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Jean-lou Lebrun - One of the best experts on this subject based on the ideXlab platform.
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An experimental study of the effect of high-pressure water jet assisted turning (HPWJAT) on the surface integrity
International Journal of Machine Tools and Manufacture, 2011Co-Authors: Malek Habak, Jean-lou LebrunAbstract:This study deals with the effect of High-Pressure Water Jet Assisted Turning (HPWJAT) of austenitic stainless steels on Chip shape and residual stresses. The machining of the austenitic stainless steels represents several difficulties. Recently, research has shown that the introduction of a high-pressure water jet into the gap between the tool and the Chip Interface is a very satisfactory method for machining applications. In this article, the effect of a high-pressure water jet, directed into the tool-Chip Interface, on Chip shapes breakage and surface integrity in face turning operations of AISI 316L steel has been investigated. Tests have been carried out with a standard cutting tool. The cutting speeds used were 80 and 150 m/min, with a constant feed rate of 0.1 mm/rev and a constant cutting depth of 1 mm. Three jet pressures were used: 20, 50 and 80 MPa. Residual stress profiles have been analysed using the X-ray diffraction method in both longitudinal and transversal directions. The results show that jet pressure and cutting parameters influence the residual stresses and the Chip shapes. Using a high-pressure jet, it is possible to create a well fragmented Chip in contrast to the continuous Chip formed using dry turning. It is also possible to control the Chip shape and increase tool life. When the jet pressure is increased the residual stress at the surface decreases; however it is increased by an increase in cutting speed. It can be concluded that surface residual stresses can be reduced by the introduction of a high-pressure water jet.
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residual stress in high pressure water jet assisted turning of austenitic stainless steel
Materials Science Forum, 2006Co-Authors: Malek Habak, Jean-lou Lebrun, Stefan Waldmann, Patrick Robert, Cyril FischerAbstract:In this paper, the effect of a high pressure water jet, directed into the tool Chip Interface, on surface residual stresses and Chip shape, in face turning of AISI 316L stainless steel has been investigated. Tests have been carried out with a standard cutting tool. This tool is not specifically meant for the machining of this type of material. The cutting speeds used were 80 m/min and 150 m/min, with a constant feed rate of 0.1 mm/rev and a constant cutting depth of 0.1 mm. Three jet pressures were used: 20, 50 and 80 MPa. Residual stress profiles have been analysed using the X-ray diffraction method in both longitudinal and transversal directions. The results show that by using a high pressure jet directed into the tool-Chip Interface, it is possible to create a well fragmented Chip in contrast to the continuous Chip formed using dry turning. It is also possible to control the Chip shape and increase tool life. When the jet pressure is increased the residual stress at the surface decreases however it is increased by an increase in cutting speed. It can be concluded that surface residual stresses can be reduced by the introduction of a high pressure water jet. A reduction in the residual stress value by about 20 to 40 % can be observed when using high pressure water jet assisted turning compared to dry turning. Also, it has been observed that the jet pressure does not have a great influence on the depth affected by residual stress and by hardening.
Malek Habak - One of the best experts on this subject based on the ideXlab platform.
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An experimental study of the effect of high-pressure water jet assisted turning (HPWJAT) on the surface integrity
International Journal of Machine Tools and Manufacture, 2011Co-Authors: Malek Habak, Jean-lou LebrunAbstract:This study deals with the effect of High-Pressure Water Jet Assisted Turning (HPWJAT) of austenitic stainless steels on Chip shape and residual stresses. The machining of the austenitic stainless steels represents several difficulties. Recently, research has shown that the introduction of a high-pressure water jet into the gap between the tool and the Chip Interface is a very satisfactory method for machining applications. In this article, the effect of a high-pressure water jet, directed into the tool-Chip Interface, on Chip shapes breakage and surface integrity in face turning operations of AISI 316L steel has been investigated. Tests have been carried out with a standard cutting tool. The cutting speeds used were 80 and 150 m/min, with a constant feed rate of 0.1 mm/rev and a constant cutting depth of 1 mm. Three jet pressures were used: 20, 50 and 80 MPa. Residual stress profiles have been analysed using the X-ray diffraction method in both longitudinal and transversal directions. The results show that jet pressure and cutting parameters influence the residual stresses and the Chip shapes. Using a high-pressure jet, it is possible to create a well fragmented Chip in contrast to the continuous Chip formed using dry turning. It is also possible to control the Chip shape and increase tool life. When the jet pressure is increased the residual stress at the surface decreases; however it is increased by an increase in cutting speed. It can be concluded that surface residual stresses can be reduced by the introduction of a high-pressure water jet.
