CN111168134A

CN111168134A - A kind of milling cutter and design method

Info

Publication number: CN111168134A
Application number: CN202010114418.0A
Authority: CN
Inventors: 盛冬平; 李晓贞; 徐红丽; 门艳钟; 何亚峰
Original assignee: Changzhou Institute of Technology
Current assignee: Changzhou Institute of Technology
Priority date: 2020-02-25
Filing date: 2020-02-25
Publication date: 2020-05-19
Anticipated expiration: 2040-02-25
Also published as: CN111168134B

Abstract

The invention provides a milling cutter and a design method. The milling cutter comprises a damping alloy spline sleeve, a cutter arbor and a cutter head assembly, and the damping alloy spline sleeve and the cutter arbor adopt the installation method of interference fit to realize the transmission of force. The damping alloy spline sleeve is installed on the outermost layer of the cutter rod, and the deformation amount of the damping alloy spline sleeve and the cutter rod gradually decreases from the outer side to the center position, until zero; milling cutter design method It includes the following steps: obtaining the original three-dimensional design model of the milling cutter, designing the damping alloy spline sleeve, and determining the variable interval of each parameter; obtaining the torsional stiffness matrix of the milling cutter under the combined variables through finite element analysis, and in each Structural damping ratio matrix at stiffness value; input vibration resistance value parameter

The optimal design scheme of the milling cutter is determined, which solves the problem that the milling cutter is prone to violent vibration during the milling process and is likely to cause serious damage to the milling machine system.

Description

Milling cutter and design method

Technical Field

The invention relates to the technical field of machine tool machining, in particular to a deep hole vibration reduction milling cutter and a design method thereof.

Background

The milling cutter is a cutter commonly used in machine tool machining, is mainly used for washing and cutting plane and hole features, and structurally mainly comprises a cutter bar and a cutter head assembly, wherein in the milling process, due to the existence of milling force, milling force acts on a workpiece and also acts on the milling cutter in a reaction mode, and due to the fact that the direction of the milling force is circumferential, the load acting on the cutter in the reaction mode is a torque, the acting force and the reaction force can cause the milling cutter and the workpiece to vibrate in the milling process, and in the more serious case, the cutter vibrates, so that a milling machine system can directly generate severe vibration and strong noise, and the workpiece and the milling cutter can be seriously influenced.

In order to solve the vibration problem, two schemes are provided, wherein the first scheme is to add damping materials in the tool bit assembly so as to achieve the purpose of increasing the damping of the system structure, and the scheme obviously reduces the rigidity of the tool bit while increasing the damping, so that the tool bit is only suitable for the local parameter range of low-speed and small cutting amount in practical application; the second scheme is that a tuning vibrator is added in the cutter bar, and the vibration of the milling cutter is transferred to the tuning vibrator in the guide rod, so that the vibration reduction of the cutter head assembly is realized.

Disclosure of Invention

The milling cutter and the design method provided by the invention solve the problems that the milling cutter is easy to generate severe vibration in the milling process and is easy to cause serious damage to a milling machine system, remarkably reduce the vibration of the milling cutter in the milling process and improve the processing quality.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

the invention discloses a milling cutter which comprises a damping alloy spline housing, a cutter rod and a cutter head assembly, wherein force transmission is realized between the damping alloy spline housing and the cutter rod in an interference fit installation mode, the damping alloy spline housing is installed on the outermost layer of the cutter rod, and the deformation of the damping alloy spline housing and the deformation of the cutter rod are gradually reduced from the outside to the center until the deformation is zero.

Further, the damping alloy spline housing is made of a high manganese-based damping alloy material.

Further, the damping alloy spline housing outer diameter needs to be equal to the outer diameter dimension of the original milling cutter.

