J. Paulo Davim | University of Aveiro (original) (raw)

Papers by J. Paulo Davim

Research paper thumbnail of A surface roughness analysis in turning of polyamide PA-6 using statistical techniques

International Journal of Materials and Product Technology, 2010

This work is aimed at studying the impact of cutting conditions (cutting speed and feed) on surfa... more This work is aimed at studying the impact of cutting conditions (cutting speed and feed) on surface roughness in turning of Polyamide PA-6, using two different cutting tool materials namely, Polycrystalline Diamond (PCD) and K15 cemented carbide. By applying Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) to the experimental data, predictive models are developed exhibiting excellent correlation and revealing that feed exerts the strongest influence on roughness, whilst cutting speed has a secondary effect. On the other hand the PCD tool tends to provide better finish. These findings permit optimised selection of cutting conditions and tool materials.

Research paper thumbnail of Influence of the chemical composition on the machinability of brasses

Journal of Materials Processing Technology, 2005

Although brasses are essentially copper and zinc alloys, they also contain other alloying element... more Although brasses are essentially copper and zinc alloys, they also contain other alloying elements such as lead, silicon, aluminium, iron, tin, manganese, nickel or arsenic whose presence and content are responsible for the wide variety of properties inherent to these materials. In this article, the effect of the chemical composition of brasses, considering each alloying element and the effective copper content, upon the machinability has been investigated. For that purpose, machinability tests have been carried out on a CNC lathe under lubricated conditions. The study includes both commercial alloys and samples prepared in laboratory. The experimental procedure consists on turning operations, during which cutting forces and surface roughness obtained in brass workpieces are measured. The chip class is accordingly evaluated. The statistic treatment of the results enables the establishment of correlations between the studied machinability parameters and the chemical composition of different kinds of brasses.

Research paper thumbnail of Impact of surface roughness of diamond coatings on the cutting performance when dry machining of graphite

International Journal of Manufacturing Technology and Management, 2008

... The cutting forces were measured by the DynoWareTM data acquisition system. ... at the Centre... more ... The cutting forces were measured by the DynoWareTM data acquisition system. ... at the Centre for Mechanical Technology and Automation in the Department of Mechanical Engineering at ... films and he is on the Editorial Board of the International Journal of Nanomanufacturing. ...

Research paper thumbnail of Interdisciplinary Mechatronics engineering and science: problem-solving, creative-thinking and concurrent design synergy

International Journal of Mechatronics and Manufacturing Systems, 2008

Page 1. 4 Int. J. Mechatronics and Manufacturing Systems, Vol. 1, No. 1, 2008 Copyright © 2008 In... more Page 1. 4 Int. J. Mechatronics and Manufacturing Systems, Vol. 1, No. 1, 2008 Copyright © 2008 Inderscience Enterprises Ltd. Interdisciplinary Mechatronics engineering and science: problem-solving, creative-thinking and concurrent design synergy Maki K. Habib ...

Research paper thumbnail of Modeling and optimization in tribological parameters of polyether ether ketone matrix composites using D-optimal design

Research paper thumbnail of Application of artificial neural network for the prediction of surface roughness in drilling GFRP composites

Materials Science Forum, 2013

In the present study, artificial neural network (ANN) model has been developed to predict materia... more In the present study, artificial neural network (ANN) model has been developed to predict material removal rate (MRR), tool wear rate (TWR) and surface roughness (R a ) in Electro-discharge machining (EDM). A feed-forward neural network based on Levenberg-Marquardt back propagation technique of sigmoid activation function has been used. For this purpose, several neural network models with varying number of neurons at hidden layer have been tried. Finally, it has been found that at 10 neurons, model gives best prediction result. The validity of the neural network model has been checked with experimental data, and it has been concluded that the artificial neural network can predict the process performance with reasonable accuracy.

Research paper thumbnail of Turning of Brasses Using Minimum Quantity of Lubricant (MQL) and Flooded Lubricant Conditions

Materials and Manufacturing Processes, 2007

A lot of effort is being carried out to reduce the use of lubricants in metal machining operation... more A lot of effort is being carried out to reduce the use of lubricants in metal machining operations from the viewpoint of cost, ecology and human health issues. Minimal quantity lubrication (MQL) is now an established alternative to conventional flood lubricant system. ...

