Moises Deguchi Batista - Academia.edu (original) (raw)
Papers by Moises Deguchi Batista
Cerebral palsy (CP) is considered the most common physical disability in childhood. This disease ... more Cerebral palsy (CP) is considered the most common physical disability in childhood. This disease profoundly affects the health and well-being of its subjects and can influence multiple aspects of their caregivers, especially mothers. The objective of this study was evaluating the effect of a resistance exercises program on health related quality of life (HRQoL), burden perception and intensity of depressive symptoms of mothers of children and adolescents with CP. Twenty-two sedentary mothers able to practice resistance exercises program, caring for children and adolescents with CP, participated in a resistance exercises program, in 2 sessions per week during 12 weeks, with moderate intensity. All participants answered to the HRQoL questionnaires SF-36, Caregiver Burden Scale (CBS) and Beck Depression Inventory (BDI) before and after the intervention program. The scores obtained in the questionnaires before and after the intervention were compared using the Wilcoxon test and the magnitude of the differences was measured by effect size. The median age of the mothers was 41 years, ranging from 18 to 58 years. The median age of children and adolescents was 14 years, ranging from 3 to 21 years. The SF-36 scores were significantly higher after the intervention (p <0.05), except in role physical and role emotional domains, which already scored the highest value before the intervention. CBS and BDI scores were significantly reduced after intervention (p <0.05). The results showed that the regular practice of resistance exercise has a positive impact in HRQoL, burden perception and intensity of depressive symptoms of mothers caregivers of children and adolescents with PC.
Metals, 2022
Surface texturing is used in many applications to control the friction and wear behaviour of mech... more Surface texturing is used in many applications to control the friction and wear behaviour of mechanical components. The benefits of texture design on the tribological behaviour of conformal surfaces are well known. However, there is a big dependency between the geometrical features of the texture and the texture’s performance. In this paper, the effect of laser texturing parameters on textured geometrical features is studied, as well as its role in the tribological behaviour of AISI 630 steel under lubrication and high-contact pressure conditions. The results show a linear impact of the energy density on the surface quality, whereas the scanning speed influences the homogeneity of the sample. Nevertheless, the surface integrity is also affected by the laser parameters, reducing the micro-hardness on the textured area by up to 33%. Friction coefficient average values and stability presented high variations depending on the sample parameters. Finally, the wear mechanisms were analysed...
Materials, 2020
The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns bus... more The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns business leaders in all manufacturing sectors because of the importance that the Supply Chain has as a transversal tool and due to the leading role that it has been playing lately. Of all the manufacturing sectors, this study focuses on the aerospace, shipbuilding, and automotive sectors identified as transport. The present study carries out a descriptive review of existing publications in these three sectors in relation to the sustainability of the Supply Chain in its 4.0 adaptation as an update in matters that are in constant evolution. Among the results obtained, Lean practices are common to the three sectors, as well as different technologies focused on sustainability. Furthermore, the results show that the automotive sector is the one that makes the greatest contribution in this sense through collaborative programs that can be very useful to the other two sectors, thus benefiting from ...
Metals, 2020
The joining of dissimilar materials in a hybrid structure is a line of research of great interest... more The joining of dissimilar materials in a hybrid structure is a line of research of great interest at present. Nevertheless, the machining of materials with different machinability requires specific processes capable of minimizing defectology in both materials and achieving a correct surface finish in terms of functional performance. In this article, abrasive water jet machining of a hybrid carbon fiber-reinforced thermoplastics (CFRTP)/Steel structure and the generated surface finish are studied. A parametric study in two stacking configurations (CFRTP/Steel and Steel/CFRTP) has been established in order to determine the range of cutting parameters that generates the lowest values in terms of arithmetic mean roughness (Ra) and maximum profile height (Rz). The percentage contribution of each cutting parameter has been identified through an ANOVA analysis for each material and stacking configuration. A combination of 420 MPa hydraulic pressure with an abrasive mass flow of 385 g/min a...
Polymers, 2020
The development of high-complexity geometry parts is one of the main goals of additive manufactur... more The development of high-complexity geometry parts is one of the main goals of additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single-step method to join metals for years. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and which are more sensitive to thermal effects. In addition, the possibility of transmitting the laser beam through transparent polymer layers allows to us focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology....