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residual stress in high pressure water jet assisted turning of austenitic stainless steel
Materials Science Forum, 2006Co-Authors: Malek Habak, Jean-lou Lebrun, Stefan Waldmann, Patrick Robert, Cyril FischerAbstract:In this paper, the effect of a high pressure water jet, directed into the tool Chip Interface, on surface residual stresses and Chip shape, in face turning of AISI 316L stainless steel has been investigated. Tests have been carried out with a standard cutting tool. This tool is not specifically meant for the machining of this type of material. The cutting speeds used were 80 m/min and 150 m/min, with a constant feed rate of 0.1 mm/rev and a constant cutting depth of 0.1 mm. Three jet pressures were used: 20, 50 and 80 MPa. Residual stress profiles have been analysed using the X-ray diffraction method in both longitudinal and transversal directions. The results show that by using a high pressure jet directed into the tool-Chip Interface, it is possible to create a well fragmented Chip in contrast to the continuous Chip formed using dry turning. It is also possible to control the Chip shape and increase tool life. When the jet pressure is increased the residual stress at the surface decreases however it is increased by an increase in cutting speed. It can be concluded that surface residual stresses can be reduced by the introduction of a high pressure water jet. A reduction in the residual stress value by about 20 to 40 % can be observed when using high pressure water jet assisted turning compared to dry turning. Also, it has been observed that the jet pressure does not have a great influence on the depth affected by residual stress and by hardening.
Zhen Bing Hou - One of the best experts on this subject based on the ideXlab platform.
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thermal modeling of the metal cutting process part ii temperature rise distribution due to frictional heat source at the tool Chip Interface
International Journal of Mechanical Sciences, 2001Co-Authors: R Komanduri, Zhen Bing HouAbstract:Abstract Heat partition and the temperature rise distribution in the moving Chip as well as in the stationary tool due to frictional heat source at the Chip–tool Interface alone in metal cutting were determined analytically using functional analysis. An analytical model was developed that incorporates two modifications to the classical solutions of Jaeger's moving band (for the Chip) and stationary rectangular (for the tool) heat sources for application to metal cutting. It takes into account appropriate boundaries (besides the tool–Chip contact Interface) and considers non-uniform distribution of the heat partition fraction along the tool–Chip Interface for the purpose of matching the temperature distribution both on the Chip side and the tool side. Using the functional analysis approach, originally proposed by Chao and Trigger (Transactions of ASME, 1951; 73:57–68), a pair of functional expressions for the non-uniform heat partition fraction along the tool–Chip Interface — one for the moving band heat source (for the Chip side) and the other for the stationary rectangular heat source (for the tool side) were developed. Using this analysis, the temperature rise distribution in the Chip and the tool were determined for two cases of machining, namely, conventional machining of steel with a carbide tool at high Peclet number ( N Pe ≈5–20) and ultraprecision machining of aluminum with a single-crystal diamond tool at low Peclet number ( N Pe –0.5). The calculated temperature rise distribution curves on the two sides of the tool–Chip Interface are found to be well matched for both cases. The analytical method developed was found to be much faster, easier to use, and more accurate than various numerical methods used earlier. Further, the model provides a better physical appreciation of the thermal aspects of the metal cutting process.
