PARAMETRIC INTERPOLATOR VERSUS LINEAR INTERPOLATOR FOR PRECISION CNC MACHINING

The paper presents a comparative study of linear and parametric interpolators used for command generation during CNC machining. For many decades, linear interpolators have been used in NC machines for command generation. 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 interpolator are introduced. The comparison is mainly based on memory size, feedrate fluctuation and CPU time. Other considerations include tracking errors and jerk magnitude. Results show that the parametric interpolator is favourable in the machining of free-form geometry in terms of high speed and tight tolerancing.