Abstract
A high speed (25,000 rpm) routing machine with a 300 lb rotor was designed and manufactured. To accommodate the high shaft speed, 2.6 million DN, rolling element bearings were used with ceramic balls and inner races. In order to control the magnitude of the vibration, damping was incorporated into the system using nonrotating hydrostatic dampers. The journal for the dampers was a cylindrical cartridge that had the rolling element bearings clamped inside of it. Extensive analysis was performed on this system. A computer program was written that could model the orbit path of the lumped mass shaft in the damper over the full speed range. A second program was also written that calculated the damper nonlinear stiffness and damping coefficients, and incorporated them in with a one-dimensional beam, finite element rotordynamics model of the system. Analysis results are presented along with experimental run data from the machine. Balancing problems encountered during commissioning have limited the results to 16,500 rpm to date. The last of which is currently being remedied.
