Experimental and Analytical Investigation of Self-Excited Chatter Vibrations in Metal Cutting

1978 ◽  
Vol 100 (1) ◽  
pp. 92-99
Author(s):  
N. Saravanja-Fabris ◽  
A. F. D’Souza
Keyword(s):  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Analytical Investigation ◽  
Point Of View ◽  
Cutting Process ◽  
Describing Function ◽  
Describing Functions ◽  
Machine Tool Structure ◽  
Excited Vibration ◽  
The Stability

Chatter in metal cutting is a nonlinear self-excited vibration of the limit cycle type. This investigation is concerned with the analysis of chatter from the viewpoint of the describing function. Vibrations with different frequencies and amplitudes were superimposed on the steady feed motion of the tool in orthogonal cutting in order to simulate chatter. The relationships between the oscillating cutting and thrust forces and tool vibrations are discussed from the point of view of energy transfer and describing functions. Experimentally obtained describing functions of the dynamically varying cutting process are given. The stability of a typical machine tool structure under primary chatter conditions with dynamical cutting process represented by its describing function is discussed.

An Analysis and Modeling of the Dynamic Stability of the Cutting Process Against Self-Excited Vibration

2020 ◽  
Vol 22 (4) ◽  
pp. 1287-1300
Author(s):  
A. Motallebia ◽  
A. Doniavi ◽  
Y. Sahebi
Keyword(s):  
Machine Tool ◽  
Removal Rate ◽  
Dimensional Accuracy ◽  
Modal Testing ◽  
Cutting Process ◽  
Work Piece ◽  
Stability Diagrams ◽  
Machine Tool Structure ◽  
Excited Vibration ◽  
The Stability

AbstractChatter is a self-excited vibration which depends on several parameters such as the dynamic characteristics of the machine tool structure, the material of the work piece, the material removal rate, and the geometry of tools. Chatter has an undesirable effect on dimensional accuracy, smoothness of the work piece surface, and the lifetime of tools and the machine tool. Thus, it is useful to understand this phenomenon in order to improve the economic aspect of machining. In the present article, first the theoretical study and mathematical modeling of chatter in the cutting process were carried out, and then by performing modal testing on a milling machine and drawing chatter stability diagrams, we determined the stability regions of the machine tool operation and recognized that witch parameter has a most important effect on chatter.

Analysis of Oblique Cutting Forces

1967 ◽  
Vol 89 (2) ◽  
pp. 347-355 ◽  
Author(s):  
Russell F. Henke
Keyword(s):  
Steady State ◽  
Cutting Force ◽  
Cutting Forces ◽  
Metal Cutting ◽  
Single Point ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Chip Area ◽  
Oblique Cutting ◽  
The Stability

This paper is the latest of a continuing series on the subject of self-excited machine tool chatter. The representation of the metal cutting process as required by the previously developed closed-loop chatter theory is extended to oblique cutting with tools of practical shape and geometry. The cutting process parameters essential to proper application of the stability theory are found by an analytical formulation leading to a classical eigenvalue problem. Techniques are developed to determine the steady-state constant of proportionality between resultant cutting force and uncut chip area, the direction of resultant cutting force, and the direction of maximum cutting stiffness for any single-point cutting operation. In the process, a general method to predict steady-state oblique cutting forces is evolved. The method depends on certain experimentally justifiable assumptions and utilizes previously compiled orthogonal cutting data.

scholarly journals An Analysis and Modeling of the Dynamic Stability of the Cutting Process Against Self-Excited Vibration

2019 ◽  
Vol 23 (1) ◽  
pp. 28-35
Author(s):  
A. Motallebia ◽  
A. Doniavi ◽  
Y. Sahebi
Keyword(s):  
Machine Tool ◽  
Removal Rate ◽  
Dimensional Accuracy ◽  
Modal Testing ◽  
Cutting Process ◽  
Work Piece ◽  
Stability Diagrams ◽  
Machine Tool Structure ◽  
Excited Vibration ◽  
The Stability

Abstract Chatter is a self-excited vibration that depends on several parameters such as the dynamic characteristics of a machine tool structure, the material of work piece, the material removal rate, and the geometry of tools. Chatter has an undesirable effect on dimensional accuracy, smoothness of work piece surface, lifetime of tools and machine tools. Thus, it is useful to understand this phenomenon in order to improve the economic aspect of machining. In the present article, firstly, the theoretical study and mathematical modeling of chatter in the cutting process were carried out. Then, by performing modal testing on a milling machine and drawing chatter stability diagrams, we determined the stability regions of the machine tool operation and recognized the parameter that had the most important effect on chatter.