The development of high complexity geometry parts is one of the main goals of the additive manufa... more The development of high complexity geometry parts is one of the main goals of the additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single step method to join metals until years ago. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and more sensitive to thermal effects. Also, the possibility of transmitting the laser beam through transparent polymer layers allows to focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology. In order ...
Sustainability, 2020
The supply chain is currently taking on a very important role in organizations seeking to improve... more The supply chain is currently taking on a very important role in organizations seeking to improve the competitiveness and profitability of the company. Its transversal character mainly places it in an unbeatable position to achieve this role. This article, through a study of each of the key enabling technologies of Industry 4.0, aims to obtain a general overview of the current state of the art in shipbuilding adapted to these technologies. To do so, a systematic review of what the scientific community says is carried out, dividing each of the technologies into different categories. In addition, the global vision of countries interested in each of the enabling technologies is also studied. Both studies present a general vision to the companies of the concerns of the scientific community, thus encouraging research on the subject that is focused on the sustainability of the shipbuilding supply chain.
Materials, 2020
This paper presents a preliminary study of aluminium matrix composite materials during machining,... more This paper presents a preliminary study of aluminium matrix composite materials during machining, with a special focus on their behavior under conventional processes. This work will expand the knowledge of these materials, which is considered to be strategic for some industrial sectors, such as the aeronautics, electronics, and automotive sectors. Finding a machining model will allow us to define the necessary parameters when applying the materials to industry. As a previous step of the material and its machining, an experimental state-of-the-art review has been carried out, revealing a lack of studies about the composition and material properties, processes, tools, and recommended parameters. The results obtained and reflected in this paper are as follows; SiC is present in metallic matrix composite (MMC) materials in a very wide variety of sizes. A metallographic study of the material confirms the high percentage of reinforcement and very high microhardness values registered. Duri...
Metals, 2020
Surface modification by different technologies prior to joining operations or improving tribologi... more Surface modification by different technologies prior to joining operations or improving tribological properties is a point of great interest. Improving surface activation by increasing the roughness of the metal is a relationship that is becoming more defined. In turn, an increase in surface wettability by evaluating contact angles indicates surface activation by obtaining a high surface free energy. Technologies such as shot blasting and laser surface texturing (LST) have generated several scientific studies where they have identified the influence of parameters on the formation of rough surfaces with defined patterns. However, the application of abrasive water jet texturing (AWJT) has been little studied as an alternative. This article compares these technologies in the texturing of a carbon steel s275 in order to identify the relationship between surface quality and surface activation. It has been determined that AWJT produces the highest Rt values close to 64 µm with a cross fee...
Materials, 2019
Carbon fiber-reinforced thermoplastics (CFRTPs) are materials of great interest in industry. Like... more Carbon fiber-reinforced thermoplastics (CFRTPs) are materials of great interest in industry. Like thermosets composite materials, they have an excellent weight/mechanical properties ratio and a high degree of automation in their manufacture and recyclability. However, these materials present difficulties in their machining due to their nature. Their anisotropy, together with their low glass transition temperature, can produce important defects in their machining. A process able to machine these materials correctly by producing very small thermal defects is abrasive waterjet machining. However, the dispersion of the waterjet produces a reduction in kinetic energy, which decreases its cutting capacity. This results in an inherent defect called a kerf taper. Also, machining these materials with reduced thicknesses can increase this defect due to the formation of a damage zone at the beginning of cut due to the abrasive particles. This paper studies the influence of cutting parameters o...
Materials, 2019
The shipbuilding industry shows a special interest in adapting to the changes proposed by the ind... more The shipbuilding industry shows a special interest in adapting to the changes proposed by the industry 4.0. This article bets on the development of an index that indicates the current situation considering that supply chain is a key factor in any type of change, and at the same time it serves as a control tool in the implementation of improvements. The proposed indices provide a first definition of the paradigm or paradigms that best fit the supply chain in order to improve its sustainability and a second definition, regarding the key enabling technologies for Industry 4.0. The values obtained put shipbuilding on the road to industry 4.0 while suggesting categorized planning of technologies.
Light alloys machining is a widely implemented process that have usually used in presence of cutt... more Light alloys machining is a widely implemented process that have usually used in presence of cutting fluids to reduce the wear impact and increase tool life. However, current environmental protection policies require their elimination in order to improve process sustainability. This fact forces to work under aggressive cutting conditions, producing adhesion wear that affects the integrity of the part surface. This study describes cutting tool wear mechanisms in machining of UNS A92024 samples under dry cutting conditions. EDS analysis showed the different composition of the adhered layers, while roughness was also positively affected by the change of the cutting geometry produced in the tool.
