PARAMETRIC INTERPOLATOR VERSUS LINEAR INTERPOLATOR FOR PRECISION CNC MACHINING

The paper presents a comparative study of linear and parametric interp olators used for command generation during CNC machining. For many dec ades, linear interpolators have been used in NC machines for command g eneration. Recently, a parametric interpolator has been developed that is designed for command generation for parametric curves (or surfaces ). Two algorithms for the online implementation of this parametric int erpolator are introduced. The comparison is mainly based on memory siz e, feedrate fluctuation and CPU time. Other considerations include tra cking errors and jerk magnitude. Results show that the parametric inte rpolator is favourable in the machining of free-form geometry in terms of high speed and tight tolerancing.