The Experts below are selected from a list of 231 Experts worldwide ranked by ideXlab platform
Karali Patra - One of the best experts on this subject based on the ideXlab platform.
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influences of tialn coating and limiting angles of flutes on prediction of cutting forces and dynamic stability in micro milling of die steel p 20
Journal of Materials Processing Technology, 2020Co-Authors: Priyabrata Sahoo, Karali Patra, Vishnu Kumar Singh, Munish Kumar Gupta, Qinghua Song, Mozammel Mia, Danil Yurievich PimenovAbstract:Abstract Due to a lower stiffness value, the micro tool is prone to deflection that ultimately gives rise to chatter, tool wear, catastrophic tool breakage and worse surface generation. Especially, during micro milling of hard materials, these issues become more critical. To encounter these impediments, a hard coating with lower coefficient of friction of the cutting tool can be regarded as a viable solution to improve its tooling performance by reducing the tool wear and tool breakage. However, the prediction of cutting forces and stability limits, considered essential to enhance the tooling performance in micro milling using coated tool, has not been reported so far. This article proposes an analytical approach for the prediction of cutting forces in both shearing and ploughing dominant regions by combining FEM simulation and mechanistic modelling by the consideration of tool run out, Minimum Chip Thickness (MCT), elastic recovery, ploughing area and limiting angle (entry and exit angles) of the flutes for the combination of TiAlN coated tool and P-20 steel workpiece. Furthermore, the modelling of dynamic stability in frequency domain has been instituted by incorporating the force coefficient obtained from FEM simulation results and the exact entry and exit angles of the flutes which change due to tool run out. Finally, both proposed models have been verified through experimental results, and the influence of coating material has been shown to be viable by enhancing the stability limits and by reducing the prediction error of cutting forces.
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a hybrid modelling approach towards prediction of cutting forces in micro end milling of ti 6al 4v titanium alloy
International Journal of Mechanical Sciences, 2019Co-Authors: Priyabrata Sahoo, Tej Pratap, Karali PatraAbstract:Abstract Prediction of cutting forces in micro end milling is a key aspect for both quality of machining surface and safety of the tool. Further, estimation of cutting coefficients is very much crucial for precise prediction of actual cutting forces. In general, these are obtained by cutting calibration experiments which consume lot of energy and resources. So, to overcome such impediments and to accomplish a purely analytical modelling, this study proposes a hybrid approach for prediction of cutting forces in micro end milling of titanium alloy Ti-6Al-4V. Preliminarily, cutting force coefficients have been evaluated by using finite element simulation considering orthogonal cutting of Ti-6Al-4V using round edge carbide tool. Johnson-Cook material model has been considered for the flow stress calculation in finite element (FE) analysis. Cutting force coefficients have been extracted by simulating the cutting process for a series of undeformed Chip Thickness (UCT). Finally, mechanistic cutting force model is developed by integrating the small elemental cutting force by incorporating the extracted cutting force coefficients. An improved UCT algorithm which can be used for both lower and higher value of tool run out efficiently is implemented by considering trochoidal trajectory of tool centre, tool run out, Minimum Chip Thickness and elastic recovery and trajectories of all the preceding teeth for one complete revolution of the tool. To validate the proposed model, cutting force experiments have been carried out and results are compared. A comparative analysis shows a very good agreement between predicted and experimental cutting forces.
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Mechanistic modeling of cutting forces in micro-end-milling considering tool run out, Minimum Chip Thickness and tooth overlapping effects
Machining Science and Technology, 2018Co-Authors: Priyabrata Sahoo, Karali PatraAbstract:AbstractThis work proposed an improved mechanistic model for prediction of cutting forces in micro-milling process. The combined influences of tool run out, trochoidal trajectory of the tool center, overlapping of tooth, edge radius and Minimum Chip Thickness are incorporated in this model to realize the exact cutting phenomenon. Moreover, an improved undeformed Chip Thickness algorithm has been presented by considering tool run out, Minimum Chip Thickness and trajectory of all passing teeth for one complete revolution of the tool instead of only the current tooth trajectory. For estimation of tool run out, a model based on the geometry of the two fluted end mill cutter has been developed. Effects of trochoidal trajectory of the tool center and tool run out are found to be significant as each tooth has a different Chip load. Further, the effect of Minimum Chip Thickness is found to be significant at lower feed value. The proposed model has been validated by micro-milling experiments on Ti6Al4V-titanium al...
