Study on Vibration Properties of Solid Carbide Helical End Mill with Small Diameter
|Keywords||end mill bending vibration milling simulation|
With characteristics of light mass, high strength and good dynamic performance, the thin-walled monolithic construction components have been widely used in the aviation industry, but they yield deformation very easily. High-speed milling can relieve distortion and high-speed machining demands that end mills possess high comprehensive performance. In this dissertation, theoretical analysis and numerical simulations were adopted to discuss the vibration characteristics of small diameter end mills with two, three and four flutes. The contents of main work in this thesis are summarized as follows:According to the principle of grinding mills, the theoretical model of helical surface was created and the rake angle of an end mill was computed. Based on3D modeling software UG, three-dimensional solid models of end mills with two, three and four flutes were constructed, and cutters’modal analyses and static analyses were conducted, and the equivalent stiffness coefficients of mills were also computed; a3D solid model of simplified thin-walled aviation part was also created, and the workpiece modes were solved to study its law of distortion.The mills were simplified as Euler-Bernoulli slender straight cantilevers, and their theoretical models of bending vibration were constructed in one plane containing the axis of mill; the vibration response of cutter under the load with any law was also studied and established. Applying approximate methods, the mills were regarded as discrete systems with limited degrees of freedom; this thesis obtained equivalent mass matrix, equivalent stiffness, and flexibility influence coefficient matrix, and established undamped free vibration equation and gained the first two modal frequencies.With the help of metal cutting software AdvantEdge FEM5.9, this dissertation conducted3D simulations of milling aluminum alloy7050-T7451with solid carbide end mills, and analyzed amplitude-frequency characteristics and statistical properties of the milling forces, and revealed that the milling force is random excitation with narrow band.Transient analyses of mills were executed on the basis of software UG, and received the displacement response curves of the free end of mills, and the statistical properties between the transient milling forces and displacements from a statistical point of view were studied; and by transient analysis this dissertation uncovered that the maximum displacements are power function for different clamping lengths of one mill.