Effect Of Edge Radius Research Articles

Effects of Edge Radius and Coating Thickness on the Cutting Performance of AlCrN-Coated Tool

High-speed machining is a practical way to attain high productivity with lower costs. Under this condition, the tool geometry needs to be optimized to sustain high cutting forces and temperatures. The sharpness of the cutting edge and the coating thickness (CT) are two key parameters that affect the tool’s performance. While a sharp edge eases the cutting process, it causes a high stress concentration, which increases the wear rate and eventual edge fracture. In this study, we use a combination of finite element simulations and experimental testing to evaluate the effects of CT ( 1–3 μm), edge radius (rβ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$r_{\\beta }$$\\end{document} , 6–15 μm), and coefficient of friction (μ=0-0.2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu = 0 - 0.2$$\\end{document}) on the stress distribution at the cutting edge. Our simulations showed that the larger the CT, the higher the stress magnitude inside the coating, but the lower the maximum stress depth percentile. Considering an industrial case of cutting steel workpieces using AlCrN-coated tungsten carbide tools under given cutting parameters, our simulations suggested an optimum CT of 3 μm. By manufacturing a series of milling tools with different CTs and edge radii, we validated the simulation results using a set of well-controlled milling experiments. Finally, the edge radius should be selected considering the size of rake/flank angle mainly to control stress distribution over the cutting edge.

Effects of Leading Edge Radius on Stall Characteristics of Rotor Airfoil

The effects of leading edge radius on the static and dynamic stall characteristics of rotor airfoils are investigated. Initially, a parametric airfoil (PARFOIL) method is employed to generate four morphed airfoils with different leading edge radii based on a NACA 0012 airfoil. Subsequently, the Reynolds-averaged Navier–Stokes (RANS) method is employed to simulate the aerodynamic characteristics of static airfoils, while the improved delayed detached-eddy simulation (IDDES) method is employed for pitching airfoils. The effectiveness and accuracy of the computational fluid dynamics (CFD) methods are demonstrated through favorable agreement between the numerical and experimental results. Finally, both the static and dynamic aerodynamic characteristics are simulated and analyzed for the airfoils with varying leading edge radii. Comparative analyses indicate that at low Mach numbers, the high adverse pressure gradient near the leading edge is the primary cause of leading edge separation and stall. A larger leading edge radius helps to reduce the suction pressure peak and adverse pressure gradients, thus delaying the leading edge separation and stall of airfoil. At high Mach numbers, the leading edge separation and stall are mainly induced by the shock wave. Variations in leading edge radius have minimal impacts on the high adverse pressure gradient induced by the shock wave, thus making the stall characteristics of airfoils almost unaffected at high Mach numbers.

Simulation and Experimental Study on the Effect of Edge Radius on the Cutting Condition of Carbide Inserts

Carbide tools are extensively used in the automotive, aerospace, and marine industries. However, an unsuitable tool-edge treatment can affect the cutting performance of carbide tools. In the tool-cutting process, the cutting edge radius is one of the major factors that affect the cutting force, temperature, and quality. In this study, a cutting simulation model of carbide inserts was used to analyze the effect of the cutting edge radius on the cutting performance. The cutting edge radii of the inserts were prepared using shear-thickening polishing methods, followed by cutting experiments. The accuracy of the cutting simulation model was verified through cutting experiments. The simulation results showed that under low-speed cutting conditions, the cutting force and temperature tended to increase with an increase in the cutting edge radius, and the cutting temperature was less affected by the cutting edge radius. The results of the cutting force and cutting temperature obtained from the experiment and simulation were consistent; therefore, the cutting simulation model was verified to be reliable. The results indicate that modeling cutting simulation is a promising research method for predicting the cutting performance of tools.

Material deformation mechanism of lamellar twined high–entropy alloys during machining

The effects of sample structure and tool geometry are studied under cutting simulation to verify the deformation, removal mechanisms, and subsurface defection of lamellar twined CoCuFeNiPd alloys. These findings suggest that the twin boundary spacing (TBS) and twin inclination angle (β) are the main determinants of surface wear characteristics and cutting-induced surface harm. The maximum cutting force achieved with TBS = 8a and β = 90°. The high friction coefficient with the sample has TBS = 8a and β = 90°, showing that the tool’s moving in the substrate is strongly restricted. Furthermore, the surface topography is not sensitive to the TBS and β. The best-machined surface is achieved with TBS = 3a and 4a under twin inclinations of 0° and 30°. The effect of edge radius (R), rake angle (γ), and clearance angle (α) on the deformation behavior is examined. The negative of γ, small α, or larger R results in a higher cutting force, a worse subsurface, and a lower cutting pile-up height. With a positive γ, a large α or small R has a larger average friction coefficient, which implies a higher resistance rate. The tool with a smaller R or positive γ can improve the machined surface’s smoothness.

