Dynamic characteristics of the LLNL precision engineering research lathe

The dynamic characteristics of the Precision Engineering Research Lathe (PERL) have been investigated experimentally, up to a frequency of 1000 Hz. In successive tests the exciting force was applied to either the X slide or the (non-rotating) 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. The relative dynamic compliances between the tool and the workpiece in Z and X direction have been determined. The most important resonant frequencies, modes, and compliances are reported. Their consequences with regard to the surface quality of diamond turned parts are discussed. (IPT)