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mechanistic modeling of micro drilling cutting forces
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Ravi Shankar Anand, Markus Steiner, Karali Patra, Dirk BiermannAbstract:This paper presents a mechanistic model for micro-drilling cutting forces that includes the cutting edge radius and the Minimum Chip Thickness size effects. The proposed model considers three different cutting regions, i.e., ploughing-dominant, transition, and shearing-dominant, based on these size effects. Specific normal force and specific friction force coefficients have been determined through model calibration using micro-drilling experimental results. Model is validated with micro-drilling experimental results of different cutting conditions and of different machining environments. Comparisons of model simulated and experimental results show that ploughing force contributions are significant, especially at low feed rates. The proposed model has also been applied to characterize size effects in micro-drilling.
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extracting specific cutting force coefficients in micro drilling with tool edge radius effects
Applied Mechanics and Materials, 2015Co-Authors: Ravi Shankar Anand, Karali PatraAbstract:This article introduces a methodology for extracting specific cutting force coefficients by performing micro drilling experiments with tool edge radius effect.Tool edge radius mainly affects the effective rake angle that varies according to undeformed Chip Thickness. Ploughing effect is also considered for undeformed Chip Thickness lower than the Minimum Chip Thickness. In this work specific normal and frictional cutting coefficients for both ploughing and shearing are determined from mechanistic approach of fitting experimental specific thrust forces of the micro drilling process. The variations of these cutting coefficients with respect to cutting speedand feed are presented. Finally these coefficients have been applied to the mechanistic model to predict thrust force in micro drilling. The predicted thrust force values at different feed show good agreement with the experimental results.
Priyabrata Sahoo - One of the best experts on this subject based on the ideXlab platform.
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influences of tialn coating and limiting angles of flutes on prediction of cutting forces and dynamic stability in micro milling of die steel p 20
Journal of Materials Processing Technology, 2020Co-Authors: Priyabrata Sahoo, Karali Patra, Vishnu Kumar Singh, Munish Kumar Gupta, Qinghua Song, Mozammel Mia, Danil Yurievich PimenovAbstract:Abstract Due to a lower stiffness value, the micro tool is prone to deflection that ultimately gives rise to chatter, tool wear, catastrophic tool breakage and worse surface generation. Especially, during micro milling of hard materials, these issues become more critical. To encounter these impediments, a hard coating with lower coefficient of friction of the cutting tool can be regarded as a viable solution to improve its tooling performance by reducing the tool wear and tool breakage. However, the prediction of cutting forces and stability limits, considered essential to enhance the tooling performance in micro milling using coated tool, has not been reported so far. This article proposes an analytical approach for the prediction of cutting forces in both shearing and ploughing dominant regions by combining FEM simulation and mechanistic modelling by the consideration of tool run out, Minimum Chip Thickness (MCT), elastic recovery, ploughing area and limiting angle (entry and exit angles) of the flutes for the combination of TiAlN coated tool and P-20 steel workpiece. Furthermore, the modelling of dynamic stability in frequency domain has been instituted by incorporating the force coefficient obtained from FEM simulation results and the exact entry and exit angles of the flutes which change due to tool run out. Finally, both proposed models have been verified through experimental results, and the influence of coating material has been shown to be viable by enhancing the stability limits and by reducing the prediction error of cutting forces.