Effects of Cutting Edge Radius on the Surface Integrity of Milled Ti6Al4V Alloy

Effects of Cutting Edge Radius on the Surface Integrity of Milled Ti6Al4V Alloy

Effect of edge radius on forces, tool wear and surface integrity under edge radius dominated tool-chip contact conditions

Cutting-edge micro-geometry is a crucial factor influencing chip formation and tool performance. This paper investigates the effects of varying cutting edge radius (36–70 µm) on machinability and chip morphology during finish turning Ti6Al4V. An increase in edge radius decreases the cutting to thrust force ratio and produces lower chip thickness due to the increase in plowing zone depth. The machining temperature for the 48 and 52 µm edge radius tools is lower compared to all other tools. At the initial stage, the edge prepared tools exhibit larger flank wear, whereas subsequent flank wears progression is slower for the prepared tools as compared to the sharp tool. BUE and premature chipping is reduced for larger edge radius tool due to better edge stability provided by cutting edge preparation. Beyond the 59 µm edge radius, the process force, machining temperature, tool wear, and surface roughness increased steeply due to the increase in the size of the plowing zone. In addition to cutting force and machining temperature data, surface roughness, tool wear measurements and XRD analysis show that a radius range of 50–55 µm results in optimum performance for finish turning Ti6Al4V.

A Novel 2D Micromilling FEM simulation strategy to optimize the flow stress law of IN625

The products miniaturization tendency of the last years led to an acceleration of micromilling process development. Considering the high-quality requirements, a deep knowledge of this operation, concerning ploughing-shearing transition, tool run-out, and tool edge radius effects, is mandatory, especially when machining difficult-to-cut materials. For this reason, this paper introduces a novel 2D micromachining Finite Element Method simulation strategy for micromilling forces evaluation, when cutting IN625. The major output of this technique consists in the computation of an optimized flow stress law, suitable for the simulation of high-speed machining. Particle Swarm Optimization method was employed for optimizing the flow stress parameters by comparing the cutting force predicted by an analytical model previously calibrated on experimental data, providing good agreement. This strategy permits the micromilling process predictive analysis, avoiding costly optimization experimental tests.

An Investigation of Punch Radius and Clearance Effects on the Sheet Metal Blanking Process

In this study, the effects of punch edge radius and blanking clearance on product quality and blanking process in blanking of AISI 304 stainless steel sheet were investigated by using the fi-nite element analysis method. The blanking analyzes were performed at four different punch tip radii (0.01, 0.25, 0.5, 1 mm) and three different blanking clearance (1 %, 5%, 10%). As a result of the analysis, rollover, burr length increased, smooth sheared / fractured surface ratio and blanking force decreased with the increase in blanking clearance. Depending on the increase in the amount of punch tip radius, the blanking force, and burr length also increased, and the smooth sheared / fractured surface ratio decreased compared to the blanking process with flat punches.

Generic Cutting Force Modeling with Comprehensively Considering Tool Edge Radius, Tool Flank Wear and Tool Runout in Micro-End Milling.

Accurate cutting force prediction is crucial in improving machining precision and surface quality in the micro-milling process, in which tool wear and runout are essential factors. A generic analytic cutting force model considering the effect of tool edge radius on tool flank wear and tool runout in the micro-end milling process is proposed. Based on the analytic modeling of the cutting part of the cutting edge in the end face of the micro-end mill bottom, the actual radius model of the worn tool is established, considering the tool edge radius and tool flank wear. The tool edge radius, tool wear, tool runout, trochoidal trajectories of the current cutting edge, and all cutting edges in the previous cycle are comprehensively considered in the instantaneous uncut chip thickness calculation and the cutter-workpiece engagement determination. The cutting force coefficient model including tool wear is established. A series of milling experiments are performed to verify the accuracy and effectiveness of the proposed cutting force model. The results show that the predicted cutting forces are in good agreement with the experimental cutting forces, and it is necessary to consider tool wear in the micro-milling force modeling. The results indicate that tool wear has a significant influence on the cutting forces and cutting force coefficients in the three directions, and the influences of tool wear on the axial cutting force and axial force coefficient are the largest, respectively. The proposed cutting force model can contribute to real-time machining process monitoring, cutting parameters optimization and ensuring machining quality.

