scholarly journals Predictive modelling of cutting forces in end milling of titanium alloy Ti6Al4V

2016 ◽  
Vol 232 (9) ◽  
pp. 1523-1534 ◽  
Author(s):  
Yun Chen ◽  
Huaizhong Li ◽  
Jun Wang
Keyword(s):  
Titanium Alloy ◽  
Predictive Model ◽  
End Milling ◽  
Mechanistic Model ◽  
Orthogonal Cutting ◽  
Cutting Edge ◽  
Material Strength ◽  
Force Model ◽  
Serrated Chip ◽  
Titanium Alloy Ti6al4v

A cutting force model, based on a predictive model for orthogonal cutting, is developed for force predictions in end milling of titanium alloy Ti6Al4V. The model assumes a semi-stationary process for the serrated chip formation. The Johnson–Cook material model that couples strain hardening, strain rate sensitivity and thermal softening effects is applied to represent the material strength. A thermal model considering the tool thermal properties is integrated to account for the high temperature rise due to the low thermal conductivity of Ti6Al4V. To extend the predictive model to milling, the end mill is discretised into several axial slices, and an equivalent cutting edge is used to include the end cutting edge effect caused by the first axial slice. The model is assessed by comparing its prediction with the experimental results and a mechanistic model for verification. The results show that the proposed model outperforms the mechanistic model with higher accuracy in force prediction.

The prediction of cutting force in end milling titanium alloy (Ti6Al4V) with polycrystalline diamond tools

2016 ◽  
Vol 231 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Wencheng Pan ◽  
Songlin Ding ◽  
John Mo
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Cutting Forces ◽  
End Milling ◽  
Polycrystalline Diamond ◽  
Force Model ◽  
Machining Parameters ◽  
Diamond Tools ◽  
Cutting Coefficients ◽  
Titanium Alloy Ti6al4v

Cutting force coefficients were conventionally described as the power function of instantaneous uncut chip thickness. However, it was found that the changes in the three controllable machining parameters (cutting speed, feed and axial cutting depth) could significantly affect the values of cutting coefficients. An improved cutting force model was developed in this article based on the experimental investigation of end milling titanium alloy (Ti6Al4V) with polycrystalline diamond tools. The relationships between machining parameters and cutting force are established based on the introduction of the new cutting coefficients. By integrating the effects of varying cutting parameters in the prediction model, cutting forces and the fluctuation of cutting force in each milling cycle were calculated. Validation experiments show that the predicted peak values of cutting forces highly match the experimental results; the accuracy of the model is up to 90% in predicting instantaneous cutting forces.

Inverse identification of modified Johnson–Cook model for cutting titanium alloy Ti6Al4V using firefly algorithm

2019 ◽  
Vol 234 (3) ◽  
pp. 584-599 ◽  
Author(s):  
Jinhua Zhou ◽  
Junxue Ren ◽  
Yong Jiang
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Firefly Algorithm ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Process ◽  
Zone Model ◽  
Serrated Chip ◽  
Titanium Alloy Ti6al4v ◽  
Cook Model

The original Johnson–Cook equation fails to describe the significant thermal softening phenomenon of flow stress in cutting process of titanium alloy Ti6Al4V. Recently, some researchers developed some modified Johnson–Cook models of Ti6Al4V by introducing some additional parameters. But effective parameter identification method is unavailable in those research works. In this work, an inverse approach is developed to determine the additional parameters. A modified Johnson–Cook model with the hyperbolic tangent function is adopted, in which four unknown parameters need to be determined. The parameter assessment is taken as an optimization process based on the unequal division parallel-sided shear zone model. Along with the measured cutting force and chip thickness, the firefly algorithm is introduced to search for the parametric optimal solution. Those four parameters are determined when the difference between the predicted and experimental effective stress at shear plane reaches its minimum. The identified constitutive model is subsequently verified by finite element simulation of orthogonal cutting process, and compared with previous different material models. With the identified modified Johnson–Cook model, the serrated chip is observed in all the simulations. A good agreement between verification experiments and simulations is achieved. An acceptable prediction accuracy with an error of 10.28% on cutting force and an error of 18.12% on chip size is achieved.

scholarly journals Analytical modelling of cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V

2014 ◽  
Vol 229 (6) ◽  
pp. 1122-1133 ◽  
Author(s):  
Yun Chen ◽  
Huaizhong Li ◽  
Jun Wang
Keyword(s):  
Titanium Alloy ◽  
Cutting Forces ◽  
Chemical Reactivity ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Analytical Modelling ◽  
Shear Instability ◽  
Published Data ◽  
Machining Processes ◽  
Titanium Alloy Ti6al4v

