Full factorial models of dimensional accuracy of multi-tool machining on automatic turning machines

The paper presents the current development of the design theory of multi-tool machining on automatic turning machines. The existing processing error models take into account only plane-parallel displacements of subsystems of the technological system along the coordinate axes in the Cartesian coordinate system X, Y, Z. This approach to modeling the formation of machining errors is valid for the parts that have equal-order dimensions in all coordinate directions. However, there are cases of machining parts with significantly different dimensions. In these cases, a significant contribution to the machining error can be made by turning the workpiece, especially in the directions of the prevailing dimensions. Therefore, these models have to take into account the angular movements of the workpiece exposed to the cutting forces. To this end, we developed a full factorial matrix model of distortion and dissipation field of multi-tool dual-carriage dimensioning. These models take into account a complex characteristic of compliance of the technological system, i.e., apart from the elastic properties (plane-parallel displacements of technological subsystems, their angular displacements around the base points), they also take into account the setup parameters for which its ductility is considered. Therefore, to form a complex characteristic of the subsystem ductility, we conducted experiments to determine the ductility of the subsystem in the technological system. Actual matrix characteristics of ductility for a real machine make it possible to evaluate the practical applicability of the developed full-factorial matrix models of machining accuracy. As a result, it can allow us to identify the degree of influence on the machining accuracy of a complex of technological factors, including the structure of multi-tool set-up, deformation properties of the subsystems in the technological system, and cutting modes.