Effects of Cutting Edge Radius on Surface Integrity in Machining of Nickel-Based Cast Superalloy: An In Situ Imaging Approach

Abstract Cutting edge radius is a crucial factor affecting surface integrity during metal machining, which determines product performance. However, the exact mechanism of how the cutting edge radius affects machined surface has not yet been understood, especially lacking in situ evidence during the material removal process. In this article, effects of cutting edge radius on surface roughness, subsurface deformation, and work hardening of nickel-based cast superalloy are studied through an in situ imaging approach. Based on continuous high-speed filming and digital imaging correlation (DIC) techniques, detailed chip formation and quantitative subsurface plastic deformation under various cutting edge radii are analyzed, and the formation of built-up edge (BUE) is observed when using a large edge radius. Furthermore, when the cutting edge radius is greater than the uncut chip thickness (h), the thickness of plastic deformation increases dramatically. On the other hand, the machined surface roughness can be improved when the cutting edge radius is between 30% and 60% of h. The sharp cutting tools or the cutting edge radius higher than 60% of h result in a poor surface quality on the machined surface during nickel-based cast superalloy machining. The effects of cutting edge radius on machined surface generation are systematically categorized as cutting with chipping, cutting with significant plowing, and cutting with plowing accompanied by BUE formation.

Numerical predictions of orthogonal cutting–induced residual stress of super alloy Inconel 718 considering dynamic recrystallization

Manufacturing processes, such as machining, can produce residual stresses in products. Residual stress and its distribution can be the main factor influencing the fatigue life of machined components and has already been the subject of many experimental and numerical studies. The high-temperature condition, as a result of machining, makes a change in the microstructural properties of the material and consequently affect the mechanical properties of the workpiece. A major metal component of aircraft structure and engine components is nickel-based alloys due to their resistance to heat, corrosion, thermal fatigue, thermal shock, creep, and erosion. When these critical structural components in the aerospace industry are manufactured with the objective to reach high-reliability levels, surface integrity is one of the most relevant parameters used for evaluating the quality of finish-machined surfaces. The residual stresses and surface alterations including white layer, depth of work hardening, micro-cracks, and oxidation induced by machining of nickel-based alloys are extremely critical due to safety and sustainability concerns. Integrated Computational Materials Engineering (ICME) links physics-based models to predict the performance of materials based on their processing history. The Johnson–Mehl–Avrami-Kolmogrov (JMAK) model is used to develop a microstructure-based modeling approach that takes into account dynamic recrystallization (DRX) that causes grain size changes. Allied with that, a grain size parameter on the flow stress behavior of the material is considered by adding a grain size-dependent term to the traditional Johnson–Cook (JC) model as a novel framework. The impact of the simulation of the orthogonal cutting process is implemented in a finite element method (FEM) model–based commercial software, ABAQUS-explicit, with a coupled Euler-Lagrangian (CEL) approach. By relying on the VUHARD user subroutine capabilities with Fortran language, ABAQUS-explicit can be steered to model the material behavior considering the term of DRX. The forecast capability of the developed model is assessed by comparison of the results by changing the depth of cut and cutting edge radius effect on the residual stress. Then, the correlation between the grain size evolution and temperature distribution by changing the cutting velocity is investigated.

Study of the Influence of Cutting Edge on Micro Cutting of Hardened Steel Using FE and SPH Modeling.

Micromachining allows the production of micro-components with complex geometries in various materials. However, it presents several scientific issues due to scale reduction compared to conventional machining. These issues are called size effects. At this level, micromachining experiments raise technical difficulties and significant costs. In this context, numerical modeling is widely used in order to study these different size effects. This article presents four different numerical models of micro-cutting of hardened steel, a Smooth Particle Hydrodynamics (SPH) model and three finite element (FE) models using three different formulations: Lagrangian, Arbitrary Eulerian–Lagrangian (ALE) and Coupled Eulerian–Lagrangian (CEL). The objective is to study the effect of tool edge radius on the micro-cutting process through the evolution of cutting forces, chip morphology and stress distribution in different areas and to compare the relevance of the different models. First, results obtained from two models using FE (Lagrangian) and SPH method were compared with experimental data obtained in previous work. It shows that the different numerical methods are relevant for studying geometrical size effects because cutting force and stress distribution correlate with experimental data. However, they present limits due to the calculation approaches. For a second time, this paper presents a comparison between the four different numerical models cited previously in order to choose which method of modeling can present the micro-cutting process.