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a hybrid modelling approach towards prediction of cutting forces in micro end milling of ti 6al 4v titanium alloy
International Journal of Mechanical Sciences, 2019Co-Authors: Priyabrata Sahoo, Tej Pratap, Karali PatraAbstract:Abstract Prediction of cutting forces in micro end milling is a key aspect for both quality of machining surface and safety of the tool. Further, estimation of cutting coefficients is very much crucial for precise prediction of actual cutting forces. In general, these are obtained by cutting calibration experiments which consume lot of energy and resources. So, to overcome such impediments and to accomplish a purely analytical modelling, this study proposes a hybrid approach for prediction of cutting forces in micro end milling of titanium alloy Ti-6Al-4V. Preliminarily, cutting force coefficients have been evaluated by using finite element simulation considering orthogonal cutting of Ti-6Al-4V using round edge carbide tool. Johnson-Cook material model has been considered for the flow stress calculation in finite element (FE) analysis. Cutting force coefficients have been extracted by simulating the cutting process for a series of undeformed Chip Thickness (UCT). Finally, mechanistic cutting force model is developed by integrating the small elemental cutting force by incorporating the extracted cutting force coefficients. An improved UCT algorithm which can be used for both lower and higher value of tool run out efficiently is implemented by considering trochoidal trajectory of tool centre, tool run out, Minimum Chip Thickness and elastic recovery and trajectories of all the preceding teeth for one complete revolution of the tool. To validate the proposed model, cutting force experiments have been carried out and results are compared. A comparative analysis shows a very good agreement between predicted and experimental cutting forces.
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Mechanistic modeling of cutting forces in micro-end-milling considering tool run out, Minimum Chip Thickness and tooth overlapping effects
Machining Science and Technology, 2018Co-Authors: Priyabrata Sahoo, Karali PatraAbstract:AbstractThis work proposed an improved mechanistic model for prediction of cutting forces in micro-milling process. The combined influences of tool run out, trochoidal trajectory of the tool center, overlapping of tooth, edge radius and Minimum Chip Thickness are incorporated in this model to realize the exact cutting phenomenon. Moreover, an improved undeformed Chip Thickness algorithm has been presented by considering tool run out, Minimum Chip Thickness and trajectory of all passing teeth for one complete revolution of the tool instead of only the current tooth trajectory. For estimation of tool run out, a model based on the geometry of the two fluted end mill cutter has been developed. Effects of trochoidal trajectory of the tool center and tool run out are found to be significant as each tooth has a different Chip load. Further, the effect of Minimum Chip Thickness is found to be significant at lower feed value. The proposed model has been validated by micro-milling experiments on Ti6Al4V-titanium al...
Kornel F. Ehmann - One of the best experts on this subject based on the ideXlab platform.
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Surface roughness modeling in micro end-milling
The International Journal of Advanced Manufacturing Technology, 2018Co-Authors: Yanjie Yuan, Xiubing Jing, Kornel F. EhmannAbstract:Micro end-milling is widely used in many industries to produce micro products with complex 3D shapes. The accurate modeling and prediction of surface roughness are important for evaluating the productivity of the machine tools and the surface quality of the machined parts. This paper presents an accurate surface roughness model based on the kinematics of cutting process and tool geometry by considering the effects of tool run-out and Minimum Chip Thickness. The proposed surface roughness model is validated by micro end-milling experiments with the miniaturized machine tool. The results show that the proposed surface roughness model can accurately predict both the trends and magnitude of the surface roughness in micro end-milling.
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modeling of cutting forces in micro end milling
Journal of Manufacturing Processes, 2018Co-Authors: Yanjie Yuan, Xiubing Jing, Kornel F. Ehmann, Jian Cao, Dawei ZhangAbstract:Abstract Accurate modeling and prediction of cutting forces are important for process planning and optimization in micro end-milling process. In order to exactly predict the cutting forces, an innovative uncut Chip Thickness algorithm is proposed by considering the combination of the exact trochoidal trajectory of the tool tip and the cutting trajectory of all previously passing teeth, tool run-out, Minimum Chip Thickness and the material’s elastic recovery. The proposed uncut Chip Thickness algorithm also considers the variation of the entry and exit angles caused by tool run-out. To determine the cutting force coefficients, a finite element model (FEM) of orthogonal micro-cutting that considers strain hardening, strain rate sensitivity, thermal softening behavior, and temperature-dependent flow has been established. Based on the results from FEM analysis, the cutting force coefficients are identified and represented by a nonlinear equation of the uncut Chip Thickness, cutting edge radius and cutting velocity. The identified cutting force coefficients are integrated into a mechanistic cutting force model and used to simulate micro end-milling forces. The simulation results show a very satisfactory agreement with the experimental results.
