## 1 Introduction
Analogously to the previously mentioned papers, this paper presents a methodology focused on the evaluation of the effects of CNC interpolator settings on output quality and precision by formulating prediction models based on data obtained on a training toolpath and verifying the results on a verification toolpath. Unlike the above-mentioned paper, however, the presented method focuses on a specific commercial interpolator (namely, the iTNC530 by Heidenhain) and the effects of its parameter settings on toolpath quality and precision in corner neighborhoods without considering the effects of NC data quality, servo loop control, and machine dynamics. To this end, a novel method of estimating the quality of the toolpath in corner neighborhoods is introduced. This method primarily focuses on the variation in contour error as a function of the toolpath arclength. The overarching aim here is to use a simplified testing toolpath trajectory to model the dependence of quality and accuracy of the interpolator output on CNC parameter settings such as contour tolerance, limit frequency, and corner and axial jerk limits. As this model of interpolator behavior does not depend on the unique dynamical properties of the individual machine tool, it is applicable to any machine tool equipped with the same interpolator system. The presented results show that effective ranges exist for some of the investigated interpolator variables (most importantly, the corner jerk limits) that should be considered in the future design of CNC parameter optimization models that include the effects of the servo loop and machine dynamics. To summarize, the main novelty of the presented research lies in the focus on toolpath quality and precision of the output of a specific commercial interpolator (excluding the effects of servo loop control and machine dynamics), leading to predictive models that are directly applicable to a wide range of machine tools. A novel method of toolpath quality evaluation based on the variation in contour error with respect to toolpath arclength is presented to this end. This paper is organized as follows: The motivation for the research presented is presented at the beginning of Section 2. The general methodology is described in Section 2.1. The definitions of the test and validation toolpaths are given in Sections 2.2 and 2.3, respectively. The contour error evaluation method is presented in Section 2.4 and the toolpath quality evaluation method is presented in Section 2.5. The interpolator parameters included in the test and their tested values are described in Section 2.6. Section 2.7 describes the data processing methods, while Section 2.8 includes details about experimental verification. Section 3 focuses on the interpretation of the test results. The dependence of toolpath quality in corner neighborhoods on interpolator parameter settings is described in Section 3.1. Section 3.2 describes the dependence of maximal contour errors in corner neighborhoods on the interpolator parameter settings. The discussion of the results presented, along with possible directions for future research, is presented in Section 4. The paper is concluded with Appendix A, in which the parameters of the presented regression models are given.