Influence of spindle design parameters on the dynamic stability in end-milling operation
Keywords:
Spindle dynamics; Stability; Bearing contact forces; Timoshenko beam element; Solid modeling; Bearing preload.Abstract
This work presents a combined model of high acceleration end-mill spindle system by
considering the dynamics of angular contact ball bearings and cutting forces. At first the the
spindle unit is analyzed by taking into consideration the centrifugal as well as the gyroscopic
conditions using Timoshenko finite aspect model. Hertz bearing contact forces are
considered at the front and {back|rear end} ends of the spindle. Frequency response
functions at the tool-tip are obtained from the dynamic spindle model. In the second phase,
solid model of the device is developed and their dynamic response is obtained from 3d finite
factor analysis. After, verification of the results with beam theory, the stability lobe diagrams
are obtained from tool-tip frequency response functions (FRF) for different tool-overhang
lengths, bearing span values and bearing preload conditions. A neural network based
observer is designed based on the simulation results.
