Conference Papers
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Item Dynamic characteristics of drilling spindle supported by radial permanent magnet bearings(Elsevier Ltd, 2020) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.This paper presents the drilling spindle dynamic and harmonic characteristics supported by radial permanent magnet bearings (PMBs). Initially, multi-ring radial PMB is designed in proportionate to the dimensions of drilling spindle using Coulombain model and vector approach. Dynamic analysis of spindle is carried out for three different combinations between conventional angular contact bearings (ACBs) and PMBs. First, the spindle was supported by only ACBs. Second, ACBs were completely replaced by radial PMBs and one ACB was used in between two PMBs making it as a hybrid bearing set (HBS) in the last case. The effect of bearing preload, bearing span and cutting force on the spindle natural frequency, harmonic frequency and critical speed of drilling spindle system was investigated through rotor dynamic analysis. This analysis focuses on the feasibility of successful usage of HBS in drilling machine spindles with higher critical speeds and maximum amplitudes produced due to chattered vibrations and tangential cutting forces. © 2019 Elsevier Ltd.Item Dynamic and harmonic analysis of pillar drilling machine spindle supported by hybrid bearing set(American Institute of Physics Inc. subs@aip.org, 2020) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.The objective of this work is to study the dynamic and harmonic response behavior of drilling spindle supported by hybrid bearing set (HBS). HBS consists of an angular contact bearing (ACB) and radial permanent magnetic bearing. Dynamic and harmonic analysis was performed in order to investigate the effect of bearing stiffness and thrust force on the natural frequency, critical speed and vibration amplitude of a drilling spindle system. In the first step, analyses were carried out for the spindle system supported by conventional ACB's considering the effective bearing span length. In the second step, the dynamic and harmonic responses were analyzed for the drilling spindle system supported by HBS by replacing conventional ACB's. The dynamic performance of spindle under ACB's and HBS is investigated systematically using Ansys rotor dynamic and harmonic response tool. This research highlights the feasibility of effective usage of HBS in drilling machine spindles with higher critical speeds and maximum amplitudes generating due to cutting forces. © 2020 Author(s).Item Evaluation of Dynamic Characteristics of a VMC Spindle System Through Modal and Harmonic Response. Part 1: Spindle Supported by Angular Contact Ball Bearings(Springer Science and Business Media Deutschland GmbH, 2021) Chalageri, G.R.; Bekinal, S.I.; Doddamani, M.Machine spindle dynamic characteristics are precisely related to the operation and stability of the machining process. The finite element analysis (FEA) has been used to find out the dynamic behavior of spindle-bearing system. The unbalance response of the vertical machining center (VMC) spindle system at the cutting tool due to thrust force is calculated to study the dynamic properties. In this paper, Ansys Workbench rotordynamic and harmonic response have been used to make the dynamic investigation of VMC spindle and estimate the final values. Results show that the obtained critical speeds are nowhere near to the spindle operating speed range; hence, the resonance would not occur, and at operating speed, the maximum unbalance response is within an acceptable limit. The effect of rotordynamic and harmonic response on same VMC spindle system supported by hybrid bearing set is analyzed in Part 2 as an extension of this work. © 2021, Springer Nature Singapore Pte Ltd.