Main modeling stages of layer-by-layer metal removal with digital twin of the circular grinding operation with CNC

Modern circular grinding machines with CNC allow processing according to the specified cycles of cutting modes, which are part of a control program (CP). Despite the use of precise positioning systems, modern grinding machines have a compliance of a technological system (TS). This explains the fluctuations in a value of the allowance removal and occurrence of various errors in dimensions, which increase when processing a batch of parts performed in unstable conditions under the influence of a large number of variable technological factors (allowance fluctuation, blunting of the wheel grains, changes of the wheel diameter, etc.). However, in the presence of a large number of automated systems of CP designing there is still no tool for their control to ensure the processing accuracy of the parts batch. In addition, when designing cycles of the cutting modes the database obtained for universal machines is used in these systems. As a result, the designed cycles do not guarantee the stability of the accuracy indicators when processing a batch of parts, do not provide maximum productivity and require adaptation to the specified processing conditions. This article presents a description of the digital twin (DT) on the example of the plunge circular grinding, which allows simulating layer-by-layer metal removal during the whole grinding cycle by calculating the value of the removed allowance on each revolution of the workpiece under various combinations of unstable processing conditions and variable compliance of the technological system. Herewith, modeling of layer-by-layer allowance removal is performed in several sections which have different compliance. After the end of the metal removal modeling (at the end of the grinding cycle) it becomes possible to evaluate the accuracy by known calculated values of radii in all sections of the treated surface. It should be noted that the use of DT will speed up and simplify the process of cycles designing, as well as increase the productivity of CNC circular grinding operations by optimizing the cycles of cutting modes with ensuring the specified accuracy.