Role of Tool Flank Wear and Machining Speed in Developing of Residual Stress in Machined Surface During High Speed Machining of Titanium Alloys

2015 ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
High Speed ◽  
Flank Wear ◽  
Tool Geometry ◽  
High Speed Machining ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
Machining Speed

Residual stresses generated from finish machining have a significant impact on the fatigue life of mechanical components by controlling crack initiation and propagation processes in their near subsurface. As governing variables, tool geometry, tool wear, machining parameter, work material property, and lubrication conditions have been widely studied to determine their effects on residual stress pattern in machined surface and subsurface. Among those parameters, tool flank wear was seldom fully investigated although tool flank wear, as well as machining speed, has been identified as the most important contributor to residual stress. Especially, tool flank wear becomes more significant due to the poor work thermal property during the high speed machining of titanium Ti-6Al-4V alloy. This study aims to investigate the combined role of tool flank wear and machining speed in developing residual stress in the machining of titanium alloy using finite element method. A microstructure sensitive material model based on Self Consistent Method (SCM) is adopted to incorporate the phase state and its transformations during machining cycle. Critical flank wear land and corresponding machining speeds are identified, beyond which compressive residual stresses are transferred into tensile residual stresses. High machining speeds demonstrate a distinct influence on residual stresses by means of promoting tool flank wear rate. The numerical simulation results are validated by empirical data provided in previous research.

FEM Simulation of the Residual Stress in the Machined Surface Layer for High-Speed Machining

2006 ◽  
Vol 315-316 ◽  
pp. 140-144 ◽  
Author(s):  
Su Yu Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Z.J. Lv
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Surface Layer ◽  
Residual Stresses ◽  
High Speed ◽  
Metal Cutting ◽  
Orthogonal Cutting ◽  
High Speed Machining ◽  
Machined Surface ◽  
Cutting Model

An orthogonal cutting model was presented to simulate high-speed machining (HSM) process based on metal cutting theory and finite element method (FEM). The residual stresses in the machined surface layer were obtained with various cutting speeds using finite element simulation. The variations of residual stresses in the cutting direction and beneath the workpiece surface were studied. It is shown that the thermal load produced at higher cutting speed is the primary factor affecting the residual stress in the machined surface layer.

scholarly journals 3D Hybrid Numerical Model of Residual Stresses: Numerical—Sensitivity to Cutting Parameters When Turning 15-5PH Stainless Steel

2021 ◽  
Vol 5 (3) ◽  
pp. 70
Author(s):  
Alexandre Mondelin ◽  
Frédéric Valiorgue ◽  
Joël Rech ◽  
Michel Coret
Keyword(s):  
Stainless Steel ◽  
Residual Stresses ◽  
Hybrid Model ◽  
Flank Wear ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Tool Geometry ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
Residual Stress State

This paper investigates the residual stresses induced by a longitudinal turning operation in 15-5PH martensitic stainless steel. An experimental investigation has quantified the sensitivity of residual stresses to cutting speed, feed, tool geometry and tool flank wear. In parallel, a 3D hybrid model, previously developed, has been applied to each case study. This modelling approach consists of replacing tooling and chipping by equivalent thermal and mechanical loadings. These equivalent loadings are moved onto the machined surface to compute the final residual stress state. It has shown that tool geometry and tool flank wear have a dominant effect on residual stresses compared to cutting speed and feed rate. However, cutting speed influences the intensity of the compressive peak, to some extent, whereas feed influences the affected depth. This work has also shown that the 3D hybrid model is able to predict residual stresses, as well as the sensitivity to cutting parameters, with reasonable agreement.

FEA-Based Comparative Investigation on High Speed Machining of Aluminum Alloys AA6061-T6 and AA7075-T651

2017 ◽  
Vol 261 ◽  
pp. 347-353 ◽  
Author(s):  
Walid Jomaa ◽  
Victor Songmene ◽  
Philippe Bocher ◽  
Augustin Gakwaya
Keyword(s):  
Aluminum Alloys ◽  
Residual Stresses ◽  
Chip Formation ◽  
High Speed ◽  
Cutting Temperature ◽  
Numerical Data ◽  
Formation Mechanisms ◽  
High Speed Machining ◽  
Machined Surface ◽  
Initial Yield Stress

Independent research studies have shown notable dissimilarity in the machining behaviour of aluminum alloys AA6061−T6 and AA7075−T651 commonly used in automotive and aeronautical applications. The present work attempts to investigate this dissimilarity based on experimental and numerical data with a focus on chip formation and generated residual stresses under similar high−speed machining (HSM) conditions. The numerical data were calculated by a finite element modeling (FEM) developed using DeformTM 2D software. The results showed that both studied alloys exhibit different chip formation mechanisms and residual stress states at the machined surfaces. On one hand, the AA6061−T6 alloy generates continuous chips and tensile residual stresses whereas the AA7075−T651 alloy produces segmented chips and compressive residual stresses. FEM results showed that the AA6061−T6 alloy generates lower cutting temperature at the tool−chip interface along with higher equivalent total strains at the machined surface as compared to the AA7075−T651 alloy. Based on the experimental and numerical results, it was pointed out that the differences in terms of thermal conductivity and initial yield stress are the main reasons explaining the dissimilarity observed.