Polymers, 2019
The application of techniques to improve the surface finish of pieces obtained by fused depositio... more The application of techniques to improve the surface finish of pieces obtained by fused deposition modelling, as well as other functional aspects, is of great interest nowadays. Polylactic acid, a biodegradable material, has been considered a possible substitute for petroleum-based polymers. In this work, different chemical post-processing methods are applied to polylactic acid pieces obtained by fused deposition modelling and some characteristics are studied. Structural, thermal, and crystallinity property changes are analyzed according to the treatments applied. This can prevent degradation, eliminate the glass transition phase of the material, and thereby increase the thermal resistance by about 50 °C. An improvement in the roughness of the pieces of up to 97% was also found.
Materials, 2018
Additive manufacturing technologies play an important role in Industry 4.0. One of the most preva... more Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature.
Materials, 2018
One of the main criteria for the establishment of the performance of a forming process by materia... more One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of the process. This experimental research is focused on the application of Pin-on-Disc wear tests, in which the tribological interference between UNS A92024-T3 Aluminum–Copper alloy and tungsten carbide (WC–Co) has been studied. The main objective of this study is focused on the determination of the predominant wear mechanisms involved in the process, as well as the characterization of the sliding and friction effects by using SEM and Energy Dispersion Spectroscopy (EDS) techniques, as applied to WC–Co (cutting tool material)/Al (workpiece material) which are widely used in the aerospace industry. Performed analysis prove the appearance of abrasive wear mechanisms prior to adhesion. This fact promotes adhesion mechanisms in sev...
Materials, 2018
The aeronautics industry’s competitiveness has led to the need to increase productivity with one ... more The aeronautics industry’s competitiveness has led to the need to increase productivity with one shot drilling (OSD) systems capable of drilling stacks of dissimilar materials (fibre/metal laminates, FML) in order to reduce riveting times. Among the materials that constitute the current aeronautical models, composite materials and aluminium (Al) and titanium (Ti) alloys stand out. These one-pass machining techniques produce high-quality holes, especially when all the elements that have to be joined are made of the same material. This work has followed a conventional OSD strategy and the same cutting conditions applied to CFRP (carbo-fibre-reinforced polymer), Al and CFRP/Al stacked sheets to know the wear mechanisms produced. With this purpose, results were obtained by using current specific techniques, such as microstructural analysis, monitoring of the shear forces and analysis of macrogeometric deviations. It has been determined that when these drilling techniques are applied und...
Secondary tool adhesion wear is commonly provoked by two effects, whose nature depends on the pla... more Secondary tool adhesion wear is commonly provoked by two effects, whose nature depends on the placement of the adhered material. The so-called Built-Up Layer (BUL) is formed on the tool rake face and the Built-Up Edge (BUE) is developed on the cutting tool edge. These effects can be developed by different causes depending on both the cutting conditions and the material to be machined. In this work, X-Ray Photoelectron Spectroscopy (XPS) has been used to analyze the built-up layers formed during the dry drilling processes of aeronautical Ti-6Al-4V alloy. Changes in the Ti oxidation state in each layer have allowed proposing a BUL formation mechanism based on chemical reactions of the workpiece material during the drilling process. Effects of these reactions have been contrasted through the XPS analysis of the chip generated in the process. In parallel, SEM and EDS have been used as complementary techniques for obtaining further information about the BUL nature.
In the most of machining processes, chip morphology and microstructure contain deep information a... more In the most of machining processes, chip morphology and microstructure contain deep information about the cutting mechanisms, their evolution and, even, about both the process and the workpiece. However, usually, changes in the process are related only to changes in the tool morphology and in the surface integrity hiding relevant information. This is commonly due to the chip characterization is not an easy task. In effect, chip geometry and dimensional features are habitually hardly measurable and evaluable. In this work, a methodology for characterizing the chip developed in the dry turning processes of Titanium alloys (Ti6Al4V-UNS R56400) has been proposed. This characterization has been achieved by considering different geometrical and dimensional parameters. Thus, shrinkage parameter has been evaluated through the changes in length and compared with the corresponding values determined through variations measured in thickness and width. However, the partially discontinuous form of the Ti chips makes difficult the dimensional evaluation. Stereoscopic Optical Microscopy (SOM) techniques can help to evaluate the chip shrinkage parameter through the measurement of the shear angle. In parallel, SOM techniques can assist for measuring other geometrical parameters of the chip. In this context, the evolution of the shrinkage parameter with the length of machining and the changes of the chip geometry with the cutting parameters (cutting speed and feed) has been also analyzed.