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an analysis of the surface generation mechanics of the elliptical vibration texturing process
International Journal of Machine Tools & Manufacture, 2013Co-Authors: Kornel F. EhmannAbstract:Abstract The elliptical vibration texturing process is a vibration assisted machining method for the fast generation of micro structured surfaces. It adds a higher order motion component to the cutting tool that leads to periodic changes in the cutting depth during the machining process. This results in the creation of micro-dimples on the machined surface, whose shape is a function of the tool geometry and trajectory. This paper studies the surface generation mechanics of the elliptical vibration texturing process through experimentation and modeling. A surface generation algorithm is presented for this newly developed process. The model fully describes the motion and the 3D geometry of the cutting tool including its rake face, flank face, and the cutting edge, since all these tool features influence the topography of the generated surface. Since the process takes place in the micro/meso-scale cutting regime, the model includes the Minimum Chip Thickness and elastic recovery effects. The experimental results are shown to validate the simulation model. The simulation model is used to characterize the influences of the process parameters on the texture patterns. The effects of the tool geometry on the process, including the cutting edge radius, are also analyzed.
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a mechanistic model of cutting forces in micro end milling with cutting condition independent cutting force coefficients
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2008Co-Authors: Han Ul Lee, Dongwoo Cho, Kornel F. EhmannAbstract:Complex three-dimensional miniature components are needed in a wide range of industrial applications from aerospace to biomedicine. Such products can be effectively produced by micro-end-milling processes that are capable of accurately producing high aspect ratio features and parts. This paper presents a mechanistic cutting force model for the precise prediction of the cutting forces in micro-end-milling under various cutting conditions. In order to account for the actual physical phenomena at the edge of the tool, the components of the cutting force vector are determined based on the newly introduced concept of the partial effective rake angle. The proposed model also uses instantaneous cutting force coefficients that are independent of the end-milling cutting conditions. These cutting force coefficients, determined from measured cutting forces, reflect the influence of the majority of cutting mechanisms involved in micro-end-milling including the Minimum Chip-Thickness effect. The comparison of the predicted and measured cutting forces has shown that the proposed method provides very accurate results.
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the mechanics of machining at the microscale assessment of the current state of the science
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2004Co-Authors: Xinyu Liu, Richard E. Devor, Shiv Gopal Kapoor, Kornel F. EhmannAbstract:This paper provides a comprehensive review of the literature, mostly of the last 10-15 years, that is enhancing our understanding of the mechanics of the rapidly growing field of micromachining. The paper focuses on the mechanics of the process, discussing both experimental and modeling studies, and includes some work that, while not directly focused on micromachining, provides important insights to the field. Experimental work includes the size effect and Minimum Chip Thickness effect, elastic-plastic deformation, and microstructure effects in micromachining. Modeling studies include molecular dynamics methods, finite element methods, mechanistic modeling work, and the emerging field of multiscale modeling. Some comments on future needs and directions are also offered.
Tej Pratap - One of the best experts on this subject based on the ideXlab platform.
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a hybrid modelling approach towards prediction of cutting forces in micro end milling of ti 6al 4v titanium alloy
International Journal of Mechanical Sciences, 2019Co-Authors: Priyabrata Sahoo, Tej Pratap, Karali PatraAbstract:Abstract Prediction of cutting forces in micro end milling is a key aspect for both quality of machining surface and safety of the tool. Further, estimation of cutting coefficients is very much crucial for precise prediction of actual cutting forces. In general, these are obtained by cutting calibration experiments which consume lot of energy and resources. So, to overcome such impediments and to accomplish a purely analytical modelling, this study proposes a hybrid approach for prediction of cutting forces in micro end milling of titanium alloy Ti-6Al-4V. Preliminarily, cutting force coefficients have been evaluated by using finite element simulation considering orthogonal cutting of Ti-6Al-4V using round edge carbide tool. Johnson-Cook material model has been considered for the flow stress calculation in finite element (FE) analysis. Cutting force coefficients have been extracted by simulating the cutting process for a series of undeformed Chip Thickness (UCT). Finally, mechanistic cutting force model is developed by integrating the small elemental cutting force by incorporating the extracted cutting force coefficients. An improved UCT algorithm which can be used for both lower and higher value of tool run out efficiently is implemented by considering trochoidal trajectory of tool centre, tool run out, Minimum Chip Thickness and elastic recovery and trajectories of all the preceding teeth for one complete revolution of the tool. To validate the proposed model, cutting force experiments have been carried out and results are compared. A comparative analysis shows a very good agreement between predicted and experimental cutting forces.
