Identification of Process Damping Coefficient Based on Material Constitutive Property

2014 ◽  
Author(s):  
Xiaoliang Jin
Keyword(s):  
Energy Dissipation ◽  
Flank Wear ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Machining Process ◽  
Damping Coefficient ◽  
Chatter Stability ◽  
Workpiece Material ◽  
Process Damping ◽  
Constitutive Property

The contact between the tool flank wear land and wavy surface of workpiece causes energy dissipation which influences the tool vibration and chatter stability during a dynamic machining process. The process damping coefficient is affected by cutting conditions and constitutive property of workpiece material. This paper presents a finite element model of dynamic orthogonal cutting process with tool round edge and flank wear land. The process damping coefficient is identified based on the energy dissipation principle. The simulated results are experimentally validated.

Identification of Machining Process Damping Using Output-Only Modal Analysis

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
K. Ahmadi ◽  
Y. Altintas
Keyword(s):  
Orthogonal Cutting ◽  
Machining Process ◽  
Damping Coefficient ◽  
Chatter Stability ◽  
Force Coefficient ◽  
Workpiece Material ◽  
Process Damping ◽  
Indentation Force ◽  
Output Only ◽  
Cutting Speeds

The existing chatter stability prediction algorithms fail in low-speed machining of difficult to cut alloys, unless process damping contributed by the tool flank face–finish surface contact is considered. This paper presents a new method in predicting the material dependent process damping coefficient from chatter free orthogonal cutting tests. An equivalent process damping coefficient of the dynamic system is estimated from the frequency domain decomposition (FDD) of the vibration signals measured during stable cutting tests. Subsequently, the specific indentation force of the workpiece material is identified from the process damping coefficients obtained over a range of cutting speeds. The specific indentation force coefficient is used in an explicit formula of process damping which considers the radius and clearance angle of the cutting edge. It is experimentally shown that when the proposed process damping model is included, the accuracy of chatter stability predictions in turning and milling improves significantly at low cutting speeds.

Temperature Field Numerical Analysis of Machining Process Based on the Finite Element Analysis

2014 ◽  
Vol 621 ◽  
pp. 611-616 ◽  
Author(s):  
Yan Juan Hu ◽  
Yao Wang ◽  
Zhan Li Wang
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Cutting Parameters ◽  
Element Model ◽  
Machining Process ◽  
Element Analysis ◽  
Mechanical Coupling

In order to study the temperature field distribution in the process of machining, the finite element theory was used to establish the orthogonal cutting finite element model, and the key technologies were discussed simultaneously. By using ABAQUS software for cutting AISI1045 steel temperature field of numerical simulation, the conclusion about changing rule of cutting temperature field can be gotten. The results show that this method can efficiently simulate the distribution of temperature field of the workpiece, cutter and scraps, which is effected by thermo-mechanical coupling in metal work process. It provides the theory evidence for the intensive study of metal-cutting principle, optimizing cutting parameters and improving processing technic and so on.

scholarly journals Finite Element Analysis Of Influence Of Flank Wear Evolution On Forces In Orthogonal Cutting Of 42CrMo4 Steel

2017 ◽  
Vol 37 (1) ◽  
pp. 58-64
Author(s):  
Marek Madajewski ◽  
Zbigniew Nowakowski
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Cutting Force ◽  
Flank Wear ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Element Analysis ◽  
Force Magnitude ◽  
Feed Force ◽  
42Crmo4 Steel

Abstract This paper presents analysis of flank wear influence on forces in orthogonal turning of 42CrMo4 steel and evaluates capacity of finite element model to provide such force values. Data about magnitude of feed and cutting force were obtained from measurements with force tensiometer in experimental test as well as from finite element analysis of chip formation process in ABAQUS/Explicit software. For studies an insert with complex rake face was selected and flank wear was simulated by grinding operation on its flank face. The aim of grinding inset surface was to obtain even flat wear along cutting edge, which after the measurement could be modeled with CAD program and applied in FE analysis for selected range of wear width. By comparing both sets of force values as function of flank wear in given cutting conditions FEA model was validated and it was established that it can be applied to analyze other physical aspects of machining. Force analysis found that progression of wear causes increase in cutting force magnitude and steep boost to feed force magnitude. Analysis of Fc/Ff force ratio revealed that flank wear has significant impact on resultant force in orthogonal cutting and magnitude of this force components in cutting and feed direction. Surge in force values can result in transfer of substantial loads to machine-tool interface.