Advanced Materials Research, 2012
Minimizing downtime in machine tools is one of the factors that determine the performance increas... more Minimizing downtime in machine tools is one of the factors that determine the performance increase of the production processes involved. This increase can be considered from different points of view: economic, energetic and environmental. Machining processes can be stopped by needing to change the tool as a consequence of the loss of their initial properties due to the wear process that suffer during machining. One of the wear processes which takes place in a wider range of temperatures in the machining of metal alloys is the adhesion wear, and specially in the case of light alloys, secondary adhesion wear, which can be placed in the tool rake face as a layer (Built-Up Layer, BUL) and in the tool edge (Built-Up Edge, BUE). This paper analyzes the influence of cutting parameters on the secondary adhesion wear effects in the dry turning of UNS A92024 (Al-Cu) alloy.
Advanced Materials Research, 2010
In this work, Stereoscopic Optical Microscopy (SOM), Scanning Electron Microscopy (SEM) and Energ... more In this work, Stereoscopic Optical Microscopy (SOM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) have been applied for analyzing the evolution of tool wear during the dry turning process of aerospace Al-Cu alloys. The results derived from this analysis have revealed that secondary adhesion is the main tool wear mechanism that takes place in such process. So, in the first instants of the machining process, a Built-Up Layer (BUL) is developed onto the tool rake face by thermomechanical causes, promoting the conditions for developing a Built-Up Edge (BUE) which grows to a critical size. Starting from it, BUE is extruded giving rise to secondary BUL-BUE effects. When these are removed, tool particles are dragged out provoking the tool wear.
Cerebral palsy (CP) is considered the most common physical disability in childhood. This disease ... more Cerebral palsy (CP) is considered the most common physical disability in childhood. This disease profoundly affects the health and well-being of its subjects and can influence multiple aspects of their caregivers, especially mothers. The objective of this study was evaluating the effect of a resistance exercises program on health related quality of life (HRQoL), burden perception and intensity of depressive symptoms of mothers of children and adolescents with CP. Twenty-two sedentary mothers able to practice resistance exercises program, caring for children and adolescents with CP, participated in a resistance exercises program, in 2 sessions per week during 12 weeks, with moderate intensity. All participants answered to the HRQoL questionnaires SF-36, Caregiver Burden Scale (CBS) and Beck Depression Inventory (BDI) before and after the intervention program. The scores obtained in the questionnaires before and after the intervention were compared using the Wilcoxon test and the magnitude of the differences was measured by effect size. The median age of the mothers was 41 years, ranging from 18 to 58 years. The median age of children and adolescents was 14 years, ranging from 3 to 21 years. The SF-36 scores were significantly higher after the intervention (p <0.05), except in role physical and role emotional domains, which already scored the highest value before the intervention. CBS and BDI scores were significantly reduced after intervention (p <0.05). The results showed that the regular practice of resistance exercise has a positive impact in HRQoL, burden perception and intensity of depressive symptoms of mothers caregivers of children and adolescents with PC.
Metals, 2022
Surface texturing is used in many applications to control the friction and wear behaviour of mech... more Surface texturing is used in many applications to control the friction and wear behaviour of mechanical components. The benefits of texture design on the tribological behaviour of conformal surfaces are well known. However, there is a big dependency between the geometrical features of the texture and the texture’s performance. In this paper, the effect of laser texturing parameters on textured geometrical features is studied, as well as its role in the tribological behaviour of AISI 630 steel under lubrication and high-contact pressure conditions. The results show a linear impact of the energy density on the surface quality, whereas the scanning speed influences the homogeneity of the sample. Nevertheless, the surface integrity is also affected by the laser parameters, reducing the micro-hardness on the textured area by up to 33%. Friction coefficient average values and stability presented high variations depending on the sample parameters. Finally, the wear mechanisms were analysed...
