Machining, Measurement, and Control Laboratory

Development of Dynamic Loading Device for Rotating Spindle of Machine Tools
Ryota Sawamura, Shinya Ikenaga, Atsushi Matsubara

High performance milling spindles, which have high rigidity and high speed, are required for high productive machining. In order to evaluate the rigidity change of the spindle, authors has been developed a magnetic loading device. This device provides attractive force in radial direction to a dummy tool attached to a spindle. By using this device, the static stiffness of the rotating spindle has been successfully evaluated. However the loading rate could not be controlled due to the electric response lag caused by the magnetic field. To solve this problem, electric response of the coil-tool system with the air gap is analyzed and the dynamic response is estimated. The air-gap's influence on the load was also evaluated. Based on the analysis, a dynamic loading test is designed carried out for the measurement of the rigidity of a machine tool spindle.
Keywords: Machine tools, Spindle, Stiffness, Loading.