Research paper thumbnail of Analysis of Surface Integrity in Drilling Metal Matrix and Hybrid Metal Matrix Composites

Journal of Materials Science & Technology, 2012

Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix ... more Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix and two reinforcements in various forms, bonded together at the atomic level in the composite. Despite their higher specific properties of strength and stiffness, the non homogeneous and anisotropic nature combined with the abrasive reinforcements render their machining difficult. In this paper, the surface integrity of machining in drilling hybrid composites has been discussed. Drilling tests are carried out at different spindle speed, feed rates, and different drill tool materials to investigate the effect of the various cutting parameters on the surface quality and the extent of the deformation of drilled surface due to drilling. Materials used for the present investigation are Al356/10SiC (wt%) metal matrix and Al356/10SiC-3mica (wt%) hybrid composites. The composites are fabricated using stir casting route. The drilling tests are conducted on vertical computer numeric control (CNC) machining center using carbide, coated carbide and polycrystalline diamond (PCD) drills. The surface roughness decreases with increasing spindle speed and increases with increasing feed rate. The machined surface is analyzed by scanning electron microscopy (SEM). SEM images of the machined surfaces indicate the presence of grooves and pits. Microhardness depth profiles indicate that the subsurface damage is limited to the top of 100-250 µm.

Research paper thumbnail of Influence of Drill Point Angle in High Speed Drilling of Glass Fiber Reinforced Plastics

Journal of Composite Materials, 2008

... Fiber Reinforced Plastics K. PALANIKUMAR* Department of Mechanical and Production Engineering... more ... Fiber Reinforced Plastics K. PALANIKUMAR* Department of Mechanical and Production Engineering Sathyabama University, Chennai – 600 119, India J. CAMPOS RUBIO AND AM ABRAO Department of Mechanical Engineering, University of Minas Gerais Av. ...

Research paper thumbnail of Experimental studies on hole quality and machinability characteristics in drilling of unreinforced and reinforced polyamides

Journal of Composite Materials, 2014

In this study, experimental studies on hole quality and machinability in drilling of unreinforced... more In this study, experimental studies on hole quality and machinability in drilling of unreinforced polyamide (PA6) and reinforced polyamide with 30% of glass fibers (PA66-GF30) using cemented carbide (K20) tool have been carried out. The experiments have been planned as per full factorial design of experiments. The effects of spindle speed, feed rate, and point angle on hole quality such as hole diameter and circularity error; the machinability characteristics such as thrust force and specific cutting coefficient have been analyzed by developing response surface methodology based second-order mathematical models. The parametric analysis shows that the quality of holes can be improved by proper selection of cutting parameters. The analysis also indicates the influence of reinforced fiber on proposed machinability characteristics during drilling of polyamides.

Research paper thumbnail of Optimization of Electrical Discharge Machining Process Parameters Using Desirability Approach

Applied Mechanics and Materials, 2012

In this paper, the application of the Taguchi method with fuzzy logic for optimizing the electric... more In this paper, the application of the Taguchi method with fuzzy logic for optimizing the electrical discharge machining process with multiple performance characteristics has been reported. A multi-response performance index is used to solve the electrical discharge machining process with multiple performance characteristics. The machining parameters (the workpiece polarity, pulse-on time, duty factor, open discharge voltage, discharge current and dielectric¯uid) are optimized with considerations of the multiple performance characteristics (electrode wear ratio and material removal rate). Experimental results are presented to demonstrate the effectiveness of this approach. #

Research paper thumbnail of Prediction of cutting forces during turning PA66 GF-30 glass fiber reinforced polyamide by soft computing techniques

Materials Science Forum, 2013

In the present paper the influence of the main cutting parameters on process performance during l... more In the present paper the influence of the main cutting parameters on process performance during longitudinal turning of PA66 GF-30 Glass Fiber Reinforced Polyamide is investigated. The selected cutting parameters are cutting speed and feed-rate whilst depth of cut is kept constant. As outputs (responses), cutting force components F t , F V and F r were selected. Test specimens in the form of round bars and cemented carbide cutting tool were used during the experimental process. Fifteen experiments were conducted having all different combinations of cutting parameter values. Analysis of Variance (ANOVA), statistical approaches and soft computing techniques (artificial neural network) were applied in order to formulate stochastic models for relating the responses with main cutting parameters. The results obtained, indicate that the proposed soft computing techniques can be effectively used to predict the cutting force components (F t , F V and F r ) thus; facilitating decision making during process planning since costly and time-consuming experimentation can be avoided.

