Automatic processing cycles of CNC grinding machine control systems: analysis and classification using the example of Siemens Sinumerik 802D sl

Modern mechanical engineering imposes increased requirements on the accuracy, surface quality, and productivity of finishing processes, among which grinding holds a key position. The enhancement of stability and efficiency in grinding operations is achieved through the use of Computer Numerical Control (CNC) machines equipped with automatic cycle systems. However, insufficient systematization of knowledge about the built-in cycles of modern CNC systems complicates their justified selection and effective application in production process planning. The aim of this research is the analysis and classification of the built-in automatic cycles of the Siemens Sinumerik 802D sl CNC system, focused on grinding operations, to assess their functional purpose and areas of rational application. The methodological basis of the work was a systematic analysis of the technical and reference documentation for this specific CNC system, as well as a review of scientific publications in the field of grinding technology. As a result of the study, a classification of automatic cycles was developed, structured by purpose into three groups: workpiece surface machining cycles, grinding wheel dressing and profiling cycles, and auxiliary cycles. A detailed analysis of the most technologically significant group – the machining cycles (CYCLE405, CYCLE410, CYCLE411, CYCLE412, CYCLE413, CYCLE414, CYCLE415, CYCLE451) – was conducted. Their clear specialization by the type of geometry being processed (short and long cylindrical surfaces, conical surfaces, faces, radii) and the applied grinding methods (with longitudinal feed, plunge, multi-pass, with oscillation) has been established. It was revealed that a key advantage of these cycles is the implementation of the classic three-stage processing scheme (roughing, finishing, spark-out), which minimizes the influence of elastic deformations and thermal effects and allows for the independent assignment of cutting conditions for each stage. The results of the work make it possible to formalize the process of selecting the optimal automatic cycle based on the part geometry, required surface quality, and characteristics of the grinding tool, thereby reducing process planning time and minimizing the influence of the subjective human factor.