The Experts below are selected from a list of 3390 Experts worldwide ranked by ideXlab platform
Paulo J Davim - One of the best experts on this subject based on the ideXlab platform.
-
machinability analysis in turning tungsten copper composite for application in edm electrodes
International Journal of Refractory Metals & Hard Materials, 2010Co-Authors: V N Gaitonde, S. R. Karnik, M Faustino, Paulo J DavimAbstract:Abstract Electro-discharge machining (EDM) is widely used in tooling industry, where it is applied on materials, which are too hard to be machined with conventional techniques. The tungsten–copper is broadly used as an EDM electrode for machining of die steel and tungsten carbide workpieces. As, tungsten–copper electrode is more costly than conventional electrodes, there is a need to understand the machinability aspects in turning of this material. Hence, an attempt has been made in this paper to study the effects of Cutting conditions on machinability characteristics such as Cutting Force, feed Force, depth Force, machining Force, power, Specific Cutting Force, arithmetic average surface roughness and maximum peak to valley height during tungsten–copper turning with K10 carbide Cutting tool. The response surface methodology (RSM) based second order mathematical models of machinability aspects are developed using the data obtained through full factorial design (FFD). The adequacy of the machinability models is tested through the analysis of variance (ANOVA). The response surface analysis reveals that a combination of higher Cutting speed with low-to-medium feed rate is advantageous in reducing the Forces, power and surface roughness, which in turn increases the Specific Cutting Force.
-
analysis of machinability during hard turning of cold work tool steel type aisi d2
Materials and Manufacturing Processes, 2009Co-Authors: V N Gaitonde, Luis Figueira, S. R. Karnik, Paulo J DavimAbstract:Hard turning is an attractive replacement for grinding operations due to numerous advantages such as low capital investment, shorter setup time, higher material removal rate, better surface integrity, and elimination of Cutting fluids. As a potential alternative process, there is a need to assess the machinability in high-precision and high-hardened components. The current study establishes the relationships between the Cutting conditions (Cutting speed, feed rate, and machining time) on machinability aspects (machining Force, power, Specific Cutting Force, surface roughness, and tool wear). The response surface methodology-based mathematical models are proposed for modeling and analyzing the effects of process parameters on machinability during turning of high chromium AISI D2 cold work tool steel using CC650WG wiper ceramic inserts. The experiments have been planned as per full factorial design. From the parametric analysis, it is revealed that the power increases with increase in feed rate, while the s...
-
some studies in metal matrix composites machining using response surface methodology
Journal of Reinforced Plastics and Composites, 2009Co-Authors: V N Gaitonde, S. R. Karnik, Paulo J DavimAbstract:The present study establishes the relationship between Cutting conditions and machinability characteristics during the turning of metal matrix composites (MMC). The investigation aims at determining the effects of Cutting speed and feed rate on machining Force, Cutting power, and Specific Cutting Force by developing second-order mathematical models using response surface methodology (RSM). Aluminum alloy reinForced with 20% of SiC particulates (A 356/20/SiCp-T6) were machined using a polycrystalline diamond (PCD) tool. The experiments have been planned as a full factorial design of experiments (FFD). The analysis of variance (ANOVA) was performed to check the adequacy of the mathematical models. The parametric analysis reveals that the machining Force and Cutting power increase with increase in feed rate while the Specific Cutting Force decreases.
-
machinability investigations in hard turning of aisi d2 cold work tool steel with conventional and wiper ceramic inserts
International Journal of Refractory Metals & Hard Materials, 2009Co-Authors: V N Gaitonde, Luis Figueira, S. R. Karnik, Paulo J DavimAbstract:Hard turning with ceramic Cutting tool has several benefits over grinding process such as elimination of coolant, reduced processing costs, improved material properties, reduced power consumption and increased productivity. Despite its significant advantages, hard turning can not replace all grinding due to lack of data concerning surface quality and tool wear and hence there is a need to study the machinability characteristics in high precision and high-hardened components. An attempt has been made in this paper to analyze the effects of depth of cut and machining time on machinability aspects such as machining Force, power, Specific Cutting Force, surface roughness and tool wear using second order mathematical models during turning of high chromium AISI D2 cold work tool steel with CC650, CC650WG and GC6050WH ceramic inserts. The experiments were planned as per full factorial design (FFD). From the parametric analysis, it is revealed that, the CC650WG wiper insert performs better with reference to surface roughness and tool wear, while the CC650 conventional insert is useful in reducing the machining Force, power and Specific Cutting Force.
