Features of developing the mathematical model of metal removal for the digital twin of process of circular grinding with CNC

In conditions of the automated mechanical engineering the task of designing optimal cutting cycles for operations performed on CNC machines still remains unsolved. In practice, the technologist still has to manually adjust designed cycles using various CAD/CAM-systems, which have an information base based on the data from the normative reference literature developed in the 60-90`s for universal equipment. At that the technologist relies on personal experience or on the existing data in similar operations. As a result, the cycles designed in this way cannot guarantee maximum productivity and durability of the equipment used, stability of accuracy and quality indicators in a batch of parts and, accordingly, the minimum cost price of the operation performed. As a solution to the problem described above, development of the digital twin on the example of a circular grinding operation is proposed. Analytical model of the layer-by-layer metal removal from the workpiece can be the digital twin of the circular grinding process. In addition to the initial processing conditions (main parameters of the workpiece, tool, equipment, tooling, etc.) which have a direct impact on the grinding process, this model must consider kinematics and features of the metal removal inherent in various types of grinding. Digital twin must consider instability of the grinding process (blunting of the wheel, allowance fluctuations, loss of the wheel diameter and, accordingly, the contact area of the wheel with the workpiece). The article describes the main stages of developing the analytical model of metal removal on the example of the circular grinding with longitudinal feed. The developed digital twin of the circular grinding operation can be used not only for designing optimal cycles of the cutting modes, but also for predicting the reliability of the developed cycles and the quality of processing in unstable conditions of processing the batch of parts.