Numerical investigation of sequential cuts residual stress considering tool edge radius in machining of AISI 304 stainless steel

Residual stress affects component performance, and the existence of pre-stress changes the residual stress of machined surfaces as well, emphasizing the importance of studying the evolution of residual stress in sequential cutting. This paper reports a numerical investigation of the machining-induced residual stress profile of sequential cuts for orthogonal cutting of AISI 304, considering the effects of edge radius and cutting depth. A Coupled Eulerian-Lagrangian (CEL) model is employed for the first time to stably simulate the evolution of residual stress of multiple sequential cuts. The effectiveness of the proposed method is verified by comparing the chip formation and surface residual stress between simulated and experimental results. The cutting force and cutting temperature, as well as mechanical and thermal loads, are extracted to explain the generation and evolution of residual stress in sequential cutting. It is found that the residual stress on the machined surfaces will decrease during sequential cutting, and a stable value can be reached after approximately six sequential cuts. With the progress of sequential cutting, a larger honed tool edge radius and cutting depth will lead to a slower reduction of residual stress.

Numerical investigations on residual stresses in orthogonal cutting of Ti-6A1-4V

Titanium is widely employed in aerospace space, where the surface integrity plays an important role in part quality. This paper presents the numerical and experimental results of residual stress when machining Titanium based on a CEL (Coupled Eulerian-Lagrangian) method. The performance of proposed model is compared with LAG (Lagrangian) and ALE (Arbitrary Lagrangian-Eulerian) methods regarding segment chip formation and residual stress. The correctness of simulation results is validated by orthogonal cutting experiments of Ti-6Al-4V as well as the experimental data given in recent published literature. The effects of uncut chip thickness, cutting velocity and edge radius on residual stress are discussed through simulation results.

Cutting edge radius effect on the surface integrity of orthogonal turned aluminium alloy Al6082 with different initial microstructure

In the present study, the combined effect of initial microstructure and relative tool sharpness (RTS) on the surface integrity of aluminium(Al6082) alloy has been investigated. Orthogonal turning is carried out on as-received and heat-treated specimen with group of edge radiused tools. Surface roughness and micro hardness have been evaluated with respect to number of turns for varying RTS value. Results indicate that the workpiece material adhesion on the tool has significantly influenced the surface roughness. In addition, below the critical RTS, the surface integrity is greatly influenced by the grain size of the material.

The effects of edge radius on wind tunnel tests of low-rise buildings

Models used for the wind tunnel testing of structures are commonly fabricated using additive manufacturing techniques, such as 3D printing; however, the corners of the models can sometimes be rounded with some radius of curvature R , rather than be perfectly sharp. Should the edge curvature of these models be too large, the aerodynamics of these models can be significantly altered leading to unrealistic wind load estimations. To address this issue, a series of wind tunnel tests were conducted on a generic low-rise building model with varying edge radii to: (1) determine the effect of edge curvature on surface pressures and (2) determine a limit on edge radii of wind tunnel models, above which, the aerodynamics of the model is no longer representative of that around the full-scale building. It was found that increasing edge radius produces a continual change in pressure fields within the vicinity of separation bubbles and conical vortices (depending on wind direction). Considering the current experimental setup, changes in mean pressure fields exceed measurement uncertainty when the edge radius R / H > ~ 1.3%, where H is building height. The subsequent changes in pressure fields also lead to discrepancies in area-averaged pressures, however, the effects appear to be limited to small areas near building edges whose surface areas are below about 2 m 2 for a low-rise building with a roof height of 4 m and plan dimensions of 10 m × 15 m . • Effects of edge curvature on low-rise building wind tunnel models were examined • Edge curvature effects of are limited primarily to regions of separated flow • Edge curvature effects vary continuously with radius of curvature • It is recommended that the radius of curvature should not exceed 1.3% of height