Study on the Orthogonal Cutting Process of Al7050T7451 with Uncoated and Coated Tools

2008 ◽  
Vol 392-394 ◽  
pp. 990-995 ◽  
Author(s):  
Hui Yue Dong ◽  
Pu Jin Huang ◽  
Y.B. Bi
Keyword(s):  
Finite Element ◽  
High Speed ◽  
High Strain ◽  
Bulk Material ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Machining Process ◽  
Workpiece Material ◽  
Coated Tool ◽  
The Impact

Tool wear during high speed machining process plays an important role in machining cost and efficiency. The purpose of this study is to examine the impact of tribological properties of coatings on cutting performance. Finite element methods (FEM) were used to model the effect of coated and uncoated cutting tools (K10) on the machinability of the aluminum alloy 7050T7451. Uncoated, Single coated, such as TiC, TiN and Al2O3 and multi-coated tool were studied. All finite element models were assumed to be plane strain. To achieve constitutive model of Al7050T7451 under conditions of machining that high strain rate, high strain and high temperature occur, high speed impact experiment and material drawing experiment were done. Comparison of FEM results shows that the highest temperatures in tools, the temperature change rates of different tools from surface to its bulk material, and the temperatures in chips are changed greatly. It also shows that the cutting temperature of coated tool is lower than uncoated tools, but cutting forces change very little. All these results show that coatings can be used to reduce adhesion between a tool and a workpiece material. The wear resistance of coated tool can be improved effectively and tool life is increased correspondingly.

Finite Element Simulation of Quick – Stop Experiments for Better Understanding of Chip Formation in Grinding

2011 ◽  
Vol 223 ◽  
pp. 764-773 ◽  
Author(s):  
Hans Werner Hoffmeister ◽  
Arne Gerdes
Keyword(s):  
Finite Element ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Element Model ◽  
Rake Angle ◽  
Grinding Process ◽  
Workpiece Material ◽  
Element Simulation ◽  
Single Grain

Several authors have previously simulated chip formation and their behaviour at the orthogonal cutting process. In contrast the chip formation for grinding was less investigated. This paper introduces a quick-stop device which allows easy investigation of the chip formation for the grinding process. For this process a workpiece forced by compressed air is shot against a single grain diamond with a large negative rake angle. Cutting forces were measured with a piezo electric sensor and discussed for a cutting speed range from 10m/s up to 30m/s. In Abaqus/Explicit a lagrangian formulation based finite element model was built to describe the chip formation for the grinding process. Chip formation, stress and heat distribution in the workpiece material can be calculated by this simulation model. The material behaviour was described with the Johnson Cook law. The simulation results show a good correlation compared to the quick stop experiments. All in all this simulation leads to a better understanding of the chip formation during grinding.

Analytical Modeling of Process Damping in Machining

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Oguzhan Tuysuz ◽  
Yusuf Altintas
Keyword(s):  
Contact Pressure ◽  
End Milling ◽  
Cutting Edge ◽  
Machining Process ◽  
Chatter Stability ◽  
Experimental Calibration ◽  
Process Damping ◽  
Low Speed ◽  
Edge Geometry ◽  
Five Axis

The machining process induced damping caused by the indentation of the cutting edge into the wavy cut surface greatly affects the process stability in low-speed machining of thermally resistant alloys and hardened steel, which have high-frequency vibration marks packed with short wavelengths. This paper presents an analytical model to predict the process damping forces and chatter stability in low-speed machining operations. The indentation boundaries are evaluated using the cutting edge geometry and the undulated surface waveform. Contact pressure due to the interference of the rounded and straight sections of the rigid cutting edge with the elastic-plastic work material is analytically estimated at discrete positions along the wavy surface. The overall contact pressure is obtained as a function of the cutting edge geometry, vibration frequency and amplitude, and the material properties of the workpiece. The resulting specific indentation force is evaluated by integrating the overall pressure along the contact length. Then, the process damping force is linearized by an equivalent specific viscous damping, which is used in the frequency domain chatter stability analysis. The newly proposed analytical process damping model is experimentally validated by predicting the chatter stability in orthogonal turning, end milling, and five-axis milling of flexible blades. It is shown that the proposed model can replace currently used empirical models, which require extensive experimental calibration approach or computationally prohibitive finite elements based numerical simulation methods.

Effect of Tool Flank Wear on the Orthogonal Cutting Process

2007 ◽  
Vol 329 ◽  
pp. 705-710 ◽  
Author(s):  
X.L. Zhao ◽  
Yong Tang ◽  
Wen Jun Deng ◽  
F.Y. Zhang
Keyword(s):  
Cutting Forces ◽  
Cutting Tool ◽  
Flank Wear ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Element Model ◽  
Cutting Process ◽  
Temperature Fields ◽  
Tool Flank Wear ◽  
Chip Separation

A coupled thermoelastic-plastic plane-strain finite element model is developed to study orthogonal cutting process with and without flank wear. The cutting process is simulated from the initial to the steady-state of cutting force and cutting temperature, by incrementally advancing the cutting tool forward. Automatic continuous remeshing is employed to achieve chip separation at the tool tip regime. The effect of the degree of the flank wear on the cutting forces and temperature fields is analyzed. With the flank wear increasing, the maximum cutting temperature values on the workpiece and cutting tool increase rapidly and the distribution of temperature changes greatly. The increase of tool flank wear produced slight increase in cutting forces but significant increase in thrust forces.