Materials, 2020
The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns bus... more The search for sustainability in the Supply Chain (SC) is one of the tasks that most concerns business leaders in all manufacturing sectors because of the importance that the Supply Chain has as a transversal tool and due to the leading role that it has been playing lately. Of all the manufacturing sectors, this study focuses on the aerospace, shipbuilding, and automotive sectors identified as transport. The present study carries out a descriptive review of existing publications in these three sectors in relation to the sustainability of the Supply Chain in its 4.0 adaptation as an update in matters that are in constant evolution. Among the results obtained, Lean practices are common to the three sectors, as well as different technologies focused on sustainability. Furthermore, the results show that the automotive sector is the one that makes the greatest contribution in this sense through collaborative programs that can be very useful to the other two sectors, thus benefiting from ...
Metals, 2020
The joining of dissimilar materials in a hybrid structure is a line of research of great interest... more The joining of dissimilar materials in a hybrid structure is a line of research of great interest at present. Nevertheless, the machining of materials with different machinability requires specific processes capable of minimizing defectology in both materials and achieving a correct surface finish in terms of functional performance. In this article, abrasive water jet machining of a hybrid carbon fiber-reinforced thermoplastics (CFRTP)/Steel structure and the generated surface finish are studied. A parametric study in two stacking configurations (CFRTP/Steel and Steel/CFRTP) has been established in order to determine the range of cutting parameters that generates the lowest values in terms of arithmetic mean roughness (Ra) and maximum profile height (Rz). The percentage contribution of each cutting parameter has been identified through an ANOVA analysis for each material and stacking configuration. A combination of 420 MPa hydraulic pressure with an abrasive mass flow of 385 g/min a...
Polymers, 2020
The development of high-complexity geometry parts is one of the main goals of additive manufactur... more The development of high-complexity geometry parts is one of the main goals of additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single-step method to join metals for years. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and which are more sensitive to thermal effects. In addition, the possibility of transmitting the laser beam through transparent polymer layers allows to us focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology....
The development of high complexity geometry parts is one of the main goals of the additive manufa... more The development of high complexity geometry parts is one of the main goals of the additive manufacturing technology. However, the failure of printed structures and the joining of different parts to create complex assemblies represents a real challenge in the research of efficient and sustainability techniques for the permanent assembly of polymers. Laser welding processes have been used as a single step method to join metals until years ago. Nowadays, the growing trend in the use of thermoplastics for additive manufacturing has led to the need to adapt this technique to materials with a very specific nature and more sensitive to thermal effects. Also, the possibility of transmitting the laser beam through transparent polymer layers allows to focus the energy supply on internal sections of the assembled components. In this research, an infrared laser marking system was used to join two different samples of polylactic acid manufactured by fused deposited modeling technology. In order ...
Sustainability, 2020
The supply chain is currently taking on a very important role in organizations seeking to improve... more The supply chain is currently taking on a very important role in organizations seeking to improve the competitiveness and profitability of the company. Its transversal character mainly places it in an unbeatable position to achieve this role. This article, through a study of each of the key enabling technologies of Industry 4.0, aims to obtain a general overview of the current state of the art in shipbuilding adapted to these technologies. To do so, a systematic review of what the scientific community says is carried out, dividing each of the technologies into different categories. In addition, the global vision of countries interested in each of the enabling technologies is also studied. Both studies present a general vision to the companies of the concerns of the scientific community, thus encouraging research on the subject that is focused on the sustainability of the shipbuilding supply chain.
Materials, 2020
This paper presents a preliminary study of aluminium matrix composite materials during machining,... more This paper presents a preliminary study of aluminium matrix composite materials during machining, with a special focus on their behavior under conventional processes. This work will expand the knowledge of these materials, which is considered to be strategic for some industrial sectors, such as the aeronautics, electronics, and automotive sectors. Finding a machining model will allow us to define the necessary parameters when applying the materials to industry. As a previous step of the material and its machining, an experimental state-of-the-art review has been carried out, revealing a lack of studies about the composition and material properties, processes, tools, and recommended parameters. The results obtained and reflected in this paper are as follows; SiC is present in metallic matrix composite (MMC) materials in a very wide variety of sizes. A metallographic study of the material confirms the high percentage of reinforcement and very high microhardness values registered. Duri...