Study on Self-Excited Vibration Mechanism of Wheel-Rail Lateral Contact System

2013 ◽  
Vol 427-429 ◽  
pp. 257-261
Author(s):  
Li Xia Sun ◽  
Jian Wei Yao ◽  
Fu Guo Hou ◽  
Xin Zhao
Keyword(s):  
Feedback Mechanism ◽  
Point Of View ◽  
Contact System ◽  
Vibration System ◽  
Lateral Contact ◽  
System A ◽  
Vibration Model ◽  
Excited Vibration ◽  
Vibration Mechanism ◽  
The Stability

In order to investigate self-excited vibration mechanism of wheel-rail lateral contact system, a two DOF elasticity position wheelset lateral vibration model is established which considers the dry friction; the mechanism of the wheelset lateral self-excited vibration is investigated from the energy point of view. It shows that: the bifurcation diagram of this wheel-rail lateral contact system has a supercritical Hopf bifurcation. The energy of self-excited vibration derives from a part of traction energy; the creep rate in the wheel-rail system act as a feedback mechanism in the wheelset lateral self-excited vibration system. The stability of the wheelset self-excited vibration system depends mainly on the total energy removed from and imported into the system.

Determination of Inner and Outer Modulation Dynamics in Orthogonal Cutting

1987 ◽  
Vol 109 (4) ◽  
pp. 275-280 ◽  
Author(s):  
T. Y. Ahn ◽  
K. F. Eman ◽  
S. M. Wu
Keyword(s):  
Orthogonal Cutting ◽  
Theoretical Background ◽  
Cutting Process ◽  
Experimental Realization ◽  
Process Dynamics ◽  
Orthogonal Turning ◽  
Machine Tool Structure ◽  
Dynamic Cutting Force ◽  
Experimental Errors ◽  
Modeling Strategy

Many efforts have been devoted in the past to the identification of the dynamic behavior of the cutting process. Nevertheless, there have been no consistent results due to the inherent complexity of the cutting process, and the methodological and experimental errors involved. Among the problems to be solved, the experimental realization of the double modulation is the most difficult one. Present approaches use elaborate instrumentation and assume the delayed inner modulation for the outer modulation. This assumption may not hold under all circumstances and it will be modified in this paper. The present method approaches the cutting process as a one-input one-output process consisting of the inner modulation and dynamic cutting force component. The application of bivariate time series models give the transfer function of the inner modulation dynamics. The outer modulation dynamics’ effect on the cutting process is subsequently determined from the disturbance noise dynamics. The theoretical background for the proposed approach along with a new modeling strategy has been introduced in detail. The experimental verification of the theoretical postulates and the identification of the cutting process dynamics were carried out using actual data collected from an orthogonal turning process of a tubular workpiece. External white noise excitation was used and the experimental setup was designed to minimize the errors caused by inertia and disturbances. Although the proposed method requires prior knowledge of the machine tool structure, it requires a comparatively simple experimental procedure and minimizes the possible errors associated with the signal processing task.

Numerical Simulation of Metal Cutting Process Based on ANSYS/LS-DYNA

2015 ◽  
Vol 727-728 ◽  
pp. 335-338 ◽  
Author(s):  
Song Jie Yu ◽  
Di Di Wang ◽  
Xin Chen
Keyword(s):  
Cutting Force ◽  
Metal Cutting ◽  
Plastic Material ◽  
Orthogonal Cutting ◽  
Cutting Process ◽  
Machining Process ◽  
Linear Deformation ◽  
Deformation Problem ◽  
Non Linear ◽  
Elastic Plastic Material

Cutting process is a typical non-linear deformation problem, which involves material non-linear, geometry non-linear and the state non-linear problem. Based on the elastic-plastic material deformation theory, this theme established a strain hardening model. Build the simulation model of two-dimensional orthogonal cutting process of workpiece and tool by the finite element method (FEM), and simulate the changes of cutting force and the process of chip formation in the machining process, and analyzed the cutting force, the situation of chip deformation. The method is more efficient and effective than the traditional one, and provides a new way for metal cutting theory, research of material cutting performance and cutting tool product development.

