The Study On Chatter Stability Cr13 Plunge Milling Process

Plunge Milling is a new kind of machining method and widely used in aerospace, hydropower and mould manufacturing industries because of the characteristics of the material removal rate is high and the machining process stability is good. The material of bucket for the impulse turbine is C r13 stainless steel. And the length to diameter ratio for handle of the plunge milling processing is 14.9:1.The chatter is always happen during the process of flow channel rough machining and this will reduce the quality of the machined surface. The blade is easy to breakage especially during large margin processing and it seriously restricting the processing efficiency. Therefore, plunging stability following research is finished to obtain stable cutting process scheme to meet the curved surface plunge milling process efficient.The study establishes the milling force model for the plunge milling which is based on the theory rigid force without considering the vibration. This article obtains the infinitesima l cutting forces by dispersing the end blade into infinitesimal and superimposing its milling force in all directions which be deal with coordinate transformation. And then, it establishes milling force coefficient identification model for plunge milling and identifies the milling force coefficient of C r13 stainless steel plunge milling. The simulation program is used to predict the milling force and then to compare with experimental results in order to verify the accuracy of the coefficient which obtained by the model.The three degrees of freedom d ynamics model and milling thickness model which considering the effect of regeneration are established for plunge milling.Done experimental modal analys is for large ratio plunge milling system a nd use modal ansys software to identify modal parameters of plunge milling sys temOn the other hand, the time domain simulation of plunge milling provides theoretical support and parameters support.The study solves three degrees of freedom dynamics model by using the semi-discrete method to give the corresponding plunge milling Flutter Stability Region forecast map. The simulation explored the effect of plunging milling dynamic characteristics(natural frequency, damping ratio and stiffness) on the region of stability. The results show that improving plunge milling system natural frequency, damping ratio and stiffness can improve plunge milling process stability. But the impacts of stability are different.The large aspect ratio C r13 stainless steel plunging flutter stability is studied by the experiments. Plunge milling flutter stability curve which taken the maximum Lyapunov index as threshold is drawn. And it is compared with the semi-discrete method. All of these are used to the further study of plunge milling stability.This study can implement C r13 stainless steel plunging t ime domain simulation prediction and help optimizing large aspect ratio under C r13 stainless steel insert milling parameters. The milling stability study in this paper also has some significance.