Fe-modeling of tapping for calculating the virtual pitch thread diameter

The development of high-precision tapping operations involves predicting such accuracy. Very often, this requires expensive experiments. Numerical calculation methods, which have recently received wide application, make it possible to replace these experiments with computer simulations. However, this modeling is now mainly associated with determining the stresses and strength of tools, for which only the cutting tool itself and a fragment of the workpiece are modeled. This approach turns out to be unacceptable for predicting the machining accuracy, since the errors in the thread size and shape significantly depend on the actual movement of the tool, which, in turn, depends on the conditions of its fixing in the machine spindle. In this regard, the task concerns with not only the specified above technological system elements, but also an clamping tool. In addition, after calculating the thread surface of the part, it is necessary to calculate accuracy characteristics of this thread. It is these issues that are considered in this article: the results of finite element modeling of threading with a tap fixed in a tapping chuck of a floating-oscillating type are shown. The obtained graphs of axial force and torque correspond to the expected curves, both in its shape and in numerical values. The obtained thread point cloud made it possible to further calculate its virtual pith thread diameter, which turned out to be comparable with the corresponding tap diameter and the same thread size from the state standard. Thus, the above calculations show their realism and the possibility of application in the practice of designing thread-cutting operations.