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thermal modeling of the metal cutting process part iii temperature rise distribution due to the combined effects of shear plane heat source and the tool Chip Interface frictional heat source
International Journal of Mechanical Sciences, 2001Co-Authors: R Komanduri, Zhen Bing HouAbstract:Abstract This paper is Part III of a 3-part series on the Thermal Modeling of the Metal Cutting Process. In Part I (Komanduri, Hou, International Journal of Mechanical Sciences 2000;42(9):1715–1752), the temperature rise distribution in the workmaterial and the Chip due to shear plane heat source alone was presented using modified Hahn's moving oblique band heat source solution with appropriate image sources for the shear plane (Hahn, Proceedings of the First US National Congress of Applied Mechanics 1951. p. 661–6). In Part II (Komanduri, Hou, International Journal of Mechanical Sciences 2000;43(1):57–88), the temperature rise distribution due to the frictional heat source at the tool–Chip Interface alone is considered using the modified Jaeger's moving-band (in the Chip) and stationary rectangular (in the tool) heat source solutions (Jaeger, Proceedings of the Royal Society of New SouthWales, 1942;76:203–24; Carlsaw, Jaeger. Conduction of heat in solids, Oxford, UK: Oxford University Press, 1959) with appropriate image sources and non-uniform distribution of heat intensity. The matching of the temperature rise distribution at the tool–Chip contact Interface for a moving-band (Chip) and a stationary rectangular heat source (tool) was accomplished using functional analysis technique, originally proposed by Chao and Trigger (Transactions of ASME 1955;75:1107–21). This paper (Part III) deals with the temperature rise distribution in metal cutting due to the combined effect of shear plane heat source in the primary shear zone and frictional heat source at the tool–Chip Interface. The basic approach is similar to that presented in Parts I and II. The model was applied to two cases of metal cutting, namely, conventional machining of steel with a carbide tool at high Peclet numbers (≈5–20) using data from Chao and Trigger (Transactions of ASME 1955;75:1107–21) and ultraprecision machining of aluminum using a single-crystal diamond at low Peclet numbers (≈0.5) using data from Ueda et al. (Annals of CIRP1998;47(1):41–4). The analytical results were found to be in good agreement with the experimental results, thus validating the model. Using relevant computer programs developed for the analytical solutions, the computation of the temperature rise distributions in the workmaterial, the Chip, and the tool were found. The analytical method was found to be much easier, faster, and more accurate to use than the numerical methods used (e.g., Dutt, Brewer, International Journal of Production Research 1964;4:91–114; Tay, Stevenson, de Vahl Davis, Proceedings of the Institution of Mechanical Engineers (London) 1974;188:627). The analytical model also provides a better physical understanding of the thermal process in metal cutting.
Tugrul Ozel - One of the best experts on this subject based on the ideXlab platform.
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predictive analytical and thermal modeling of orthogonal cutting process part i predictions of tool forces stresses and temperature distributions
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2006Co-Authors: Yigit Karpat, Tugrul OzelAbstract:In this paper, a predictive thermal and analytical modeling approach for orthogonal cutting process is introduced to conveniently calculate forces, stress, and temperature distributions. The modeling approach is based on the work material constitutive model, which depends on strain, strain rate, and temperature. In thermal modeling, oblique moving band heat source theory is utilized and analytically combined with modified Oxley's parallel shear zone theory. Normal stress distribution on the tool rake face is modeled as nonuniform with a power-law relationship. Hence, nonuniform heat intensity at the tool-Chip Interface is obtained from the predicted stress distributions utilizing slip line field analysis of the modified secondary shear zone. Heat sources from shearing in the primary zone and friction at the tool-Chip Interface are combined, heat partition ratios are determined for temperature equilibrium to obtain temperature distributions depending on cutting conditions. Model validation is performed by comparing some experimental results with the predictions for machining of AISI 1045 steel, AL 6082-T6, and AL 6061-T6 aluminum. Close agreements with the experiments are observed. A set of detailed, analytically computed stress and temperature distributions is presented.
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the influence of friction models on finite element simulations of machining
International Journal of Machine Tools & Manufacture, 2006Co-Authors: Tugrul OzelAbstract:In the analysis of orthogonal cutting process using finite element (FE) simulations, predictions are greatly influenced by two major factors; a) flow stress characteristics of work material at cutting regimes and b) friction characteristics mainly at the tool-Chip Interface. The uncertainty of work material flow stress upon FE simulations may be low when there is a constitutive model for work material that is obtained empirically from high-strain rate and temperature deformation tests. However, the difficulty arises when one needs to implement accurate friction models for cutting simulations using a particular FE formulation. In this study, an updated Lagrangian finite element formulation is used to simulate continuous Chip formation process in orthogonal cutting of low carbon free-cutting steel. Experimentally measured stress distributions on the tool rake face are utilized in developing several different friction models. The effects of tool-Chip interfacial friction models on the FE simulations are investigated. The comparison results depict that the friction modeling at the tool-Chip Interface has significant influence on the FE simulations of machining. Specifically, variable friction models that are developed from the experimentally measured normal and frictional stresses at the tool rake face resulted in most favorable predictions. Predictions presented in this work also justify that the FE simulation technique used for orthogonal cutting process can be an accurate and viable analysis as long as flow stress behavior of the work material is valid at the machining regimes and the friction characteristics at the tool-Chip Interface is modeled properly.