Implementation of Advanced Frictional Laws for Modelling of High Speed Machining

2013 ◽  
Vol 554-557 ◽  
pp. 2021-2028
Author(s):  
Yannick Senecaut ◽  
Michel Watremez ◽  
Damien Meresse ◽  
Laurent Dubar
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Element Model ◽  
Machining Process ◽  
Experimental Device ◽  
High Speed Machining ◽  
Input Parameters ◽  
Numerical Approaches

High-speed machining is submitted to economical and ecological constraints. Optimization of cutting processes must increase productivity, reduce tool wear and control residual stresses in the workpiece. Developments of numerical approaches to simulate accurately high-speed machining process are therefore necessary since in situ optimization is long and costly. To get this purpose, rheological behaviour of both antagonists and representative friction models at tool-chip interface has to be studied as encountered during high-speed machining process. The study is led with AISI 1045 steel and an uncoated carbide tool. An experimental device has been first designed to simulate the friction behaviour at the tool-chip interface only in the zone near the cutting edge. Several tests are then performed to provide experimental data and these data are used to define the friction coefficient versus to the contact pressure, the sliding velocity and the interfacial temperature by a new formulation frictional law given by Brocail et al (2010). A two-dimensional finite element model of orthogonal cutting is developed with Abaqus/explicit software. An Arbitrary Lagrangian-Eulerian (ALE) formulation is used to predict chip formation, temperature, chip-tool contact length, chip thickness, and cutting forces. This numerical model of orthogonal cutting is then validated by comparing these process variables to experimental and numerical results obtained by Filice et al. (2006). This model makes possible qualitative analysis of input parameters related to cutting process and frictional models. A sensitivity analysis has been performed on the main input parameters (coefficients of the Johnson-Cook law, contact and thermal parameters) with the finite element model. The interfacial law determined by Brocail et al (2010) is implemented on this finite element model of machining and leads to improve numerical approaches of machining. Nevertheless, even if this law enables to reduce results between experimental and numerical approaches, some differences are still substantial. The advanced friction law must be complemented for higher sliding velocities and this work using a new specific experimental device will be presented in the second part of this paper.

Numerical Simulation of Orthogonal Cutting Process of a Kind of Difficult-to-Cut Material

2006 ◽  
Vol 532-533 ◽  
pp. 925-928 ◽  
Author(s):  
Jing Sheng ◽  
Wei Zheng Yuan
Keyword(s):  
Orthogonal Cutting ◽  
Simulated Data ◽  
Element Model ◽  
Parametric Modeling ◽  
Constitutive Law ◽  
Cutting Process ◽  
Initial State ◽  
Workpiece Material ◽  
Mechanical Coupling ◽  
Chip Separation

A orthogonal cutting of a kind of difficult-to-cut material is simulated using a finite element model, which is considered dynamic effects, thermo-mechanical coupling, tool-chip friction, chip separation criteria. Marc program is the computational tool in the model. Johnson-Cook’s model is employed as the constitutive law for the workpiece material. The frictional behavior of the sticking and sliding tool-chip interface is described by Coulomb’s law. Remeshing technique and mesh adaptive technique are also used. The research mainly specializes plane strain and continuous flow chip. The emphasis is placed on the parametric modeling of tool and workpiece. Then the cutting force and temperature in cutting process from initial state to steady state is conducted by simulation. Finally the Experimental value is compared with the simulated data.

scholarly journals An Evaluation of Ploughing Models for Orthogonal Machining

1999 ◽  
Vol 121 (4) ◽  
pp. 550-558 ◽  
Author(s):  
D. J. Waldorf ◽  
R. E. DeVor ◽  
S. G. Kapoor
Keyword(s):  
Cutting Tool ◽  
Metal Removal ◽  
Orthogonal Cutting ◽  
Cutting Edge ◽  
Machining Process ◽  
Separation Point ◽  
Workpiece Material ◽  
Orthogonal Machining ◽  
Edge Component ◽  
Material Separation

An analytical comparison is made between two basic models of the flow of workpiece material around the edge of an orthogonal cutting tool during steady-state metal removal. Each has been the basis for assumptions in previous studies which attempt to model the machining process, but no direct comparison had been made to determine which, if either, is an appropriate model. One model assumes that a separation point exists on the rounded cutting edge while the other includes a stable build-up adhered to the edge and assumes a separation point at the outer extreme of the build-up. Theories of elastic-plastic deformation are employed to develop force predictions based on each model, and experiments are performed on 6061-T6 aluminum alloy to evaluate modeling success. The experiments utilize unusually large cutting edge radii to isolate the edge component of the total cutting forces. Results suggest that a material separation point on the tool itself does not exist and that the model that includes a stable build-up works better to describe the experimental observations.

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