Titanium and its alloys are difficult to machine due to their high chemical reactivity with tool materials and low thermal conductivity. Chip segmentation caused by the thermoplastic instability is always observed in titanium machining processes, which leads to varied cutting forces and chip thickness, etc. This paper presents an analytical modelling approach for cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V. The catastrophic shear instability in the primary shear plane is assumed as a semi-static process. An analytical approach is used to evaluate chip thicknesses and forces in the near-orthogonal cutting process. The shear flow stress of the material is modelled by using the Johnson–Cook constitutive material law where the strain hardening, strain rate sensitivity and thermal softening behaviours are coupled. The thermal equations with non-uniform heat partitions along the tool–chip interface are solved by a finite difference method. The model prediction is verified with experimental data, where a good agreement in terms of the average cutting forces and chip thickness is shown. A comparison of the predicted temperatures with published data obtained by using the finite element method is also presented.

Development of Analytical Force Model for End Milling of Magnesium Matrix Composites

2020 ◽  
Author(s):  
Nishita Anandan ◽  
M. Ramulu
Keyword(s):  
End Milling ◽  
Coefficient Of Thermal Expansion ◽  
Cutting Edge ◽  
Force Model ◽  
Matrix Composites ◽  
Magnesium Metal ◽  
Magnesium Matrix Composites ◽  
The Matrix ◽  
Thrust Forces ◽  
Good Agreement

Abstract An analytical approach to predict the cutting forces in end milling of magnesium metal matrix composite is presented in this study. The model was developed by identifying three events that occur when the cutting edge encounters the composite, when an element of the cutting edge encounters just the particles, it may fracture the particle, when the element encounters pure ductile matrix, plastic deformation occurs and when the element is in contact with both the particle and matrix, particle debonding occurs due to mismatch in coefficient of thermal expansion. The probability of these events was estimated using the particle concentration and the distribution in the matrix. A cutting force model is developed by considering the stresses and forces experienced by the cutting edge contributed by these events. The predicted feed forces and the measured forces are in good agreement for most of the cutting conditions. While, the predictive thrust forces were found to diverge at higher feed of 1 mm/rev.

A Mechanistic Force Model of the 5-Axis Milling Process

2000 ◽  
Author(s):  
Paul A. Clayton ◽  
Mohamed A. Elbestawi ◽  
Tahany El-Wardany ◽  
Dan Viens
Keyword(s):  
High Speed ◽  
Mechanistic Model ◽  
Back Propagation ◽  
High Speed Steel ◽  
Cutting Edge ◽  
Analytic Description ◽  
Force Model ◽  
Force Output ◽  
Five Axis ◽  
Milling Force Model

Abstract This paper presents a five-axis milling force model that can incorporate a variety of cutters and workpiece materials. The mechanistic model uses a discretized cutting edge to calculate an area of intersection which is multiplied by the specific cutting pressure to produce a force output along the primary cartesian coordinate system. By using an analytic description of the cutting edge with a non-specific cutter and workpiece intersection routine, a model was created that can describe a variety of cutting situations. Furthermore, a back propagation neural network is used to calibrate the model, providing robustness and scalability to the calibration process. Testing was performed on 1020 steel using various cutting parameters with a high speed steel two flute cutter and a tungsten carbide insert cutter. Furthermore, both linear cuts and a test die surface yielded good agreement between predicted and measured results.

scholarly journals Constitutive Model and Cutting Simulation of Titanium Alloy Ti6Al4V after Heat Treatment

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4145
Author(s):  
Xiaohua Qian ◽  
Xiongying Duan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Titanium Alloy ◽  
Orthogonal Cutting ◽  
Treatment Method ◽  
Dynamic Mechanical Properties ◽  
Ti6al4v Alloy ◽  
Stress Strain ◽  
Cutting Simulation ◽  
Titanium Alloy Ti6al4v

As a typical high specific strength and corrosion-resistant alloy, titanium alloy Ti6Al4V is widely used in the aviation, ocean, biomedical, sport, and other fields. The heat treatment method is often used to improve the material mechanical properties. To investigate the dynamic mechanical properties of titanium alloy Ti6Al4V after heat treatment, dynamic compressive experiments under high temperature and high strain rate were carried out using split Hopkinson press bar (SHPB) equipment. The stress–strain curves of Ti6Al4V alloy under different temperatures and strain rates were obtained through SHPB compressive tests. The Johnson–Cook (J–C) constitutive equation was used for expressing the stress–strain relationship of titanium alloy under large deformation. In addition, the material constants of the J–C model were fitted based on the experimental data. An orthogonal cutting simulation was performed to investigate the cutting of Ti6Al4V alloy under two different numerical calculation methods based on the established J–C model using the finite element method (FEM). The simulation results confirm that the adiabatic mode is more suitable to analyze the cutting of Ti6Al4V alloy.

