Monte Carlo simulation of the manufacturing tolerance in FDBs to identify the sensitive design variables affecting the performance of a disk-spindle system

Abstract

This research proposes the Monte Carlo simulation for manufacturing tolerances in major design variables of fluid dynamic bearings (FDBs) to identify their sensitive design variables on the performance of FDBs and the dynamic performance of a disk-spindle system. Friction torque and critical mass were chosen as the performance indexes of FDBs and the disk-spindle system. The proposed method was applied to the FDBs of a 2.5aEuro(3) HDD, and the Monte Carlo simulation was performed for 16 major design variables of the FDBs. The clearance of the journal bearing was the most sensitive design variable of both the friction torque and critical mass. Additionally the groove to groove and ridge ratio and groove depth of the grooved journal bearing, which were manufactured by electrochemical machining, were also sensitive to determining the friction torque and critical mass of the FDBs, respectively. This research can be utilized to manage the manufacturing tolerance of FDBs to maintain consistent performance of FDBs and a disk-spindle system in an HDD.