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+--- Thread: A gun drill mechanics model analysis (/showthread.php?tid=1341)
A gun drill mechanics model analysis - koipdd64 - 03-02-2022
Gun drilling is a process used to produce small-diameter holes at a high depth-to-diameter ratio, beyond what is capable using conventional tooling, especially for difficult-to-machine superalloys such as titanium, Inconel, Monel, etc. Presently, it often incapacitates by low productivity, rapid tool wear, frequent tool breakages, and straightness deviation. This chapter addresses the challenges of tackling these problems by employing game-changing approaches and technologies. Existing research in the advanced gun drilling technologies tends to focus on the choice of drilling parameters. There is little literature available for the cutting mechanics and workpiece deformation, tool geometry, wear and failure mechanism, especially in the deep hole drilling process for superalloys. Consequently, the aim of this chapter is to provide an overview of how the game-changing approaches and technologies for advanced gun drill tool can be explored and utilized.
The drilling of deep holes by means of deep hole gun drill is investigated so as to establish the parameters of the guide hole and its production. The rate of change in the load on the tool is proportional to the active length of the primary cutting edge. Assessment of the smoothness of tool insertion on the basis of the rate of change in the load on the tool is proposed.
Drilling mechanics model has always been the key and difficult point in the research field of solid carbide gun drill. In this paper, through theoretical analysis and processing experiments, the gun drilling mechanics model of Ti6Al4V titanium alloy is studied. On the one hand, based on the Oxley cutting model and the Johnson-Cook flow stress model, this paper takes Ti6Al4V titanium alloy as the research object and use the “microelement” method to establish the mechanical model of gun drilling, which includes cutting parameters, tool geometric parameters and material mechanical properties. On the other hand, the drilling model considers the influence of process damping and verified by experiments. The results show the calculated value of the model is consistent with the experimental value and the error is within the acceptable range. The model provides a theoretical basis for the prediction of drilling force, tool analysis and straightness error analysis.
this insert gun drill is considered as flexible continuous beam loaded with eccentrically applied cutting force. The new approach allows considering the influence of lateral vibrations on the dynamics of the gun drilling system. The multiple scale method is applied for nonlinear vibrations analysis. Stability diagram was constructed and bifurcation diagrams were obtained by multi-scale expansion. The nonlinear behavior of system in vicinity of stability borders was analyzed by using numerical integration of nonlinear equation.