Metals, 2020
Surface modification by different technologies prior to joining operations or improving tribologi... more Surface modification by different technologies prior to joining operations or improving tribological properties is a point of great interest. Improving surface activation by increasing the roughness of the metal is a relationship that is becoming more defined. In turn, an increase in surface wettability by evaluating contact angles indicates surface activation by obtaining a high surface free energy. Technologies such as shot blasting and laser surface texturing (LST) have generated several scientific studies where they have identified the influence of parameters on the formation of rough surfaces with defined patterns. However, the application of abrasive water jet texturing (AWJT) has been little studied as an alternative. This article compares these technologies in the texturing of a carbon steel s275 in order to identify the relationship between surface quality and surface activation. It has been determined that AWJT produces the highest Rt values close to 64 µm with a cross fee...
Materials, 2019
Carbon fiber-reinforced thermoplastics (CFRTPs) are materials of great interest in industry. Like... more Carbon fiber-reinforced thermoplastics (CFRTPs) are materials of great interest in industry. Like thermosets composite materials, they have an excellent weight/mechanical properties ratio and a high degree of automation in their manufacture and recyclability. However, these materials present difficulties in their machining due to their nature. Their anisotropy, together with their low glass transition temperature, can produce important defects in their machining. A process able to machine these materials correctly by producing very small thermal defects is abrasive waterjet machining. However, the dispersion of the waterjet produces a reduction in kinetic energy, which decreases its cutting capacity. This results in an inherent defect called a kerf taper. Also, machining these materials with reduced thicknesses can increase this defect due to the formation of a damage zone at the beginning of cut due to the abrasive particles. This paper studies the influence of cutting parameters o...
Materials, 2019
The shipbuilding industry shows a special interest in adapting to the changes proposed by the ind... more The shipbuilding industry shows a special interest in adapting to the changes proposed by the industry 4.0. This article bets on the development of an index that indicates the current situation considering that supply chain is a key factor in any type of change, and at the same time it serves as a control tool in the implementation of improvements. The proposed indices provide a first definition of the paradigm or paradigms that best fit the supply chain in order to improve its sustainability and a second definition, regarding the key enabling technologies for Industry 4.0. The values obtained put shipbuilding on the road to industry 4.0 while suggesting categorized planning of technologies.
Light alloys machining is a widely implemented process that have usually used in presence of cutt... more Light alloys machining is a widely implemented process that have usually used in presence of cutting fluids to reduce the wear impact and increase tool life. However, current environmental protection policies require their elimination in order to improve process sustainability. This fact forces to work under aggressive cutting conditions, producing adhesion wear that affects the integrity of the part surface. This study describes cutting tool wear mechanisms in machining of UNS A92024 samples under dry cutting conditions. EDS analysis showed the different composition of the adhered layers, while roughness was also positively affected by the change of the cutting geometry produced in the tool.
Polymers, 2019
The application of techniques to improve the surface finish of pieces obtained by fused depositio... more The application of techniques to improve the surface finish of pieces obtained by fused deposition modelling, as well as other functional aspects, is of great interest nowadays. Polylactic acid, a biodegradable material, has been considered a possible substitute for petroleum-based polymers. In this work, different chemical post-processing methods are applied to polylactic acid pieces obtained by fused deposition modelling and some characteristics are studied. Structural, thermal, and crystallinity property changes are analyzed according to the treatments applied. This can prevent degradation, eliminate the glass transition phase of the material, and thereby increase the thermal resistance by about 50 °C. An improvement in the roughness of the pieces of up to 97% was also found.
Materials, 2018
Additive manufacturing technologies play an important role in Industry 4.0. One of the most preva... more Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature.
Materials, 2018
One of the main criteria for the establishment of the performance of a forming process by materia... more One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of the process. This experimental research is focused on the application of Pin-on-Disc wear tests, in which the tribological interference between UNS A92024-T3 Aluminum–Copper alloy and tungsten carbide (WC–Co) has been studied. The main objective of this study is focused on the determination of the predominant wear mechanisms involved in the process, as well as the characterization of the sliding and friction effects by using SEM and Energy Dispersion Spectroscopy (EDS) techniques, as applied to WC–Co (cutting tool material)/Al (workpiece material) which are widely used in the aerospace industry. Performed analysis prove the appearance of abrasive wear mechanisms prior to adhesion. This fact promotes adhesion mechanisms in sev...
