Finite Element Modeling of Orthogonal Metal Cutting

1991 ◽  
Vol 113 (3) ◽  
pp. 253-267 ◽  
Author(s):  
K. Komvopoulos ◽  
S. A. Erpenbeck

The finite element method was used to model chip formation in orthogonal metal cutting. Emphasis was given on analyzing the effect of important factors, such as plastic flow of the workpiece material, friction at the tool-workpiece interface, and wear of the tool, on the cutting process. To simulate separation of the chip from the workpiece, superposition of two nodes at each nodal location of a parting line of the initial mesh was imposed. According to the developed algorithm, the superimposed nodes were constrained to assume identical displacements, until approaching to a specified small distance from the tool tip. At that juncture, the displacement constraint was removed and separation of the nodes was allowed. Under the usual plane strain assumption, quasi-static finite element simulations of orthogonal metal cutting were performed for interfacial friction coefficients equal to zero, 0.15, and 0.5 and unworn or worn (cratered) tools having a strongly adherent built-up edge. To investigate the significance of the deformation of the workpiece material on the cutting process, elastic-perfectly plastic and elastic-plastic with isotropic strain hardening and strain rate sensitivity constitutive laws were used in the analysis. For simplicity, the tool material and the built-up edge were modeled as perfectly rigid. In all cases analyzed, the cutting speed and depth of cut were set equal to 183 m/min and 1.27 mm, respectively. Experiments confirmed that cutting of AISI 4340 steel with ceramic-coated tools under similar conditions led to the development of a built-up edge and the formation of continuous chips. The dimensions of the crater, assumed in the finite element simulations involving a cratered tool, were also determined from the same cutting experiments. Spatial distributions of the equivalent total plastic strain and the von Mises equivalent stress corresponding to steady-state cutting conditions and the normal and shear stresses at the rake face are contrasted and interpreted qualitatively in terms of critical parameters. The influence of interfacial friction, metal flow characteristics, and wear at the rake face of the tool on the steady-state magnitudes of the cutting forces, shear plane angle, chip thickness, and chip-tool contact length are also elucidated. Several aspects of the metal cutting process predicted by the finite element model agreed well with experimental results and phenomenological observations.

2008 ◽  
Vol 53-54 ◽  
pp. 71-76 ◽  
Author(s):  
Wen Jun Deng ◽  
C. Li ◽  
Wei Xia ◽  
X.Z. Wei

A coupled thermo-mechanical model of plane-strain orthogonal metal cutting including burr formation is presented using the commercial finite element code. A simulation procedure based on Normalized Cockroft-Latham damage criterion is proposed for the purpose of better understanding the burr formation mechanism and obtaining a quantitative analysis of burrs at exit. The cutting process is simulated from the transient initial chip formation state to the steady-state of cutting, and then to tool exit transient chip flow, by incrementally advancing the cutting tool. The effects of cutting condition on the non-steady-state chip flow while tool exit can be investigated using the developed finite element model.


1995 ◽  
Vol 117 (1) ◽  
pp. 84-93 ◽  
Author(s):  
A. J. Shih

The development and implementation of a plane-strain finite element method for the simulation of orthogonal metal cutting with continuous chip formation are presented. Detailed work-material modeling, including the effects of elasticity, viscoplasticity, temperature, large strain, and high strain-rate, is used to simulate the material deformation during the cutting process. The unbalanced force reduction method and sticking-sliding friction behavior are implemented to analyze the cutting process. The deformation of the finite element mesh and comparisons of residual stress distributions with X-ray diffraction measurements are presented. Simulation results along the primary and secondary deformation zones and under the cut surface, e.g., the normal and shear stresses, temperature, strain-rate, etc., are presented revealing insight into the metal cutting process.


Author(s):  
Bin Shi ◽  
Helmi Attia ◽  
Nejah Tounsi

To achieve high performance machining, modeling of the cutting process is necessary to predict cutting forces, residual stresses, tool wear, and burr formation. A major difficulty in the modeling of the cutting process is the description of the material constitutive law to reflect the severe plastic deformation encountered in the primary and the secondary deformation zones under high strains, strain rates, and temperatures. A critical literature review shows that the available methods to identify the material constitutive equation for the cutting process may lead to significant errors due to their limitations. To overcome these limitations, a novel methodology is developed in this study. Through conceptual considerations and finite element simulations, the characteristics of the stress, strain, strain rate, and temperature fields in the primary shear zone were established. Using this information and applying the principles of the theory of plasticity, heat transfer, and mechanics of the orthogonal metal cutting, a new distributed primary zone deformation model is developed to describe the distributions of the effective stress, effective strain, effective strain rate, and temperature in the primary shear zone. This analytical model is assessed by comparing its predictions with finite element simulation results under a wide range of cutting conditions using different materials. Experimental validation of this model will be presented in Part II of this study.


2017 ◽  
Vol 261 ◽  
pp. 339-346 ◽  
Author(s):  
Evaggelos Kaselouris ◽  
Theodoros Papadoulis ◽  
Elenh Variantza ◽  
Andreas Baroutsos ◽  
Vasilios Dimitriou

The capability of the explicit numerical methods to simulate accurately the real cutting process is investigated in this research work. Smoothed particle hydrodynamics - SPH, classical Lagrangian finite element method - FEM and Multi-Material Arbitrary Lagrangian Eulerian - ALE methods are chosen for the modeling and simulation of the orthogonal metal cutting process of AISI H13 in LS-DYNA. The cutting tool is modeled as a rigid FEM body that incrementally penetrates into the flexible deformable workpiece. At each numerical model, the dynamic elastoplastic behavior of the workpiece material is investigated by taking into account the Johnson-Cook (J-C) constitutive strength material model. The influence of the J-C parameter values found in literature to the models is explored. The obtained numerical SPH, FEM and ALE results of the estimated cutting and thrust forces, stress, plastic strain and thermal distributions are compared with results found in the literature. This comparison, leads to valuable conclusions for the performance of the three methods, concerning the approximation accuracy, model development complexity and computational time demands. Based on these conclusions the SPH method is chosen to simulate the experimentally performed orthogonal cut of AISI 1045. The obtained SPH numerical results outline its advantages among the other explicit simulation methods.


2004 ◽  
Vol 471-472 ◽  
pp. 582-586 ◽  
Author(s):  
Shi Jin Chen ◽  
Q.L. Pang ◽  
K. Cheng

In this paper, a finite element model of a two-dimensional orthogonal metal cutting process is used to simulate the chip formation, cutting forces, stress, strain and temperature distributions. Two deformable parts are involved in this model: the workpiece and the cutting tool. To make the results of the simulation agree the orthogonal cutting test better, the separation surface between the chip and the machined surface is not predefined in this simulation. The chip-separation criterion is based on the Johnson and Cook law. This work will help as a reference to tackle more complex cutting processes such as oblique and discontinuous cutting.


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