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a methodology to determine work material flow stress and tool Chip interfacial friction properties by using analysis of machining
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2006Co-Authors: Tugrul Ozel, Erol ZerenAbstract:In this paper, we develop a methodology to determine flow stress at the machining regimes and friction characteristics at the tool-Chip Interface from the results of orthogonal cutting tests. We utilize metal cutting analysis originally developed by late Oxley and present some improvements. We also evaluate several temperature models in calculating the average temperatures at primary and secondary deformation zones and present comparisons with the experimental data obtained for AISI 1045 steel through assessment of machining models (AMM) activity. The proposed methodology utilizes measured forces and Chip thickness obtained through a basic orthogonal cutting test. We conveniently determine work material flow stress at the primary deformation zone and the interfacial friction characteristics along the tool rake face. Calculated friction characteristics include parameters of the normal and frictional stress distributions on the rake face that are maximum normal stress Nmax, power exponent for the normal stress distribution, a, length of the plastic contact, lp, length of the tool-Chip contact, lc, the average shear flow stress at tool-Chip Interface, kChip, and an average coefficient of friction, e, in the sliding region of the tool-Chip Interface. Determined flow stress data from orthogonal cutting tests is combined with the flow stress measured through split-hopkinson pressure bar (SHPB) tests and the Johnson-Cook work material model is obtained. Therefore, with this methodology, we extend the applicability of a Johnson-Cook work material model to machining regimes. DOI: 10.1115/1.2118767
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identification of friction factors for chamfered and honed tools through slip line field analysis
ASME 2006 International Manufacturing Science and Engineering Conference, 2006Co-Authors: Yigit Karpat, Tugrul OzelAbstract:Analysis of tool-Chip friction for tools with edge design in metal cutting helps to understand the complex material behavior around the cutting edge of the tool. The results of this analysis can be used to identify optimum tool edge design to achieve the most desirable machining performance. In this study, slip-line field analysis approach is used to investigate the average friction factor at the tool-Chip Interface and the dead metal zone phenomenon in orthogonal cutting for chamfered and honed tools. In an experimental set-up, an orthogonal cutting test of AISI 4340 steel is performed. Measured forces are utilized in identifying the friction factors at the tool-Interface for both chamfered and honed tools for varying feed rates. Comparison of predicted and measured forces indicates good agreements. The results of this study can be utilized in designing friction at tool-Chip Interface for Finite Element simulations of machining with edge design tools. This study can also be extended to waterfall hone tools to identify the most optimum cutting edge geometry.Copyright © 2006 by ASME
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identification of friction factors for chamfered and honed tools through slip line field analysis
ASME 2006 International Manufacturing Science and Engineering Conference, 2006Co-Authors: Yigit Karpat, Tugrul OzelAbstract:Analysis of tool-Chip friction for tools with edge design in metal cutting helps to understand the complex material behavior around the cutting edge of the tool. The results of this analysis can be used to identify optimum tool edge design to achieve the most desirable machining performance. In this study, slip-line field analysis approach is used to investigate the average friction factor at the tool-Chip Interface and the dead metal zone phenomenon in orthogonal cutting for chamfered and honed tools. In an experimental set-up, an orthogonal cutting test of AISI 4340 steel is performed. Measured forces are utilized in identifying the friction factors at the tool-Interface for both chamfered and honed tools for varying feed rates. Comparison of predicted and measured forces indicates good agreements. The results of this study can be utilized in designing friction at tool-Chip Interface for Finite Element simulations of machining with edge design tools. This study can also be extended to waterfall hone tools to identify the most optimum cutting edge geometry.Copyright © 2006 by ASME
Loncar Marko - One of the best experts on this subject based on the ideXlab platform.
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low loss fiber to Chip Interface for lithium niobate photonic integrated circuits
Optics Letters, 2019Co-Authors: Mian Zhang, Amirhassan Shamsansari, Rongrong Zhu, Cheng Wang, Loncar MarkoAbstract:Integrated lithium niobate (LN) photonic circuits have recently emerged as a promising candidate for advanced photonic functions such as high-speed modulation, nonlinear frequency conversion, and frequency comb generation. For practical applications, optical Interfaces that feature low fiber-to-Chip coupling losses are essential. So far, the fiber-to-Chip loss (commonly >10 dB/facet) has dominated the total insertion losses of typical LN photonic integrated circuits, where on-Chip losses can be as low as 0.03–0.1 dB/cm. Here we experimentally demonstrate a low-loss mode size converter for coupling between a standard lensed fiber and sub-micrometer LN rib waveguides. The coupler consists of two inverse tapers that convert the small optical mode of a rib waveguide into a symmetrically guided mode of a LN nanowire, featuring a larger mode area matched to that of a tapered optical fiber. The measured fiber-to-Chip coupling loss is lower than 1.7 dB/facet with high fabrication tolerance and repeatability. Our results open the door for practical integrated LN photonic circuits efficiently Interfaced with optical fibers.