A strong basis for friction as the origin of size effect in cutting of metals

A study has been made of the phenomenon of size effect in cutting of metals, namely increase in the specific energy with decreasing chip thickness, in the absence of edge radius effects and under ideal two-dimensional cutting conditions. Freshly cleaved glass knives are used to achieve cutting edges that are sharp on an atomic level. An instrumented ultramicrotomy apparatus is described in which it is possible to achieve two-dimensional orthogonal cutting at small cutting depths in the range of 100 nm to 3 micrometers. Based on observations with three metals (aluminum, copper and zinc), new evidence is presented in support of tool-chip friction as the primary source of the size effect. It is shown that size effect arises as a result of non-proportional decrease of the friction component with the underlying length scale. Calculation of the shear flow stress during cutting showed that this was approximately constant for a given material, independent of the depth of cut. Size dependence of tool-chip friction and contact size is interpreted in terms of the junction growth and adhesion models. Cutting experiments are also carried out with tools covered with solid and liquid contaminants. These results show that contaminant films effectively diminish adhesion and lead to a drastic reduction in the size effect, suggesting practical benefits for industrial manufacturing processes.

An analytical model for micro-cutting considering the cutting tool edge radius effect and material separation

Severe plastic deformation occurs in micro metal cutting process; meanwhile, new surfaces are generated due to the material separation caused by ductile fracture. The energy required for the formation of the new surfaces is of kJ/m2, which should not be neglected in the analysis of micro-cutting. In this work, an analytical model is developed focusing on the analyses of the micro metal cutting process with no stable built-up edge, in which the effects of both edge radius and material separation are taken into account. The cutting tool edge geometry is simplified with the effective rake angle. On the basis of slip-line field theory, the equation of the cutting power is derived. Applying the minimum energy principle, two nonlinear equations are obtained, through which the shear angle and the minimum chip thickness can be estimated simultaneously. The model is examined through the experiments; the investigations show that the calculation results of cutting force and shear angle agreed with the experimental measurements very well. The effects of fracture toughness, shear yield stress, and friction angle to the micro-cutting process are investigated. The numerical results show that the friction angle affects the cutting force and the shear angle greatly.

A novel contact area based analysis to study the thermo-mechanical effect of cutting edge radius using numerical and multi-sensor experimental investigation in turning

Abstract The micro-geometry of the cutting tool significantly affects the process forces, thermal load, tool wear, and quality of the finished surface and chip characteristics. The effect of edge radius on the thermo-mechanical load for varying uncut chip thickness is studied during turning AISI 4340. A multi-sensor approach is used to measure the temperature at the flank face, the average temperature of the chip in the cutting zone and also at the free surface of the chip simultaneously by using a thermocouple, a thermal camera and a pyrometer respectively. A novel tool-chip contact area based analysis is used to delineate the effect of hone radius and nose radius separately. The major and minor cutting edge contact areas along the hone region are found to play a key role in influencing the process forces and temperature at different feeds. FEM simulations are conducted to study the effect caused by edge radius on the material flow in the stagnation and ploughing zones. Also, a linear regression analysis is carried out to predict the ideal cutting edge radius for different feeds used in this study − 0.1 mm/rev − 18 μm; 0.24 mm/rev − 33 μm; and 0.41 mm/rev − 43 μm. The results from this experimentation could be used by researchers to validate their temperature models and develop more accurate temperature maps of the tool.

FE analysis on the association between tool edge radius and thermal-mechanical load in machining Inconel 718

The cutting edge geometry has a significant influence on thermal-mechanical loads and the quality of machined surface in machining operations. In this study, a joint numerical and experimental investigation was conducted to study the effects of tool edge radius on process variables (tool temperatures, force components, stresses) and process dynamics in orthogonal machining Inconel 718. The numerical model was implemented based on Coupled Eulerian-Lagrangian (CEL) formulation, in which the tool is regarded as elastic, making it possible to realise the fluctuation of the tool tip. The results show that the temperature at the tool tip is more sensitive to the change of edge radius than the maximum temperature at the tool-chip interface. The force components acting on rake face and flank face increase with increasing edge radius due to more negative effective rake angle and increasing ploughing depth respectively. Besides, the generated chip tends to be more segmented with increase of edge radius, causing severer fluctuation of forces and tool tip displacement. It was also found that a larger edge radius leads to a smaller uncut chip thickness and a poor surface roughness.