Research paper thumbnail of A surface roughness analysis in turning of polyamide PA-6 using statistical techniques

International Journal of Materials and Product Technology, 2010

This work is aimed at studying the impact of cutting conditions (cutting speed and feed) on surfa... more This work is aimed at studying the impact of cutting conditions (cutting speed and feed) on surface roughness in turning of Polyamide PA-6, using two different cutting tool materials namely, Polycrystalline Diamond (PCD) and K15 cemented carbide. By applying Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) to the experimental data, predictive models are developed exhibiting excellent correlation and revealing that feed exerts the strongest influence on roughness, whilst cutting speed has a secondary effect. On the other hand the PCD tool tends to provide better finish. These findings permit optimised selection of cutting conditions and tool materials.

Research paper thumbnail of Influence of the chemical composition on the machinability of brasses

Journal of Materials Processing Technology, 2005

Although brasses are essentially copper and zinc alloys, they also contain other alloying element... more Although brasses are essentially copper and zinc alloys, they also contain other alloying elements such as lead, silicon, aluminium, iron, tin, manganese, nickel or arsenic whose presence and content are responsible for the wide variety of properties inherent to these materials. In this article, the effect of the chemical composition of brasses, considering each alloying element and the effective copper content, upon the machinability has been investigated. For that purpose, machinability tests have been carried out on a CNC lathe under lubricated conditions. The study includes both commercial alloys and samples prepared in laboratory. The experimental procedure consists on turning operations, during which cutting forces and surface roughness obtained in brass workpieces are measured. The chip class is accordingly evaluated. The statistic treatment of the results enables the establishment of correlations between the studied machinability parameters and the chemical composition of different kinds of brasses.

Research paper thumbnail of Impact of surface roughness of diamond coatings on the cutting performance when dry machining of graphite

International Journal of Manufacturing Technology and Management, 2008

... The cutting forces were measured by the DynoWareTM data acquisition system. ... at the Centre... more ... The cutting forces were measured by the DynoWareTM data acquisition system. ... at the Centre for Mechanical Technology and Automation in the Department of Mechanical Engineering at ... films and he is on the Editorial Board of the International Journal of Nanomanufacturing. ...

Research paper thumbnail of Interdisciplinary Mechatronics engineering and science: problem-solving, creative-thinking and concurrent design synergy

International Journal of Mechatronics and Manufacturing Systems, 2008

Page 1. 4 Int. J. Mechatronics and Manufacturing Systems, Vol. 1, No. 1, 2008 Copyright © 2008 In... more Page 1. 4 Int. J. Mechatronics and Manufacturing Systems, Vol. 1, No. 1, 2008 Copyright © 2008 Inderscience Enterprises Ltd. Interdisciplinary Mechatronics engineering and science: problem-solving, creative-thinking and concurrent design synergy Maki K. Habib ...

Research paper thumbnail of Modeling and optimization in tribological parameters of polyether ether ketone matrix composites using D-optimal design

Research paper thumbnail of Application of artificial neural network for the prediction of surface roughness in drilling GFRP composites

Materials Science Forum, 2013

In the present study, artificial neural network (ANN) model has been developed to predict materia... more In the present study, artificial neural network (ANN) model has been developed to predict material removal rate (MRR), tool wear rate (TWR) and surface roughness (R a ) in Electro-discharge machining (EDM). A feed-forward neural network based on Levenberg-Marquardt back propagation technique of sigmoid activation function has been used. For this purpose, several neural network models with varying number of neurons at hidden layer have been tried. Finally, it has been found that at 10 neurons, model gives best prediction result. The validity of the neural network model has been checked with experimental data, and it has been concluded that the artificial neural network can predict the process performance with reasonable accuracy.

Research paper thumbnail of Turning of Brasses Using Minimum Quantity of Lubricant (MQL) and Flooded Lubricant Conditions

Materials and Manufacturing Processes, 2007

A lot of effort is being carried out to reduce the use of lubricants in metal machining operation... more A lot of effort is being carried out to reduce the use of lubricants in metal machining operations from the viewpoint of cost, ecology and human health issues. Minimal quantity lubrication (MQL) is now an established alternative to conventional flood lubricant system. ...