Voxel Based Cutting Force Simulation of Ball End Milling Considering Cutting Edge Around Center Web

2018 ◽  
Author(s):  
Isamu Nishida ◽  
Takaya Nakamura ◽  
Ryuta Sato ◽  
Keiichi Shirase
Keyword(s):  
Cutting Force ◽  
End Milling ◽  
Chip Thickness ◽  
Previous Method ◽  
Cutting Edge ◽  
Force Model ◽  
End Mill ◽  
Uncut Chip Thickness ◽  
Ball End Mill ◽  
Tool Rotation

A new method, which accurately predicts cutting force in ball end milling considering cutting edge around center web, has been proposed. The new method accurately calculates the uncut chip thickness, which is required to estimate the cutting force by the instantaneous rigid force model. In the instantaneous rigid force model, the uncut chip thickness is generally calculated on the cutting edge in each minute disk element piled up along the tool axis. However, the orientation of tool cutting edge of ball end mill is different from that of square end mill. Therefore, for the ball end mill, the uncut chip thickness cannot be calculated accurately in the minute disk element, especially around the center web. Then, this study proposes a method to calculate the uncut chip thickness along the vector connecting the center of the ball and the cutting edge. The proposed method can reduce the estimation error of the uncut chip thickness especially around the center web compared with the previous method. Our study also realizes to calculate the uncut chip thickness discretely by using voxel model and detecting the removal voxels in each minute tool rotation angle, in which the relative relationship between a cutting edge and a workpiece, which changes dynamically during tool rotation. A cutting experiment with the ball end mill was conducted in order to validate the proposed method. The results showed that the error between the measured and predicted cutting forces can be reduced by the proposed method compared with the previous method.

Study on Determination of Friction Model at the Tool-Chip Interface of Titanium Alloy Ti6Al4V Based on Orthogonal Cutting

2011 ◽  
Vol 117-119 ◽  
pp. 1788-1791
Author(s):  
Yue Feng Yuan ◽  
Wu Yi Chen
Keyword(s):  
Titanium Alloy ◽  
Cutting Force ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Friction Model ◽  
Carbide Tool ◽  
Orthogonal Turning ◽  
Titanium Alloy Ti6al4v

It is necessary for cutting simulation to determine the friction model at the tool-chip interface suitable for metal cutting process. Cutting force experiments in orthogonal turning titanium alloy TI6AL4V are carried out with cement carbide tool KW10. The Coulomb frictions at the tool-chip interface are calculated based on measured cutting force, and the friction model is regressed, where cutting speed and feed rate are presented.

FEA Simulation of the Influence of Cutting Parameters on Serrated Chip Formation in Machining Titanium Alloy Ti-6Al-4V

2012 ◽  
Vol 500 ◽  
pp. 152-156
Author(s):  
Zeng Hui Jiang ◽  
Ji Lu Feng ◽  
Xiao Ye Deng
Keyword(s):  
Titanium Alloy ◽  
Chip Formation ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Element Model ◽  
Serrated Chip ◽  
Wide Range ◽  
Serrated Chip Formation ◽  
Fea Simulation

A finite element model of a two dimensional orthogonal cutting process is developed. The simulation uses standard finite software is able to solve complex thermo-mechanical problems. A thermo-visco-plastic model for the machined material and a rigid cutting tool were assumed. One of the main characteristic of titanium alloy is serrated shape for a wide range of cutting conditions. In order to understand the influence of cutting parameters on the chip formation when machining titanium alloy Ti-6Al-4V. The influence of the cutting speed,the cutting depth and the feed on the chip shape giving rise to segmented chips by strain localisation is respectively discussed.

Effect of Tool Wear on Surface Qualities in Milling of TC4

2016 ◽  
Vol 836-837 ◽  
pp. 132-138 ◽  
Author(s):  
Shu Cai Yang ◽  
Xiao Yang Cui ◽  
Yu Hua Zhang ◽  
Zhi Wei Wang
Keyword(s):  
Surface Roughness ◽  
Titanium Alloy ◽  
Tool Wear ◽  
Surface Quality ◽  
End Milling ◽  
Great Influence ◽  
Chip Morphology ◽  
Milling Process ◽  
Serrated Chip ◽  
Quality Surface

Tool wear is easy occurred in titanium alloy milling process which will affect the surface quality. Surface roughness and surface morphology as an important index to describe and evaluate the surface quality has a great influence on service performance. Therefore, the study on the effect of tool wear on surface qualities is important to improve the surface integrity of titanium alloy parts. Cutting radius of ball-end milling cutter is solved to analyze the effect of tool wear on the cutting radius. The tool wear and the surface qualities of TC4 are achieved through wear experiment. And then the influence law of tool wear on surface qualities and chip morphology are analyzed. The results show that surface roughness value decrease firstly and then increases and that chip morphology with flank wear increase from the unit chip to the serrated chip.

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