Xinmin Lai - One of the best experts on this subject based on the ideXlab platform.
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modelling and experimental analysis of the effects of tool wear Minimum Chip Thickness and micro tool geometry on the surface roughness in micro end milling
Journal of Micromechanics and Microengineering, 2008Co-Authors: Xinmin Lai, Jie FengAbstract:Tool wear, Minimum Chip Thickness and micro tool geometry are found to have a significant influence on the surface roughness through experimental analysis of the micro-end-milling process. To address these issues, a surface roughness model is developed and validated in this present work. Firstly, experimental analysis for the tool wear and surface roughness was performed based on the micro-end-milling experiments of OFHC Copper by using 0.1 mm diameter micro endmills with a miniaturized machine tool. The cutting velocity and material removal volume are found to have a great effect on the tool wear, which will in turn affect the surface roughness significantly. Then, a trajectory-based surface roughness model for micro-end-milling is proposed and proven capable of capturing the Minimum Chip Thickness, micro tool geometry and process parameters. Finally, based on this model, a surface roughness model with tool wear effect is developed by taking the material removal volume and cutting velocity into account and is experimentally validated. This model accurately predicts the surface roughness variation with tool wear progress and provides the means for further process design and optimization studies of the micro-end-milling process.
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Modelling and analysis of micro scale milling considering size effect, micro cutter edge radius and Minimum Chip Thickness
International Journal of Machine Tools & Manufacture, 2007Co-Authors: Xinmin Lai, Zhongqin LinAbstract:Abstract This paper presents mechanisms studies of micro scale milling operation focusing on its characteristics, size effect, micro cutter edge radius and Minimum Chip Thickness. Firstly, a modified Johnson–Cook constitutive equation is formulated to model the material strengthening behaviours at micron level using strain gradient plasticity. A finite element model for micro scale orthogonal machining process is developed considering the material strengthening behaviours, micro cutter edge radius and fracture behaviour of the work material. Then, an analytical micro scale milling force model is developed based on the FE simulations using the cutting principles and the slip-line theory. Extensive experiments of OFHC copper micro scale milling using 0.1 mm diameter micro tool were performed with miniaturized machine tool, and good agreements were achieved between the predicted and the experimental results. Finally, Chip formation and size effect of micro scale milling are investigated using the proposed model, and the effects of material strengthening behaviours and Minimum Chip Thickness are discussed as well. Some research findings can be drawn: (1) from the Chip formation studies, Minimum Chip Thickness is proposed to be 0.25 times of cutter edge radius for OFHC copper when rake angle is 10° and the cutting edge radius is 2 μm; (2) material strengthening behaviours are found to be the main cause of the size effect of micro scale machining, and the proposed constitutive equation can be used to explain it accurately. (3) That the specific shear energy increases greatly when the uncut Chip Thickness is smaller than Minimum Chip Thickness is due to the ploughing phenomenon and the accumulation of the actual Chip Thickness.
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modeling of three dimensional cutting forces in micro end milling
Journal of Micromechanics and Microengineering, 2007Co-Authors: Xinmin LaiAbstract:A new nominal uncut Chip Thickness algorithm for micro-scale end-milling is proposed by considering the combination of an exact trochoidal trajectory of the tool tip and tool run-out, and then the actual uncut Chip Thickness may be obtained from a comparison between the current accumulative uncut Chip Thickness and the Minimum Chip Thickness. Due to the intermittency of the Chip formation, the milling process is divided into an elastic-plastic deformation regime and a Chip formation regime dominated by ploughing forces and shearing forces, respectively, and three-dimensional cutting forces are modeled according to different regimes. Based on the modeling and simulation technologies introduced, a simulation system for the prediction of three-dimensional cutting forces of a micro-scale end-milling process is developed. The simulation results show a very satisfactory agreement with those data from milling experiments.