Dynamic characteristics of the Lawrence Livermore National Laboratory Precision Engineering Research Lathe

Abstract The dynamic characteristics of the Precision Engineering Research Lathe (PERL) have been investigated experimentally, up to a frequency of 1,000 Hz. In successive tests, the exciting force was applied to either the x-slide or the (nonrotating) spindle, and in the x- or z-direction. These are the critical directions for turning operations on this T-base type lathe. Each of these tests was furthermore done with the servo system active and with the servo system off (slides clamped, control loops open). The applied force fluctuations and the resulting relative displacement, between a capacitive probe mounted on the x-slide and the spindle, were measured during the experiments. From these data, the relative dynamic compliances between the tool and the workpiece, in the z- and x-directions, have been determined. The resonant frequencies, modes, and compliances that significantly influence the surface quality of the parts turned on this machine are reported.