Reliability analysis of machine tool spindle-bearing system using XLrotor

In rotordynamic analysis, a simulation tool is required for design and optimization of a rotor system. The forces generated are high when the rotary system is operated at high speeds and probability of failure is also high with minor imbalance. The imbalance in rotating machines is major concern that varies with time causing misalignment, looseness, bent shaft, and bearing failures. The amplitude at critical speeds is high due to imbalance in rotor that exceeds vibration levels beyond acceptable limits of ISO 10816-1 vibration severity criteria, resulting in failure. The critical speeds can be shifted for low-speed rotor with change in mass and stiffness effectively, but for high speed rotor, the critical speeds are bypassed with reduced amplitude of vibration by changing the bearing stiffness and damping properties. An attempt is made on reliability analysis of machine tool spindle with bearings (rotor model with bearings) system using computational tool XLrotor. The amplitude of vibration of spindle machine tool is controlled which results reduce in failures and increase in reliability. The results are determined through XLrotor due to its ease of use and less time for customization of rotor models which shows good agreement with FEM results. In this paper, the rotor is operated from 2000 cpm to 28,000 cpm, and the undamped critical speeds, Campbell diagram, vibration levels at imbalance, and load on bearings at peak amplitude are determined.