Basic Mechanics of the Metal-Cutting Process

1944 ◽  
Vol 11 (3) ◽  
pp. A168-A175 ◽  
Author(s):  
M. Eugene Merchant
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Orthogonal Cutting ◽  
Cutting Edge ◽  
Cutting Process ◽  
Work Piece ◽  
Machining Operations ◽  
Work Done ◽  
Metal Work

Abstract The author presents a mathematical analysis of the geometry and mechanics of the metal-cutting process, covering two common types of geometry which occur in cutting. This analysis offers a key for the study of engineering problems in the field of metal cutting in terms of such fundamental quantities as strain, rate of shear, friction between chip and tool, shear strength of the metal, work done in shearing the metal and in overcoming friction, etc. The two cases covered are, in essence, that of a straight-edged cutting tool moving relative to the work-piece in a direction perpendicular to its cutting edge, termed “orthogonal cutting,” and that of a similar cutting tool so set that the cutting edge is oblique to the direction of relative motion of tool and work, termed “oblique cutting.” Equations are developed which permit the calculation of such quantities as those just enumerated from readily observable values. The theoretical findings are particularly applicable and significant in the case of present-day high-speed machining operations with sintered-carbide tools.

scholarly journals Estimates of the bistable region in metal cutting

2008 ◽  
Vol 464 (2100) ◽  
pp. 3255-3271 ◽  
Author(s):  
Zoltan Dombovari ◽  
R. Eddie Wilson ◽  
Gabor Stepan
Keyword(s):  
Cutting Force ◽  
Metal Cutting ◽  
Classical Model ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Stability Limit ◽  
Force Characteristic ◽  
Inflexion Point ◽  
The Stability ◽  
Force Characteristics

The classical model of regenerative vibration is investigated with new kinds of nonlinear cutting force characteristics. The standard nonlinear characteristics are subjected to a critical review from the nonlinear dynamics viewpoint based on the experimental results available in the literature. The proposed nonlinear model includes finite derivatives at zero chip thickness and has an essential inflexion point. In the case of the one degree-of-freedom model of orthogonal cutting, the existence of unstable self-excited vibrations is proven along the stability limits, which is strongly related to the force characteristic at its inflexion point. An analytical estimate is given for a certain area below the stability limit where stable stationary cutting and a chaotic attractor coexist. It is shown how this domain of bistability depends on the theoretical chip thickness. The comparison of these results with the experimental observations and also with the subcritical Hopf bifurcation results obtained for standard nonlinear cutting force characteristics provides relevant information on the nature of the cutting force nonlinearity.

Effects of Strain Rate and Temperature in Orthogonal Metal Cutting

1966 ◽  
Vol 8 (3) ◽  
pp. 264-275 ◽  
Author(s):  
G. Boothroyd ◽  
J. A. Bailey
Keyword(s):  
Theoretical Analysis ◽  
Strain Rate ◽  
Metal Cutting ◽  
Single Phase ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Rake Angle ◽  
Cutting Process ◽  
Strain Rates ◽  
Continuous Chip

A new theoretical analysis of the orthogonal cutting process is described which is based on the known behaviour of a single phase metal at high strains, strain rates and temperatures. The theoretical analysis applies to the case where a continuous chip is produced under non-lubricated conditions with the absence of a built-up edge on the tool face and indicates the important parameters in the cutting process. The theory is examined experimentally and its validity established. Finally, from a knowledge of the effects of strain rate and temperature on the yield stress of a single phase metal, the theory is used to predict the effects of changes in cutting speed and tool rake angle on the tool forces and geometry of the cutting process. These predictions are compared qualitatively with the results of cutting tests.

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