The invention also discloses a design method of the milling cutter, which comprises the following steps:

obtaining an original three-dimensional design model of the milling cutter, designing a damping alloy spline housing 1, establishing key design parameters including a spline major diameter A, a spline minor diameter B, a spline width C, a spline housing length L and the number N of internal splines, determining a variable interval of each parameter, and expressing the variable interval by using a matrix as follows:

obtaining a torsional rigidity matrix [ K ] of the milling cutter under the combined variable by taking key design parameters of a spline major diameter A, a spline minor diameter B, a spline width C, a spline housing length L and the number N of internal splines as variables through finite element analysis_t]And a matrix [ ζ ] of the damping ratio of the structure at each stiffness value]；

Introducing a vibration resistance value parameter theta which is equal to the product of the rigidity matrix and the damping ratio matrix and is expressed by the following formula:

[θ]＝[k_t][ζ]；

wherein [ theta ]]Is a matrix of vibration resistance values, [ k ]_t]Is a torsional stiffness matrix, [ zeta ]]A structural damping ratio matrix;

determining the optimal design scheme of the milling cutter, and expressing the optimal design scheme by using a formula as follows:

θ_max(t,l)＝Max([k_t][ζ])；

wherein, [ k ]_t]Is a torsional stiffness matrix, [ zeta ]]A structural damping ratio matrix;

and (5) checking again through finite element analysis to complete the design.

The beneficial technical effects are as follows:

1. the invention discloses a milling cutter, which comprises a damping alloy spline sleeve, a cutter rod and a cutter head assembly, wherein the damping alloy spline sleeve and the cutter rod are arranged in an interference fit mode to realize force transmission, the damping alloy spline sleeve is arranged on the outermost layer of the cutter rod, the deformation of the damping alloy spline sleeve and the deformation of the cutter rod are gradually reduced from the outside to the center until the deformation is zero, the problems that the milling cutter is easy to generate severe vibration in the milling process and the milling machine system is easy to be seriously damaged are solved, the vibration of the milling cutter in the milling process is obviously reduced, and the processing quality is improved.

2. The invention discloses a method for designing a milling cutter, which comprises the following steps of obtaining an original three-dimensional design model of the milling cutter, designing a damping alloy spline housing, and determining a variable interval of each parameter; obtaining a torsional rigidity matrix of the milling cutter under the combined variable and a structural damping ratio matrix under each rigidity value through finite element analysis; and determining an optimal design scheme of the milling cutter according to the vibration resistance value parameter theta, carrying out parametric design on the damping alloy spline housing to obtain the rigidity and the structural damping ratio of the parameterized milling cutter, and obtaining optimal design parameters through an optimal design theory, so that the vibration and noise reduction performance of the milling cutter and the service life of the cutter are optimized.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments will be briefly described below.

Fig. 1 is an overall structural view of a milling cutter of the present invention;

FIG. 2 is an exploded view of a milling cutter according to the present invention;

FIG. 3 is an interface size view of a damping alloy spline housing of a milling cutter of the present invention;

the damping alloy spline housing comprises a 1-damping alloy spline housing, a 2-cutter bar and a 3-cutter head assembly.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The invention discloses a milling cutter, which comprises a damping alloy spline housing 1, a cutter bar 2 and a cutter head assembly 3, and preferably, the damping alloy spline housing 1 is made of a high manganese-based damping alloy material which has a damping coefficient similar to that of rubber and has strength similar to that of low-carbon steel, the outer diameter of the damping alloy spline housing 1 needs to be equal to the outer diameter of an original milling cutter, and if the original milling cutter is subjected to remanufacturing, the cutter bar of the original milling cutter needs to be subjected to secondary processing so as to be adapted to the assembly of the damping alloy spline housing 1.

As an embodiment of the invention, in order to facilitate processing and assembly, the damping alloy spline housing 1 and the cutter bar 2 are installed in an interference fit mode to realize force transmission, the damping alloy spline housing 1 is installed on the outermost layer of the cutter bar 2, the deformation of the damping alloy spline housing 1 and the cutter bar 2 is gradually reduced from large to zero from outside to center, namely the contribution of an outside material to deformation resistance is maximum, the generated damping effect is also highest, the problems that a milling cutter is easy to generate severe vibration in the milling process and the milling cutter system is easy to be seriously damaged are solved, the vibration of the milling cutter in the milling process is obviously reduced, and the processing quality is improved.

