Int J. Math Tool Des Rcs VoL 24. No. 3. pp. 2(17-214. Iqb:4. 110211-7357 ~,4 Sit z, t~lt ~ lilt Prtnted in Great Britain Pergamon Press Lid SUPPRESSION OF SELF-EXCITED VIBRATION BY THE SPINDLE SPEED VARIATION METHOD K. JEMIELN1AK and A. WIDOTA (Received for publication 26 January 1984) Abstract--A method for the analysis of the influence of spindle speed variation on the course of self-excited vibration has been presented. This analysis is based on the influence of the frequency of self-excited vibration on the stability of machining, and dependence of this frequency on workpiece rotational speed. The influence of the spindle speed variation frequency and amplitude on chatter has been investigated. a alirn C C,, C, dL K Kx Ke M,, N N,, N r Na N1, N,_...NM T R x(t), x(r- 73 x,. xr X. X1. X>..XM s fp,, ~N 03 0 OOt. O) T tOO OJ I , tO2.. .tO M NOMENCLATURE depth of cut limit depth of cut at constant rotational speed of workpiece damping of dynamic system of machine tool (DSMT) damping of the machine tool system damping of cutting process incremental feed force component stiffness of DSMT stiffness of cutting process stiffness of the machine tool system mass of the machine tool system workpiece rotational speed workpiece rotational speed in present and previous revolution of the workpiece workpiece rotational speed before putting the SSV into operation workpiece rotational speeds in succeeding revolutions of the workpiece after putting the SSV into operation period of the workpiece revolution stability limit exceed factor tool displacement relative to workpiece (parallel to the feed direction) in present and previous revolution of the workpiece amplitude of vibration in present and previous revolution of the workpiece amplitude of vibration before putting the SSV into operation amplitude of vibration in succeeding revolutions of the workpiece after putting the SSV into operation relative frequency of the SSV relative amplitude of the SSV amplitude amplification coefficient damping ratio of DSMT frequency of vibration natural frequency of DSMT frequency of vibration in present and previous revolution of the workpiece frequency of vibration before putting the SSV into operation frequency of vibration in succeeding revolutions of the workpiece after putting the SSV into operation INTRODUCTION THE SUVPRESSION of self-excited vibration may be performed by many methods. One of them is the spindle speed variation (SSV) method, where the spindle speed is periodically varied. The idea of the SSV was presented by St6ferle and Grab in [8]. Since that time there have appeared several publications presenting the results of research of the SSV influence on the self-excited vibration [1-4,6-8]. These papers formulated Institute of Production Engineering, Warsaw Technical University. ul. Narbutta 86.02-524 Warsav,. Poland 207