Thermoelectrically tempered motorised spindle for high-precision machine tools

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 529738427

In the field of high-precision (HP) and ultra-precision (UP) machining, high demands are placed on the dimensional accuracy of the components down to the submicrometer range. An important field of application for such high-precision components is medical technology, the aerospace industry and toolmaking. The thermal behavior of the motorised spindles used for HP and UP machining in machine tools plays a crucial role in achieving the required working accuracy. Up to 75 % of geometrical errors are caused by thermally induced displacements of the tool center point. As a result of electrical and mechanical power losses of the motor and the bearings, heat flows are induced, for example, into the shaft and the housing of the spindles. These lead to increasing temperatures and consequently to thermally induced deformation of the corresponding components. Variations in the induced heat flow are unavoidable, e.g. due to the change of tool or workpiece as well as adjustments to the rotational speed. In order to maintain the required tolerances in the area of HP and UP machining, this leads to long warm-up periods of the machine tools until a thermal steady state is reached. The use of Peltier technology for temperature control is intended to increase the thermal stability of a motorized spindle and reduce its warm-up period compared to the state of the art. For this purpose, a novel thermoelectric cooling system based on tubular Peltier modules is to be developed and integrated between the heat sources and sinks of a motorized milling spindle. This will enable a controlled removal of heat from the bearings and the motor of the spindle.

• DFG Programme: Research Grants (Transfer Project)
• Application Partner: Dr. Neumann Peltier Technik GmbH; Nakanishi Jaeger GmbH
• Cooperation Partner: Dr.-Ing. Olaf Schäfer-Welsen