procedure to capture the dynamic stiffnessusing quasi-static movements of the machine tool.QC 20211117