-
selection of optimal mql and Cutting conditions for enhancing machinability in turning of brass
Journal of Materials Processing Technology, 2008Co-Authors: V N Gaitonde, S. R. Karnik, Paulo J DavimAbstract:Abstract Minimum quantity of lubrication (MQL) in machining is an established alternative to completely dry or flood lubricating system from the viewpoint of cost, ecology and human health issues. Hence, it is necessary to select proper MQL and Cutting conditions in order to enhance machinability for a given work material. The present work aims at determining the optimum amount of MQL and the most appropriate Cutting speed and feed rate during turning of brass using K10 carbide tool. Taguchi technique with the utility concept, a multi-response optimization method, has been proposed for simultaneous minimization of surface roughness and Specific Cutting Force. The experiments were planned as per Taguchi's L9 orthogonal array with each experiment performed under different conditions of MQL, Cutting speed and feed rate. The analysis of means (ANOM) and analysis of variance (ANOVA) on multi-response signal-to-noise (S/N) ratio were employed for determining the optimal parameter levels and identifying the level of importance of the process parameters. The optimization results indicated that MQL of 200 ml/h, Cutting speed of 200 m/min and a feed rate of 0.05 mm/rev is essential to simultaneously minimize surface roughness and Specific Cutting Force.
Ni Chen - One of the best experts on this subject based on the ideXlab platform.
-
Research on the ploughing Force in micro milling of soft-brittle crystals
'Elsevier BV', 2019Co-Authors: Ni Chen, Qian Jun, Li Liang, Wu Jinming, He Ning, Reynaerts DominiekAbstract:© 2019 Elsevier Ltd The ploughing Force can be assigned to supervisory control of the tool wearing and machining process on-line in micro milling, for the reason that the ploughing Force is closely related with the processed surface quality and radius of Cutting edge. A new theoretical model is established to determine the ploughing Force in micro milling of crystals with soft-brittle characters in consideration of the Cutting edge roundness, and it is verified by Finite Element Method. The ploughing Force decreases quickly with an decrease of the Cutting edge roundness, and it can be controlled to be less than the shearing Force, which helps for obtaining a good machined surface quality, under the condition that the radius of Cutting edge is less than 2.8 μm or the feed speed is larger than 5 μm/z when the radius of Cutting edge is larger than 4.2 μm. Meanwhile, a large feed speed would bring heavy tool traces on the processed surface of soft-brittle crystals, destroying the processed quality. The energy consumption is researched by investigating the Specific Cutting Force, showing that the energy consumption has a sharp increase with a small feed speed. The energy consumption is mainly caused by the ploughing effect, especially for tools with blunt Cutting edge. Therefore, both the micro mill with sharp tool edge or blunt tool edge (under the Cutting condition that the feed speed almost have equal value to the radius of Cutting edge) are highly recommended for micro end milling of soft-brittle crystals.status: publishe
-
Research in minimum undeformed chip thickness and size effect in micro end-milling of potassium dihydrogen phosphate crystal
International Journal of Mechanical Sciences, 2017Co-Authors: Ni Chen, Mingjun Chen, Xudong Pei, Jun Qian, Dominiek ReynaertsAbstract:Abstract Micro-milling is a promising approach to repair the micro-defects on the surface of potassium dihydrogen phosphate (KDP) crystal. However, KDP crystal is difficult to machine due to its properties of soft-brittle and easy deliquescence. This study investigates the minimum undeformed chip thickness hm and the size effect in micro end-milling of KDP crystal by comprehensively analyzing Cutting Force, Specific Cutting Force and machined surface quality. A model of the chip formation, which is capable of connecting the minimum undeformed chip thickness, the undeformed chip thickness and the periodicity of Cutting Force together, is developed to predict the value of minimum undeformed chip thickness. The normalized minimum undeformed chip thickness λe in terms of the ratio of the minimum undeformed chip thickness to the Cutting edge radius re, is estimated to be 0.43 ≤ λe ≤ 0.48. The significantly non-proportional increase of Specific Cutting Force indicates the existence of size effects when the ratio of feed per tooth to Cutting edge radius ft/re is less than 0.7. The machined surface quality also reflects severe size effect by the phenomenon that the micro cracks and brittle pits appear on the groove base, and the value of surface roughness Ra is large when the ratio ft/re is less than 0.5. Furthermore, the surface quality deteriorates and the brittle Cutting appears when the ratio ft/re is much larger than 1 which seems similar to macro-milling. The perfect machined surface with almost no ploughing effect and brittle Cutting is achieved at a ratio ft/re of 0.7. Therefore, a feed per tooth, slightly larger than the minimum undeformed chip thickness but smaller than Cutting edge radius, is recommended for micro-milling of KDP crystal or soft-brittle crystal.