Surface Integrity of Die Material in High Speed Hard Machining, Part 1: Micrographical Analysis

1999 ◽  
Vol 122 (4) ◽  
pp. 620-631 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi
Keyword(s):  
Tool Wear ◽  
Residual Stresses ◽  
Tool Steel ◽  
Surface Integrity ◽  
High Speed ◽  
Cutting Conditions ◽  
Metallographic Analysis ◽  
Tool Geometry ◽  
Machined Surface ◽  
Geometrical Defects

The effects of cutting conditions and tool wear on chip morphology and surface integrity during high speed machining of D2 tool steel (60–62 Hrc) are investigated experimentally and analytically in this paper. Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this investigation. The chips and the subsurface of the workpiece are examined using optical and scanning electron microscopy. Microhardness measurements are performed on the surface and subsurface of the workpiece. The X-ray diffraction technique is used to measure the residual stresses induced in the machined surface. The paper is divided into two parts. Part 1 presents the results obtained from the micrographical analysis of the chips and the surfaces produced. Part 2 deals with microhardness and residual stresses of the machined surface. The micrographical analysis of the chips produced shows that different mechanisms of chip formation exist depending on the magnitude of the cutting pressure and tool wear. Saw toothed chips are produced during the machining of D2 tool steel if the cutting pressure exceeds approximately 4000 MPa. The metallographic analysis of the surface produced illustrates the damaged surface region that contains geometrical defects and changes in the subsurface metallurgical structure. The types of surface damage are dependent on the cutting conditions, tool geometry and the magnitude of the wear lands. [S1087-1357(00)00104-0]

Optimization of Tensile Residual Stress on Machined Surface in MQL Turning

2015 ◽  
Vol 713-715 ◽  
pp. 209-212 ◽  
Author(s):  
Xia Ji ◽  
Alexander H. Shih ◽  
Manik Rajora ◽  
Ya Min Shao ◽  
Steven Y. Liang
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Minimum Quantity Lubrication ◽  
Optimization Procedure ◽  
Stress Generation ◽  
Tool Geometry ◽  
Machined Surface ◽  
Good Surface ◽  
Optimal Inputs ◽  
Marquardt Algorithm

Producing good surface integrity is one of the main challenges of the machining industry. The increase of the utilization of minimum quantity lubrication (MQL) in order to reduce the amount of lubrication induced a lack of understanding of the physics behind the residual stress generation. Residual stress in the machined surface and subsurface is affected by materials, machining conditions, and tool geometry. These residual stresses could affect the service qualify and component life significantly. Residual stress can be determined by empirical or numerical experiments for selected configurations, even if both are expensive procedures. This paper presents a hybrid neural network that is trained using Simulated Annealing (SA) and Levenberg-Marquardt Algorithm (LM) in order to predict the values of residual stresses in cutting and radial direction after the MQL face turning process accurately. First, SA is used to train the weight and bias values of the ANN after which LM is used to fine tune the values trained by SA. Then, based on the predictions, an optimization procedure, using Genetic Algorithm (GA), is applied in order to find the best cutting conditions. At each generation, GA suggests a population of inputs that are then sent to the trained ANN in order to predict the residual stresses. The objective is to find the optimal inputs that minimize the tensile stress on the machined surface.

Effect Residual Stress on Material Hardness by Finite Element Simulation during the Process of High Speed Cutting

2016 ◽  
Vol 719 ◽  
pp. 23-27
Author(s):  
De Weng Tang ◽  
Zhi Feng He ◽  
Xi Jian Lv ◽  
Cong Peng
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
High Speed ◽  
Cutting Temperature ◽  
Element Model ◽  
Residual Tensile Stress ◽  
Machined Surface ◽  
High Speed Cutting ◽  
Material Hardness

