Gaur egungo gizarteak adimen logiko-matematikoari ematen dio garrantzi handia, beste adimen batzu... more Gaur egungo gizarteak adimen logiko-matematikoari ematen dio garrantzi handia, beste adimen batzuk baztertzen dituen bitartean. Hauen artean adimen kinestesikoa aurkitu dezakegu, Gorputz Hezkuntzaren bitartez landu ohi dena. Lan honen helburua, matematikaren eta Gorputz Hezkuntzaren arteko batura posiblea dela ikustaraztea da, osagarri direla baieztatzen duten ikerketetaz baliatuta. Berrikuspen bibliografiko honetan diziplinartekotasunean eragina duten kontzeptuak azalduko dira baita honen onurak eta hauek aprobetxatzeko jarduerak ere. HITZ GAKOAK: diziplinartekotasuna, matematika, Gorputz Hezkuntza, Lehen Hezkuntza. RESUMEN La sociedad de hoy en día da mucha importancia a la inteligencia lógico-matemática mientras deja de lado otras inteligencias como puede ser la inteligencia corporal kinestésica, habitualmente trabajada en la Educación Física. El objetivo de este trabajo es hacer ver que es posible trabajar las matemáticas y la Educación Física de manera conjunta. Esto será respaldado por datos y estudios científicos que prueban la mejora en dichos ámbitos cuando son trabajados conjuntamente (interdisciplinariedad). En esta revisión bibliográfica se explicarán conceptos relacionados con ello, al igual que se hablará de las ventajas de la interdisciplinariedad y de actividades para poder beneficiarse de ellas.
Journal of Materials Research and Technology, 2021
Wire and Arc Additive Manufacturing has the potential to become an appropriate technique to produ... more Wire and Arc Additive Manufacturing has the potential to become an appropriate technique to produce large complex-shaped metallic parts. However, a post-processing machining operation is necessary to reach the final geometry. In this work, Inconel 718 walls were manufactured in a monitored environment and their microstructure and mechanical properties were characterised. Then, slot milling operations were performed to investigate the influence of cutting speed and machining direction. The conclusions drawn from this article can be used as a guide for a correct definition of strategies and milling parameters. It was observed that at higher cutting speeds a better surface quality and lower torques are obtained. Moreover, the main novelty of this work is that is shows the influence of the anisotropy of WAAM-Inconel 718 on its machinability. Milling along the torch's travel direction offers better dimensional tolerance values with lower cutting torques, being more favourable than machining in the building direction.
A challenge in drilling polymers is their very low melting point, especially when holes with a la... more A challenge in drilling polymers is their very low melting point, especially when holes with a large length-to-diameter ratio are required. One opportunity to avoid chip accumulation is the use of low vibration assisted drilling. In the present work, the comprehensive knowledge acquired from the machining of metals is transferred to drilling of polycarbonate PC1000. The first research objective of this work was to evaluate if the kinematic models proposed in literature could predict the onset of discontinuous chip generation. To do so, a series of drilling tests were performed with a MITIS tool holder varying vibration amplitude and hole length. During the tests, thrust force and workpiece temperature were registered and, afterwards, hole diameter and surface roughness were measured. The results showed that a kinematic model can be useful to predict the onset of discontinuous chip generation. It was also concluded that surface roughness increases with vibration amplitude until the onset of chip breakage is reached. Furthermore, a correlation between temperature and surface roughness was detected. Regarding cutting forces, a relationship was observed between the thrust force signal amplitude and the amplitude vibration of the MITIS tool-holder. This correlation could be useful to calibrate other future designs of tool holders.
In the current days, the new range of machine tools allows the production of titanium alloy parts... more In the current days, the new range of machine tools allows the production of titanium alloy parts for the aeronautical sector through additive technologies. The quality of the materials produced is being studied extensively by the research community. This new manufacturing paradigm also opens important challenges such as the definition and analysis of the optimal strategies for finishing-oriented machining in this type of part. Researchers in both materials and manufacturing processes are making numerous advances in this field. This article discusses the analysis of the production and subsequent machining in the quality of TI6Al4V produced by Wire Arc Additive Manufacturing (WAAM), more specifically Plasma Arc Welding (PAW). The promising results observed make it a viable alternative to traditional manufacturing methods.
The manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ra... more The manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ratios. Production costs could be greatly reduced by the combination of an additive manufacturing (AM) process followed by a finishing machining operation. Among the different AM alternatives, wire arc additive manufacturing (WAAM) offers deposition rates of kg/h and could be the key for the production of parts of several meters economically. In this study, the influence of the manufacturing process of Ti6Al4V alloy on both its material properties and machinability is investigated. First, the mechanical properties of a workpiece obtained by WAAM were compared to those in a conventional laminated plate. Then, drilling tests were carried out in both materials. The results showed that WAAM leads to a higher hardness than laminated Ti6Al4V and satisfies the requirements of the standard in terms of mechanical properties. As a consequence, higher cutting forces, shorter chips, and lower burr hei...
Laser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing o... more Laser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing of near-net-shape products. This could mean significant savings in terms of materials and costs in the manufacturing of high-performance components for the aeronautical industry. In this work, an analysis of how the LMD processing of alloy 718 affects the final machining has been carried out. For this purpose, a comparative study has been done by means of the monitoring of the end milling process of a part manufactured by LMD and a rough-milled part from forged material. Differences between process outputs such as chip morphology and cutting forces were studied. Material characteristics such as microstructure, hardness and mechanical properties were also analyzed.
Hybrid stacks made of carbon reinforced plastic (CFRP) and Ti-6Al-4V alloy (Ti) are often drilled... more Hybrid stacks made of carbon reinforced plastic (CFRP) and Ti-6Al-4V alloy (Ti) are often drilled together to reduce positional errors, enhance tight tolerances and minimize machining time. However, this is a complex task due to the dissimilar properties of each material. Tool geometry has a significant impact on the machinability of CFRP/Ti stacks. In this study, the influence of flute number and stepped bit design was experimentally investigated. Confocal and SEM microscopy were used to analyse the evolution of the cutting-edge micro-geometry and the dominant wear modes. The results have shown that a stepped design with three flutes leads to a slower wear progression, lower cutting forces and less hole damage. Furthermore, this paper also highlights the influence of the geometrical characteristics of the stepped tool design on the drilling stage number and on the shape of the thrust force signal. The information gathered can be used for the improvement of the process competitiveness in terms of the reduction of production time and cost.
The International Journal of Advanced Manufacturing Technology, 2017
Austempered ductile iron (ADI) has a high potential to substitute alloy steels in power-train app... more Austempered ductile iron (ADI) has a high potential to substitute alloy steels in power-train applications. However, the machinability of ADI is difficult and tool life is shortened by the appearance of severe adhesive and abrasive wear on tool cutting edge. In this regard, the deposition of a suitable coating could reduce these phenomena. Previous works have investigated the behavior of coated tools on turning or drilling of ADI, but a knowledge gap exists regarding the tapping operation. In this study, the performance of six PVD coatings for the tapping of ADI-900 was investigated. The tools were coated using Cathodic Arc deposition and were analyzed in two sets of experiments. In the first set, four commercial coatings commonly used in cast iron machining were compared: a monolithic AlTiN, a nanostructured AlCrSiN, and two configurations of AlTiSiN (a multilayer and a gradient). Before film deposition, the high speed steel (HSS) substrate surface was micro-blasted. Cutting performance was evaluated by a combined analysis of tool wear, cutting torque data, and SEM-investigations of the tap surface. The best results were yielded by the gradient AlTiSiN (AlTiSiN-G) but coating delamination was also noticeable in the rake face. The application of a drag grinding pre-treatment led to an improvement of the coating adhesion and to a reduction of wear and torque values. In the second set of experiments, AlTiSiN-G was compared to a double layer TiAlCN-DLC coating and to AlTiSiN-18. The results confirmed that the use of HSS taps coated with AlTiSiN-G is a feasible solution for tapping of ADI-900.
Malignant central nervous system (CNS) tumors are the leading cause of death by cancer in childre... more Malignant central nervous system (CNS) tumors are the leading cause of death by cancer in children and the second commonest pediatric cancer type. Despite several decades of epidemiologic research, the etiology of childhood CNS tumors is still largely unknown. A few genetic syndromes and therapeutic ionizing radiation are thought to account for 5-10% of childhood cancer, but the etiology of other cases remains unknown. Nongenetic causes, like environmental agents, are thought to explain them. However, as very few epidemiologic studies have been conducted, it is not surprising that nongenetic risk factors have not been detected. The biggest difference between cancers for which there are good etiologic clues and those for which there are none could be the number of relevant studies. This study, which covers the 1980-2011 period, identified links between CNS cancer evolution and the socioeconomic and environmental indicators in the same space and time limits in the European Union.