-
Cutting surface quality analysis in micro ball end milling of kdp crystal considering size effect and minimum undeformed chip thickness
Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, 2017Co-Authors: Ni Chen, Mingjun Chen, Xudong PeiAbstract:Abstract Potassium dihydrogen phosphate (KH2PO4 or KDP) crystal is a typical soft-brittle optical crystal, and the size effect and brittle Cutting mode are easy to appear in micro ball end-milling of KDP crystal. In this paper, micro-grooving experiments are conducted to study the size effect and brittle Cutting in micro ball end-milling of KDP crystal with different feed rate and depth of cut. The Cutting Force, machined groove base quality and chip morphology are collected and analyzed carefully. The size effect is discovered by the phenomena of the existence of oscillations and relaxations in Cutting Force and hyper-proportional increase of Specific Cutting Force, when the ratio of feed per tooth to Cutting edge radius ft/re is less than 1. While the brittle Cutting mode is detected through the existence of sharp fluctuations in Cutting Force and cracks on the groove base when the ratio ft/re is larger than 2. From the further comprehensive analysis of Cutting Force, Specific Cutting Force, machined groove base quality and chip morphology, the Cutting parameters with ratios of the maximum undeformed chip thickness in one Cutting circle to Cutting edge radius hmax/re around 0.14, 0.2 and 0.4 are regarded as size effect, optimal and brittle Cutting points, respectively. The size effect, ductile Cutting and brittle Cutting zones are divided by the size effect and brittle Cutting boundaries (points). Among the optimal points, the depth of cut of 2 μm with the ratio ft/re of 1 is the optimal Cutting parameter for micro ball end-milling of KDP crystal.
-
Research in minimum undeformed chip thickness and size effect in micro end-milling of potassium dihydrogen phosphate crystal
'Elsevier BV', 2017Co-Authors: Ni Chen, Chen Mingjun, Wu Chunya, Pei Xudong, Qian Jun, Reynaerts DominiekAbstract:© 2017 Elsevier Ltd Micro-milling is a promising approach to repair the micro-defects on the surface of potassium dihydrogen phosphate (KDP) crystal. However, KDP crystal is difficult to machine due to its properties of soft-brittle and easy deliquescence. This study investigates the minimum undeformed chip thickness hm and the size effect in micro end-milling of KDP crystal by comprehensively analyzing Cutting Force, Specific Cutting Force and machined surface quality. A model of the chip formation, which is capable of connecting the minimum undeformed chip thickness, the undeformed chip thickness and the periodicity of Cutting Force together, is developed to predict the value of minimum undeformed chip thickness. The normalized minimum undeformed chip thickness λe in terms of the ratio of the minimum undeformed chip thickness to the Cutting edge radius re, is estimated to be 0.43 ≤ λe ≤ 0.48. The significantly non-proportional increase of Specific Cutting Force indicates the existence of size effects when the ratio of feed per tooth to Cutting edge radius ft/re is less than 0.7. The machined surface quality also reflects severe size effect by the phenomenon that the micro cracks and brittle pits appear on the groove base, and the value of surface roughness Ra is large when the ratio ft/re is less than 0.5. Furthermore, the surface quality deteriorates and the brittle Cutting appears when the ratio ft/re is much larger than 1 which seems similar to macro-milling. The perfect machined surface with almost no ploughing effect and brittle Cutting is achieved at a ratio ft/re of 0.7. Therefore, a feed per tooth, slightly larger than the minimum undeformed chip thickness but smaller than Cutting edge radius, is recommended for micro-milling of KDP crystal or soft-brittle crystal.status: publishe
V N Gaitonde - One of the best experts on this subject based on the ideXlab platform.
-
machinability analysis in turning tungsten copper composite for application in edm electrodes
International Journal of Refractory Metals & Hard Materials, 2010Co-Authors: V N Gaitonde, S. R. Karnik, M Faustino, Paulo J DavimAbstract:Abstract Electro-discharge machining (EDM) is widely used in tooling industry, where it is applied on materials, which are too hard to be machined with conventional techniques. The tungsten–copper is broadly used as an EDM electrode for machining of die steel and tungsten carbide workpieces. As, tungsten–copper electrode is more costly than conventional electrodes, there is a need to understand the machinability aspects in turning of this material. Hence, an attempt has been made in this paper to study the effects of Cutting conditions on machinability characteristics such as Cutting Force, feed Force, depth Force, machining Force, power, Specific Cutting Force, arithmetic average surface roughness and maximum peak to valley height during tungsten–copper turning with K10 carbide Cutting tool. The response surface methodology (RSM) based second order mathematical models of machinability aspects are developed using the data obtained through full factorial design (FFD). The adequacy of the machinability models is tested through the analysis of variance (ANOVA). The response surface analysis reveals that a combination of higher Cutting speed with low-to-medium feed rate is advantageous in reducing the Forces, power and surface roughness, which in turn increases the Specific Cutting Force.