The invention discloses a milling cutter design method on the other hand, which comprises the following steps:

wherein, A is the major diameter of spline, and B is the spline path, and C is the spline width, and L is spline housing length, and N is the internal spline number.

Because the body material of the conventional milling cutter is 40Cr, and the elastic modulus E of the conventional milling cutter is greater than that of the high manganese-based damping alloy, a certain relation exists between the rigidity and the damping ratio of the vibration reduction milling cutter, namely the rigidity is increased, and the damping ratio is reduced; the stiffness decreases and the damping ratio increases. And the machining characteristics of the vibration reduction milling cutter are determined by the rigidity and the damping ratio.

Based on the above analysis, there is a certain variation relationship between the bending stiffness and the damping ratio, so the torsional stiffness matrix [ k ]_t]And damping matrix [ zeta ]]Product matrix [ theta ] of]There exists a maximum value, and the variation curve of the product value of the two has a peak inflection point.

Introducing a vibration resistance value parameter theta which is equal to the product of the torsional rigidity matrix and the damping ratio matrix and is expressed by the following formula:

[θ]＝[k_t][ζ]；

introducing a parameter vibration resistance value theta, carrying out parametric design on the damping alloy spline housing to obtain parameterized milling cutter rigidity and structural damping ratio, and obtaining optimal design parameters through an optimal design theory, so that the vibration and noise reduction performance and the cutter service life of the milling cutter are optimized, and the optimal design scheme of the milling cutter is determined and expressed by a formula as follows:

θ_max(t,l)＝Max([k_t][ζ])；

and (5) checking again through finite element analysis to complete the design.

The above examples are only for describing the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention, and various modifications and improvements made to the technical solution of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. a milling cutter, comprising a damping alloy spline sleeve 1, a cutter bar 2 and a cutter head assembly 3, it is characterized in that, between the damping alloy spline sleeve 1 and the cutter bar 2, the installation mode of interference fit is adopted to realize the force Transmission, the damping alloy spline sleeve 1 is installed on the outermost layer of the cutter bar 2, and the deformation amount of the damping alloy spline sleeve 1 and the cutter bar 2 gradually decreases from the outer side to the center position, until it is zero.

2 . The milling cutter according to claim 1 , wherein the damping alloy spline sleeve 1 is made of high manganese-based damping alloy material. 3 .

3 . The milling cutter according to claim 1 , wherein the outer diameter of the damping alloy spline sleeve 1 needs to be equal to the outer diameter of the original milling cutter. 4 .

4. the design method of a kind of milling cutter according to any one of claim 1-3, comprises the following steps:

Obtain the original 3D design model of the milling cutter, design the damping alloy spline sleeve 1, and establish the key design parameters spline major diameter A, spline minor diameter B, spline width C, spline sleeve length L and number N of internal splines, Determine the variable interval for each parameter, represented by a matrix as follows:

Through finite element analysis, the key design parameters spline major diameter A, spline minor diameter B, spline width C, spline sleeve length L and the number of internal splines N are used as variables to obtain the torsion of the milling cutter under this combination of variables. stiffness matrix [K _t ], and structural damping ratio matrix [ζ] at each stiffness value;

The vibration resistance parameter θ is introduced, which is equal to the product of the stiffness matrix and the damping ratio matrix, which is expressed as follows:

[θ]=[k _t ][ζ];

Among them, [θ] is the vibration resistance value matrix, [k _t ] is the torsional stiffness matrix, and [ζ] is the structural damping ratio matrix;

Determine the optimal design scheme of the milling cutter, which is expressed by the formula as follows:

θ _max (t,l)=Max([k _t ][ζ]);

where [k _t ] is the torsional stiffness matrix, and [ζ] is the structural damping ratio matrix;

The design is completed after rechecking through finite element analysis.