Residual stresses induced during the process of high speed cutting are very critical due to safety and corrosion resistance. Based on the nonlinear finite element code DEFORM, thermodynamic couple model of residual stress was built. Effect distribution of residual stresses on three different materials physical properties of hardness are analyzed by using the finite element model during the process of high speed cutting. The results show that metal material hardness is the key factors to residual stress. When materials’ hardness is higher, residual tensile stress is easy to form on the machined surface due to high cutting temperature, such as hardened steel SKD11(HRC=62). To lower hardness material, residual compressive stress is generated on the machined surface for plastic deformation, such as softer materials 7075Al (HRC=23).

scholarly journals Effects of Tool Wear on Machined Surface Integrity During Milling of Inconel 718

2021 ◽  
Author(s):  
Liang Tan ◽  
Changfeng Yao ◽  
Dinghua Zhang ◽  
Minchao Cui ◽  
Xuehong Shen
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Tool Wear ◽  
Surface Integrity ◽  
Inconel 718 ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
Machined Surface Integrity

Abstract This paper investigates the effects of tool wear on the machined surface integrity characteristics, including the surface roughness, surface topography, residual stress, microhardness and microstructure, during ball-end milling of Inconel 718. Tool wear, tool lifetime, and cutting force are measured. In addition, a two-dimensional finite element-based model is developed to investigate the cutting temperature distribution in the chip–tool–workpiece contact area. Results show that the ball nose end mill achieves tool lifetime of approximately 350 min. The cutting forces increase sharply with a greater tool flank wear width, while the highest cutting temperature has a decreasing tend at a flank wear width of 0.3 mm. Higher tool flank wear width produces larger surface roughness and deteriorative surface topography. A high-amplitude (approximately −700 MPa) and deep layer (approximately 120 mm) of compressive residual stress are induced by a worn tool with 0.3 mm flank wear width. The surface microhardness induced by new tool is larger than that induced by worn tool. Plastic deformation and strain streamlines are observed within 10 mm depth beneath the surface. The results in this paper provide an optimal tool wear criterion which integrates the surface integrity requirements and the tool lifetime for ball-end finish milling of Inconel 718.

Surface Integrity of Die Material in High Speed Hard Machining, Part 2: Microhardness Variations and Residual Stresses

1999 ◽  
Vol 122 (4) ◽  
pp. 632-641 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Stress Distribution ◽  
Residual Stresses ◽  
High Speed ◽  
Residual Stress Distribution ◽  
Depth Of Cut ◽  
Hard Machining ◽  
Machined Surface ◽  
Workpiece Surface

The main objective of this paper is to investigate the quality and integrity of the surface produced during high speed hard machining (HSHM) of D2 tool steel in its hardened state (60–62 HRc). Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this study. The results obtained from the micro-graphical analysis of the surface produced are presented in Part 1 of this paper. In Part 2 micro-hardness and residual stress analyses are presented. Microhardness measurements are conducted beneath the machined surface. X-ray diffraction analysis is performed to obtain the residual stress distribution beneath the surface. Analytically, a 3-D thermo-elasto-plastic finite element model is developed to predict the residual stresses induced in the workpiece surface. In the model the cutting zone is specified based on the tool condition (i.e., sharp or worn). The finite element analysis demonstrates the significant effect of the heat generated during cutting on the residual stress distribution. The results illustrate the possibility of minimizing the high tensile residual stresses produced in the workpiece surface, by selecting the appropriate depth of cut. A good correlation between the analytical and predicted residual stress is obtained. [S1087-1357(00)00804-2]

Finite Element Simulation of Residual Stress on the Surface in the Cutting Considering Tool Flank Wear

2010 ◽  
Vol 431-432 ◽  
pp. 338-341
Author(s):  
Hai Tao Liu ◽  
Ya Zhou Sun ◽  
Ze Sheng Lu
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Finite Element Simulation ◽  
Flank Wear ◽  
Great Influence ◽  
Machining Accuracy ◽  
Surface Residual Stress ◽  
Machined Surface ◽  
Tool Flank Wear ◽  
Element Simulation

Deformation caused by residual stress has been one of the main reasons influencing the machining accuracy, studies on machining residual stress should be performed. The tool flank wear on the cutting process has great influence on cutting heat which will infulence the distribution of residual stress, therefore,we should do the finite element simulation of cutting tool flank wear on the heat-affected firstly,then simulate and forecast the surface residual stress, studies on the effect of tool flank wear on the distribution of machined surface residual stress Johnson-Cook’s coupled thermal-mechanical model is used as workpiece material model, thermal-displacement coupled brick are used to mesh, while friction between tool and work piece uses modified Coulomb's law whose slide friction area is combined with sticking friction. By means of FEA, residual stress on the machined surface and cutting temperature under different tool flank wear conditions are obtained. The results are compared and analyzed, and then we can get the fundamental influencing law on machined surface residual stress of tool flank wear.

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