Design And Study Of Plunge Milling Cutters With Unequal Pitch

As a clean and renewable energy,hydropower has attracted national attention,the core component of which is a cavity-hydraulic turbine.Thus the milling cutter must have certain overhang length.The process of plunge milling in the state of long hanging will cause severe vibration of the machining,increase the cutting force and shorten the life of the tool.In order to improve the milling stability of the process of plunge milling,the concept of unequal pitch is introduced.The process of plunge milling with unequal pitch is studied in this paper: First,the force model of plunge milling cutter with unequal pitch is established.Then the milling force coefficient of each direction is obtained through test and analysis.And the coefficient function relation of milling force related to the per rotation feed is established.Moreover,the simulated milling force is calculated by MATLAB,and is compared with the actual test data,which can verify the reliability of the milling force model.Second,the materials of the body and the blade of the milling cutter are selected,and the shape of its body is designed.Through the frequency domain analysis,the distance angle of the plunge milling cutters with unequal pitch is optimized by using the least square sum of the deviation as the target function and the Monte Carlo method.Third,on the basis of the dynamic model of three degree of freedom and the instantaneous cutting thickness model,the dynamic equation of the plunge milling cutters with unequal pitch is established.The relevant parameters of the system are obtained by the hammer system of the force hammer;and the semi discrete method is used to solve the stable domain.Then the reliability of the stable domain is verified by experiments.In addition,the influence of the tool cutting edgeangle of the cutter and the amount of the suspension on the stable region is also analyzed.Finally,The resonance frequency and deformation amount of the plunge milling cutters with unequal pitch and equal pitch are studied by employing the modal analysis and statics analysis with the ANSYS.Under the same milling parameters,two milling cutters are used to carry out the milling test,and analyze the milling performance.In this paper,the design of the plunge milling cutter with unequal pitch and the analysis of its stability are mainly discussed to provide theoretical basis for ensuring the stability in the machining process of the cavity.