Linear Magnetic Bearings/Actuator Design and Prototype for High Precision Spindles

In precision manufacturing, magnetic thrust bearings can be advantageously used to provide both high axial stiffness and short-stroke axial in-feed motion for precision spindles. This paper presents the design, analysis, prototype, and experimental results of a compact radially-biased magnetic thrust bearing with linear force characteristics. The first prototype of the thrust magnetic bearing demonstrates less than 5 nm RMS positioning noise over 1 mm stroke and 1500 Hz closed-loop bandwidth. The actuating force is over 300 N at continuous working condition and a maximum of 600 N.