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Rapid acquisition method of workpiece dynamics parameters in milling process

A technology of kinetic parameters and acquisition methods, applied in program control, instrument, computer control, etc., can solve the problems of complicated process, large amount of calculation, poor generality, etc., and achieve the effect of improving computing efficiency and saving computing time.

Active Publication Date: 2018-11-02
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The above literatures all acquire the time-varying dynamic parameters of the workpiece during the milling process; however, in the actual operation process, the method disclosed in Literature 1 has a large amount of calculation, consumes a lot of time, and has relatively low calculation efficiency
The method disclosed in Document 1 requires a large number of modal percussion experiments, the process is cumbersome and complicated, and the versatility is relatively poor
This limits the rapid prediction of milling chatter during milling operations

Method used

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  • Rapid acquisition method of workpiece dynamics parameters in milling process
  • Rapid acquisition method of workpiece dynamics parameters in milling process
  • Rapid acquisition method of workpiece dynamics parameters in milling process

Examples

Experimental program
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Effect test

Embodiment 1

[0038] Example 1: The size of the thin plate is 102mm×36mm×4mm, the material is aluminum alloy 7075, the modulus of elasticity is 71GPa, and the density is 2810kg / m 3 , Poisson's ratio is 0.33.

[0039] 1. Aiming at the milling characteristics of thin-walled parts, establish a multi-point contact milling dynamics model that simultaneously considers the deformation of the tool and the workpiece; divide the contact area between the tool and the workpiece into 35 microelements along the axial direction, and divide the milling force of each unit Focus on nodes and find dynamic milling forces:

[0040]

[0041] The dynamic equation of the milling system is:

[0042]

[0043] m W,0,0 ,C W,0,0 , K W,0,0 Represents the mass, damping, and stiffness matrix of the initial workpiece; Q(t) represents the dynamic displacement of the workpiece in physical coordinates; transform the above formula from physical space to modal space to get:

[0044]

[0045] Γ w,0,0 (t) is the mo...

Embodiment 2

[0063] Example 2: The size of the curved thin plate is 104mm long, 35mm high, 3.5mm thick, and the radius of curvature is 297mm; the material is aluminum alloy 7075, the modulus of elasticity is 71GPa, and the density is 2810kg / m 3 , Poisson's ratio is 0.33.

[0064] 1. Aiming at the milling characteristics of thin-walled parts, establish a multi-point contact milling dynamics model that simultaneously considers the deformation of the tool and the workpiece; divide the contact area between the tool and the workpiece into 34 microelements along the axial direction, and divide the milling force of each unit Focus on nodes and find dynamic milling forces:

[0065]

[0066] The dynamic equation of the milling system is:

[0067]

[0068] m W,0,0 ,C W,0,0 , K W,0,0 Represents the mass, damping, and stiffness matrix of the initial workpiece; Q(t) represents the dynamic displacement of the workpiece in physical coordinates; transform the above formula from physical space to...

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Abstract

For acquisition of workpiece dynamics parameters and rapid prediction of milling chatter stability considering material removal and cutting tool position variation causing the variation of the workpiece dynamics parameters in the thin-walled workpiece milling process, the invention provides a method for acquiring time-varying dynamics parameters of a workpiece through degree-of-freedom reduction and matrix dimensionality reduction. The method comprises the steps of: utilizing a finite element to obtain quality and stiffness matrixes of the workpiece; reducing the dimensionality of the qualityand stiffness matrixes of the workpiece through carrying out degree-of-freedom reduction and matrix dimensionality reduction; and finally, acquiring dynamics parameters of the workpiece at different tool position points rapidly by adopting a numerical calculation method, and performing stability prediction.

Description

technical field [0001] The invention relates to a method for acquiring the natural frequency and modal formation of workpieces in the milling process, which is mainly applicable to the rapid prediction of the flutter stability domain in the whole milling process of thin-walled parts. Background technique [0002] Document 1 "Budak E, Tunc L.T., Alan S., et al. Prediction of workpiece dynamics and its effects on chatter stability in milling [J]. CIRP Annals-Manufacturing Technology, 2012, 61:339-342." discloses a Use the matrix inversion method of the dynamic parameter matrix of the frequency response function of the workpiece to calculate the dynamic parameters of the workpiece during processing; use the finite element method to obtain the mass matrix and stiffness matrix of the workpiece and extract the mass of the removed material The matrix and stiffness matrix are combined into the frequency response function of the initial workpiece to calculate the dynamic parameters o...

Claims

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Application Information

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IPC IPC(8): G05B19/408
CPCG05B19/4083G05B2219/35356
Inventor 万敏党学斌张卫红杨昀
Owner NORTHWESTERN POLYTECHNICAL UNIV
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