International Journal of Machine Tools and Manufacture, 2015
The grind-hardening process uses the heat generated within the grinding zone in order to produce ... more The grind-hardening process uses the heat generated within the grinding zone in order to produce surface hardening of the workpiece. However, after the process, workpieces present dimensional inaccuracies and poor surface roughness. Thus, a final grinding operation has to be performed. For an industrial implementation of the whole process, two problems need to be solved. On the one hand, online control of the hardness penetration depth (HPD) should be achieved. On the other hand, excessive softening of the workpiece has to be avoided during the finishing grinding. This paper, firstly, investigates the feasibility of using the area based grinding energy (E ″ c) for the prediction of the HPD. Surface grind-hardening tests carried out on 100Cr6, 42CrMo4 and AISI 1045 steels have shown that, for all the tested parameter sets, a linear correlation exists between E ″ c and HPD. Furthermore, the slope of this linear relationship can be estimated from the chemical composition of the hardened steel based on the equivalent carbon number. On the other hand, the influence of varying wheel dressing conditions on the E ″ c-HPD relationship is analysed. Secondly, it has been found that a relationship exists between E ″ c and the surface softening during the finishing grinding operation. This relationship is independent of the grinding parameter combination when the maximum undeformed chip thickness is over a threshold value. Thus, E ″ c is a very appropriate parameter to control both the hardening and the finishing process of grind-hardened workpieces.
The International Journal of Advanced Manufacturing Technology, 2015
ABSTRACT Grind-hardening is a manufacturing process that uses the heat generated within the grind... more ABSTRACT Grind-hardening is a manufacturing process that uses the heat generated within the grinding zone in order to produce surface hardening. After the process, workpieces present dimensional inaccuracies and a poor surface finish. Thus, a finishing grinding operation has to be carried out. For a successful implementation of the whole process, two problems have to be solved. Firstly, the desired hardened depth has to be achieved in the hardening stage. Secondly, surface softening has to be controlled during the finishing stage. The objective of this work is to address the modelling of the whole process so that the experimental effort during its set up is reduced. To do this, firstly, a thermal model is developed for the estimation of the hardened depth. This model considers the heat evacuated by the chips in a simplified way and takes into account the heat consumed by the fast austenitization process through an original methodology. Secondly, a model is proposed for the estimation of surface softening during finishing grinding. A methodology is presented for the prediction of surface hardness under non-isothermal tempering. Both models are calibrated and validated for the AISI 1045 steel, and the predicted results are in agreement with the experimental data for the studied grinding regimes. In this regard, the grind-hardening model predicts the hardness penetration depth (HPD) precisely for HPD values over 0.2 mm. The finishing model estimates the surface hardness after the finishing of the workpiece with an error lower than 6 %.
Advances in Non Conventional Materials Processing Technologies, 2012
Grinding is a stochastic process applied in the last stages of the manufacturing cycle. In last d... more Grinding is a stochastic process applied in the last stages of the manufacturing cycle. In last decades, grinding research has focused on prediction of thermal damage on ground workpiece since it is of considerable importance from both research and industrial perspectives. A number of numerical and analytical thermal models have been carried out so far. However, new grinding processes such as peel grinding, creep feed grinding and others such as plongee grinding need new models which consider the effect of higher depth of cuts, but there is no information about the minimum depth of cut to consider the elimination of grounded material in FEM models. This article establishes the frontier from which the removed ground material should be physically eliminated to obtain an accurate FEM thermal model. Results show valuable information to decide which kind of model (with or without element elimination) is enough accurate for their purpose and application.