-
analysis of machinability during hard turning of cold work tool steel type aisi d2
Materials and Manufacturing Processes, 2009Co-Authors: V N Gaitonde, Luis Figueira, S. R. Karnik, Paulo J DavimAbstract:Hard turning is an attractive replacement for grinding operations due to numerous advantages such as low capital investment, shorter setup time, higher material removal rate, better surface integrity, and elimination of Cutting fluids. As a potential alternative process, there is a need to assess the machinability in high-precision and high-hardened components. The current study establishes the relationships between the Cutting conditions (Cutting speed, feed rate, and machining time) on machinability aspects (machining Force, power, Specific Cutting Force, surface roughness, and tool wear). The response surface methodology-based mathematical models are proposed for modeling and analyzing the effects of process parameters on machinability during turning of high chromium AISI D2 cold work tool steel using CC650WG wiper ceramic inserts. The experiments have been planned as per full factorial design. From the parametric analysis, it is revealed that the power increases with increase in feed rate, while the s...
-
some studies in metal matrix composites machining using response surface methodology
Journal of Reinforced Plastics and Composites, 2009Co-Authors: V N Gaitonde, S. R. Karnik, Paulo J DavimAbstract:The present study establishes the relationship between Cutting conditions and machinability characteristics during the turning of metal matrix composites (MMC). The investigation aims at determining the effects of Cutting speed and feed rate on machining Force, Cutting power, and Specific Cutting Force by developing second-order mathematical models using response surface methodology (RSM). Aluminum alloy reinForced with 20% of SiC particulates (A 356/20/SiCp-T6) were machined using a polycrystalline diamond (PCD) tool. The experiments have been planned as a full factorial design of experiments (FFD). The analysis of variance (ANOVA) was performed to check the adequacy of the mathematical models. The parametric analysis reveals that the machining Force and Cutting power increase with increase in feed rate while the Specific Cutting Force decreases.
-
machinability investigations in hard turning of aisi d2 cold work tool steel with conventional and wiper ceramic inserts
International Journal of Refractory Metals & Hard Materials, 2009Co-Authors: V N Gaitonde, Luis Figueira, S. R. Karnik, Paulo J DavimAbstract:Hard turning with ceramic Cutting tool has several benefits over grinding process such as elimination of coolant, reduced processing costs, improved material properties, reduced power consumption and increased productivity. Despite its significant advantages, hard turning can not replace all grinding due to lack of data concerning surface quality and tool wear and hence there is a need to study the machinability characteristics in high precision and high-hardened components. An attempt has been made in this paper to analyze the effects of depth of cut and machining time on machinability aspects such as machining Force, power, Specific Cutting Force, surface roughness and tool wear using second order mathematical models during turning of high chromium AISI D2 cold work tool steel with CC650, CC650WG and GC6050WH ceramic inserts. The experiments were planned as per full factorial design (FFD). From the parametric analysis, it is revealed that, the CC650WG wiper insert performs better with reference to surface roughness and tool wear, while the CC650 conventional insert is useful in reducing the machining Force, power and Specific Cutting Force.
-
selection of optimal mql and Cutting conditions for enhancing machinability in turning of brass
Journal of Materials Processing Technology, 2008Co-Authors: V N Gaitonde, S. R. Karnik, Paulo J DavimAbstract:Abstract Minimum quantity of lubrication (MQL) in machining is an established alternative to completely dry or flood lubricating system from the viewpoint of cost, ecology and human health issues. Hence, it is necessary to select proper MQL and Cutting conditions in order to enhance machinability for a given work material. The present work aims at determining the optimum amount of MQL and the most appropriate Cutting speed and feed rate during turning of brass using K10 carbide tool. Taguchi technique with the utility concept, a multi-response optimization method, has been proposed for simultaneous minimization of surface roughness and Specific Cutting Force. The experiments were planned as per Taguchi's L9 orthogonal array with each experiment performed under different conditions of MQL, Cutting speed and feed rate. The analysis of means (ANOM) and analysis of variance (ANOVA) on multi-response signal-to-noise (S/N) ratio were employed for determining the optimal parameter levels and identifying the level of importance of the process parameters. The optimization results indicated that MQL of 200 ml/h, Cutting speed of 200 m/min and a feed rate of 0.05 mm/rev is essential to simultaneously minimize surface roughness and Specific Cutting Force.
