The machining of any surfaces (planes, slots, holes, and so on) on the CNC machines of the drilling-milling-reaming group requires the preliminary alignment of the workpiece with its dimensional tie-in to the machine coordinate system and the subsequent displacements of the machine's actuators in accordance with the commands of the control program (CP). In this process the cutting tool (CT) displaces toward the workpiece surface along the coordinate axes at the no-load velocity, while the machining of the surfaces is performed at the working feed velocity. With account for the foregoing, when analyzing the assurance of the accuracy of machining on the CNC machines, we need to identify two stages: the stage of the alignment of the machine, and the stage of the machining process (machining as such). Then we need to approach the modeling of the machining accuracy as a combination of the characteristics of the achieving of the accuracy in these stages and perform the modeling for each stage individually [1]. Many parts that are machined on the CNC machines have holes with high requirements on their accuracy, including the accuracy of the location of their axes. The specified requirements relating to the positioning of the axes of the holes are not always met in production conditions; defective or deviant parts sometimes appear.
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