Research paper thumbnail of Analysis of Surface Integrity in Drilling Metal Matrix and Hybrid Metal Matrix Composites

Journal of Materials Science & Technology, 2012

Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix ... more Hybrid metal matrix composites consist of at least three constituents-a metal or an alloy matrix and two reinforcements in various forms, bonded together at the atomic level in the composite. Despite their higher specific properties of strength and stiffness, the non homogeneous and anisotropic nature combined with the abrasive reinforcements render their machining difficult. In this paper, the surface integrity of machining in drilling hybrid composites has been discussed. Drilling tests are carried out at different spindle speed, feed rates, and different drill tool materials to investigate the effect of the various cutting parameters on the surface quality and the extent of the deformation of drilled surface due to drilling. Materials used for the present investigation are Al356/10SiC (wt%) metal matrix and Al356/10SiC-3mica (wt%) hybrid composites. The composites are fabricated using stir casting route. The drilling tests are conducted on vertical computer numeric control (CNC) machining center using carbide, coated carbide and polycrystalline diamond (PCD) drills. The surface roughness decreases with increasing spindle speed and increases with increasing feed rate. The machined surface is analyzed by scanning electron microscopy (SEM). SEM images of the machined surfaces indicate the presence of grooves and pits. Microhardness depth profiles indicate that the subsurface damage is limited to the top of 100-250 µm.

Research paper thumbnail of Influence of Drill Point Angle in High Speed Drilling of Glass Fiber Reinforced Plastics

Journal of Composite Materials, 2008

... Fiber Reinforced Plastics K. PALANIKUMAR* Department of Mechanical and Production Engineering... more ... Fiber Reinforced Plastics K. PALANIKUMAR* Department of Mechanical and Production Engineering Sathyabama University, Chennai – 600 119, India J. CAMPOS RUBIO AND AM ABRAO Department of Mechanical Engineering, University of Minas Gerais Av. ...

Research paper thumbnail of Experimental studies on hole quality and machinability characteristics in drilling of unreinforced and reinforced polyamides

Journal of Composite Materials, 2014

In this study, experimental studies on hole quality and machinability in drilling of unreinforced... more In this study, experimental studies on hole quality and machinability in drilling of unreinforced polyamide (PA6) and reinforced polyamide with 30% of glass fibers (PA66-GF30) using cemented carbide (K20) tool have been carried out. The experiments have been planned as per full factorial design of experiments. The effects of spindle speed, feed rate, and point angle on hole quality such as hole diameter and circularity error; the machinability characteristics such as thrust force and specific cutting coefficient have been analyzed by developing response surface methodology based second-order mathematical models. The parametric analysis shows that the quality of holes can be improved by proper selection of cutting parameters. The analysis also indicates the influence of reinforced fiber on proposed machinability characteristics during drilling of polyamides.

Research paper thumbnail of Optimization of Electrical Discharge Machining Process Parameters Using Desirability Approach

Applied Mechanics and Materials, 2012

In this paper, the application of the Taguchi method with fuzzy logic for optimizing the electric... more In this paper, the application of the Taguchi method with fuzzy logic for optimizing the electrical discharge machining process with multiple performance characteristics has been reported. A multi-response performance index is used to solve the electrical discharge machining process with multiple performance characteristics. The machining parameters (the workpiece polarity, pulse-on time, duty factor, open discharge voltage, discharge current and dielectric¯uid) are optimized with considerations of the multiple performance characteristics (electrode wear ratio and material removal rate). Experimental results are presented to demonstrate the effectiveness of this approach. #

Research paper thumbnail of Prediction of cutting forces during turning PA66 GF-30 glass fiber reinforced polyamide by soft computing techniques

Materials Science Forum, 2013

In the present paper the influence of the main cutting parameters on process performance during l... more In the present paper the influence of the main cutting parameters on process performance during longitudinal turning of PA66 GF-30 Glass Fiber Reinforced Polyamide is investigated. The selected cutting parameters are cutting speed and feed-rate whilst depth of cut is kept constant. As outputs (responses), cutting force components F t , F V and F r were selected. Test specimens in the form of round bars and cemented carbide cutting tool were used during the experimental process. Fifteen experiments were conducted having all different combinations of cutting parameter values. Analysis of Variance (ANOVA), statistical approaches and soft computing techniques (artificial neural network) were applied in order to formulate stochastic models for relating the responses with main cutting parameters. The results obtained, indicate that the proposed soft computing techniques can be effectively used to predict the cutting force components (F t , F V and F r ) thus; facilitating decision making during process planning since costly and time-consuming experimentation can be avoided.