Dominiek Reynaerts - One of the best experts on this subject based on the ideXlab platform.
-
Research in minimum undeformed chip thickness and size effect in micro end-milling of potassium dihydrogen phosphate crystal
International Journal of Mechanical Sciences, 2017Co-Authors: Ni Chen, Mingjun Chen, Xudong Pei, Jun Qian, Dominiek ReynaertsAbstract:Abstract Micro-milling is a promising approach to repair the micro-defects on the surface of potassium dihydrogen phosphate (KDP) crystal. However, KDP crystal is difficult to machine due to its properties of soft-brittle and easy deliquescence. This study investigates the minimum undeformed chip thickness hm and the size effect in micro end-milling of KDP crystal by comprehensively analyzing Cutting Force, Specific Cutting Force and machined surface quality. A model of the chip formation, which is capable of connecting the minimum undeformed chip thickness, the undeformed chip thickness and the periodicity of Cutting Force together, is developed to predict the value of minimum undeformed chip thickness. The normalized minimum undeformed chip thickness λe in terms of the ratio of the minimum undeformed chip thickness to the Cutting edge radius re, is estimated to be 0.43 ≤ λe ≤ 0.48. The significantly non-proportional increase of Specific Cutting Force indicates the existence of size effects when the ratio of feed per tooth to Cutting edge radius ft/re is less than 0.7. The machined surface quality also reflects severe size effect by the phenomenon that the micro cracks and brittle pits appear on the groove base, and the value of surface roughness Ra is large when the ratio ft/re is less than 0.5. Furthermore, the surface quality deteriorates and the brittle Cutting appears when the ratio ft/re is much larger than 1 which seems similar to macro-milling. The perfect machined surface with almost no ploughing effect and brittle Cutting is achieved at a ratio ft/re of 0.7. Therefore, a feed per tooth, slightly larger than the minimum undeformed chip thickness but smaller than Cutting edge radius, is recommended for micro-milling of KDP crystal or soft-brittle crystal.
C Lu - One of the best experts on this subject based on the ideXlab platform.
-
study of materials deformation in nanometric Cutting by large scale molecular dynamics simulations
Nanoscale Research Letters, 2009Co-Authors: C Lu, Yongwei ZhangAbstract:Nanometric Cutting involves materials removal and deformation evolution in the surface at nanometer scale. At this length scale, atomistic simulation is a very useful tool to study the Cutting process. In this study, large-scale molecular dynamics (MD) simulations with the model size up to 10 millions atoms have been performed to study three-dimensional nanometric Cutting of copper. The EAM potential and Morse potential are used, respectively, to compute the interaction between workpiece atoms and the interactions between workpiece atoms and tool atoms. The material behavior, surface and subsurface deformation, dislocation movement, and Cutting Forces during the Cutting processes are studied. We show that the MD simulation model of nanometric Cutting has to be large enough to eliminate the boundary effect. Moreover, the Cutting speed and the Cutting depth have to be considered in determining a suitable model size for the MD simulations. We have observed that the nanometric Cutting process is accompanied with complex material deformation, dislocation formation, and movement. We find that as the Cutting depth decreases, the tangential Cutting Force decreases faster than the normal Cutting Force. The simulation results reveal that as the Cutting depth decreases, the Specific Cutting Force increases, i.e., “size effect” exists in nanometric Cutting.
-
large scale molecular dynamics study of nanometric machining of copper
Computational Materials Science, 2007Co-Authors: C LuAbstract:Abstract Nanometric machining involves removal of materials at the order of a few nanometers or less. At such a small length scale, molecular dynamics (MD) simulation is an important tool in studying the nanometric machining mechanism and process. In this study, a series of large scale MD simulations with the model size of more than four-million atoms have been performed to study the nanometric machining of copper. The dislocations at finite temperature during the Cutting processes are identified and their nucleation and movement are studied. The effects of Cutting depth, Cutting speed, crystal orientation and Cutting direction on the material deformation, lattice defects and Cutting Forces are investigated. The simulation results show that a smaller Cutting depth results in less plastic deformation and fewer dislocations in the workpiece and thus result in a smoother machined surface. It is found that as the Cutting depth decreases, the Specific Cutting Force increases rapidly, which shows that the “size effect” exists in nanometric machining. It is observed that a higher Cutting speed results in more lattice defects at the Cutting region and higher Cutting Forces. It is revealed that the crystal orientation and Cutting direction have a strong effect on material deformation, dislocation movement and Cutting Forces.
