Advanced modelling of the dynamic behaviour of HSM spindle
High Speed Machining (HSM) has significantly increased productivity and workpiece quality. It requires high speed and high power spindles. They are a cluster of technology and the most interesting and efficient machine-tool component. They represent one of the most critical bearing applications. Besides, the process has become more complex. Indeed, with spindle speeds higher than 15 000 RPM, many problems may occur. The dynamic behaviour of the tool-spindle assembly is crucial. Any incident, such as a cutter breakage or severe machining vibrations, can damage the spindle . It results in very low spindle lifetime, mainly due do to inappropriate cutting conditions . This increases the cost of the workpieces. Therefore, an accurate comprehension of the spindle dynamic behaviour is required, in order to optimise machining operations [3-6].
During the F.U.I. project UsinAE, the MO2P team of IRCCyN lab has studied lifetime issue of HSM spindle, with Precise and Fischer spindle manufacturers. This collaboration goes on with the F.U.I. project QuaUsi, concerning the accurate modelling of the spindle dynamic behaviour and the study of the impact on workpiece quality.
The present Master subject is funded by this new project and is a continuation of David Noël Ph.D. He has developed a 5DoF bearing model that considers a number of technological aspects of spindles, including the dynamic effects at high speed in a preloaded bearing arrangement . Specific instrumented experimental devices have been developed. It allowed the model updating and enrichment of the preloaded bearing arrangement. It was then used as limit conditions of the rotor dynamic model .
The Master work consists in developing spindle simulation model, experimental process and the model optimization so that the simulations comply with real experimental data. It deals with spindle rotor bending and the evolution of the Frequency Response Function in relation to spindle speed. Non-linearity of bearings model is considered. Mechanical systems adjacent to the rotor will be modelled. CATIA and LMS Virtual.Lab will be used for multi-body dynamic computations based on real CAD part models. The tool-spindle model will be validated experimentally for different tool geometry.
The model simulation results will be compared to the results of instrumented experiments, in industrial conditions and using the specific devices developed by IRCCyN lab. Experiments will be carried out at Technocampus EMC2 or in plants of aeronautic manufacturer partners.