Materials, 2018
The aeronautics industry’s competitiveness has led to the need to increase productivity with one ... more The aeronautics industry’s competitiveness has led to the need to increase productivity with one shot drilling (OSD) systems capable of drilling stacks of dissimilar materials (fibre/metal laminates, FML) in order to reduce riveting times. Among the materials that constitute the current aeronautical models, composite materials and aluminium (Al) and titanium (Ti) alloys stand out. These one-pass machining techniques produce high-quality holes, especially when all the elements that have to be joined are made of the same material. This work has followed a conventional OSD strategy and the same cutting conditions applied to CFRP (carbo-fibre-reinforced polymer), Al and CFRP/Al stacked sheets to know the wear mechanisms produced. With this purpose, results were obtained by using current specific techniques, such as microstructural analysis, monitoring of the shear forces and analysis of macrogeometric deviations. It has been determined that when these drilling techniques are applied und...
Secondary tool adhesion wear is commonly provoked by two effects, whose nature depends on the pla... more Secondary tool adhesion wear is commonly provoked by two effects, whose nature depends on the placement of the adhered material. The so-called Built-Up Layer (BUL) is formed on the tool rake face and the Built-Up Edge (BUE) is developed on the cutting tool edge. These effects can be developed by different causes depending on both the cutting conditions and the material to be machined. In this work, X-Ray Photoelectron Spectroscopy (XPS) has been used to analyze the built-up layers formed during the dry drilling processes of aeronautical Ti-6Al-4V alloy. Changes in the Ti oxidation state in each layer have allowed proposing a BUL formation mechanism based on chemical reactions of the workpiece material during the drilling process. Effects of these reactions have been contrasted through the XPS analysis of the chip generated in the process. In parallel, SEM and EDS have been used as complementary techniques for obtaining further information about the BUL nature.
In the most of machining processes, chip morphology and microstructure contain deep information a... more In the most of machining processes, chip morphology and microstructure contain deep information about the cutting mechanisms, their evolution and, even, about both the process and the workpiece. However, usually, changes in the process are related only to changes in the tool morphology and in the surface integrity hiding relevant information. This is commonly due to the chip characterization is not an easy task. In effect, chip geometry and dimensional features are habitually hardly measurable and evaluable. In this work, a methodology for characterizing the chip developed in the dry turning processes of Titanium alloys (Ti6Al4V-UNS R56400) has been proposed. This characterization has been achieved by considering different geometrical and dimensional parameters. Thus, shrinkage parameter has been evaluated through the changes in length and compared with the corresponding values determined through variations measured in thickness and width. However, the partially discontinuous form of the Ti chips makes difficult the dimensional evaluation. Stereoscopic Optical Microscopy (SOM) techniques can help to evaluate the chip shrinkage parameter through the measurement of the shear angle. In parallel, SOM techniques can assist for measuring other geometrical parameters of the chip. In this context, the evolution of the shrinkage parameter with the length of machining and the changes of the chip geometry with the cutting parameters (cutting speed and feed) has been also analyzed.
Advanced Materials Research, 2012
Minimizing downtime in machine tools is one of the factors that determine the performance increas... more Minimizing downtime in machine tools is one of the factors that determine the performance increase of the production processes involved. This increase can be considered from different points of view: economic, energetic and environmental. Machining processes can be stopped by needing to change the tool as a consequence of the loss of their initial properties due to the wear process that suffer during machining. One of the wear processes which takes place in a wider range of temperatures in the machining of metal alloys is the adhesion wear, and specially in the case of light alloys, secondary adhesion wear, which can be placed in the tool rake face as a layer (Built-Up Layer, BUL) and in the tool edge (Built-Up Edge, BUE). This paper analyzes the influence of cutting parameters on the secondary adhesion wear effects in the dry turning of UNS A92024 (Al-Cu) alloy.
Advanced Materials Research, 2010
In this work, Stereoscopic Optical Microscopy (SOM), Scanning Electron Microscopy (SEM) and Energ... more In this work, Stereoscopic Optical Microscopy (SOM), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) have been applied for analyzing the evolution of tool wear during the dry turning process of aerospace Al-Cu alloys. The results derived from this analysis have revealed that secondary adhesion is the main tool wear mechanism that takes place in such process. So, in the first instants of the machining process, a Built-Up Layer (BUL) is developed onto the tool rake face by thermomechanical causes, promoting the conditions for developing a Built-Up Edge (BUE) which grows to a critical size. Starting from it, BUE is extruded giving rise to secondary BUL-BUE effects. When these are removed, tool particles are dragged out provoking the tool wear.