The International Journal of Advanced Manufacturing Technology, 2013
Grind-hardening is an innovative manufacturing process that takes advantage of the high amount of... more Grind-hardening is an innovative manufacturing process that takes advantage of the high amount of heat generated in the contact zone to produce a martensitic phase transformation in the subsurface layer of the workpiece. However, for a successful industrial implementation of the process, the closed loop control of the hardening depth is essential. Firstly, in this paper, cylindrical traverse grinding tests and metallographic analysis are conducted, and a grinding parameter that enables the in-process control of the hardness penetration depth (HPD) is proposed. Secondly, a nondestructive method based on the Barkhausen noise technique is presented as a quality control procedure for the HPD estimation. Keywords Grind-hardening. Cylindrical traverse grinding. Surface integrity. Barkhausen noise Abbreviations BN Barkhausen noise HPD Hardness penetration depth RMS Root mean square Nomenclature a e Depth of cut (mm) a f Axial feed per revolution (mm/revolution) b seff Effective width of cut (mm) d e Equivalent diameter (mm) e c Specific grinding energy (J/mm 3) E c ″ Area-specific grinding energy (J/mm 2) f Frequency of the BN signal (Hz) F t Tangential force (N) l g Length of contact (mm) P c ″ Area-specific grinding power (W/mm 2) v c Cutting speed (m/s) v f Axial feed rate (mm/min) v s Grinding wheel speed (m/s) v w Workpiece peripheral speed (m/s) σ Electrical conductivity (Ω −1 m −1) μ Magnetic permeability (T m A −1
Gaur egungo gizarteak adimen logiko-matematikoari ematen dio garrantzi handia, beste adimen batzu... more Gaur egungo gizarteak adimen logiko-matematikoari ematen dio garrantzi handia, beste adimen batzuk baztertzen dituen bitartean. Hauen artean adimen kinestesikoa aurkitu dezakegu, Gorputz Hezkuntzaren bitartez landu ohi dena. Lan honen helburua, matematikaren eta Gorputz Hezkuntzaren arteko batura posiblea dela ikustaraztea da, osagarri direla baieztatzen duten ikerketetaz baliatuta. Berrikuspen bibliografiko honetan diziplinartekotasunean eragina duten kontzeptuak azalduko dira baita honen onurak eta hauek aprobetxatzeko jarduerak ere. HITZ GAKOAK: diziplinartekotasuna, matematika, Gorputz Hezkuntza, Lehen Hezkuntza. RESUMEN La sociedad de hoy en día da mucha importancia a la inteligencia lógico-matemática mientras deja de lado otras inteligencias como puede ser la inteligencia corporal kinestésica, habitualmente trabajada en la Educación Física. El objetivo de este trabajo es hacer ver que es posible trabajar las matemáticas y la Educación Física de manera conjunta. Esto será respaldado por datos y estudios científicos que prueban la mejora en dichos ámbitos cuando son trabajados conjuntamente (interdisciplinariedad). En esta revisión bibliográfica se explicarán conceptos relacionados con ello, al igual que se hablará de las ventajas de la interdisciplinariedad y de actividades para poder beneficiarse de ellas.
Journal of Materials Research and Technology, 2021
Wire and Arc Additive Manufacturing has the potential to become an appropriate technique to produ... more Wire and Arc Additive Manufacturing has the potential to become an appropriate technique to produce large complex-shaped metallic parts. However, a post-processing machining operation is necessary to reach the final geometry. In this work, Inconel 718 walls were manufactured in a monitored environment and their microstructure and mechanical properties were characterised. Then, slot milling operations were performed to investigate the influence of cutting speed and machining direction. The conclusions drawn from this article can be used as a guide for a correct definition of strategies and milling parameters. It was observed that at higher cutting speeds a better surface quality and lower torques are obtained. Moreover, the main novelty of this work is that is shows the influence of the anisotropy of WAAM-Inconel 718 on its machinability. Milling along the torch's travel direction offers better dimensional tolerance values with lower cutting torques, being more favourable than machining in the building direction.
A challenge in drilling polymers is their very low melting point, especially when holes with a la... more A challenge in drilling polymers is their very low melting point, especially when holes with a large length-to-diameter ratio are required. One opportunity to avoid chip accumulation is the use of low vibration assisted drilling. In the present work, the comprehensive knowledge acquired from the machining of metals is transferred to drilling of polycarbonate PC1000. The first research objective of this work was to evaluate if the kinematic models proposed in literature could predict the onset of discontinuous chip generation. To do so, a series of drilling tests were performed with a MITIS tool holder varying vibration amplitude and hole length. During the tests, thrust force and workpiece temperature were registered and, afterwards, hole diameter and surface roughness were measured. The results showed that a kinematic model can be useful to predict the onset of discontinuous chip generation. It was also concluded that surface roughness increases with vibration amplitude until the onset of chip breakage is reached. Furthermore, a correlation between temperature and surface roughness was detected. Regarding cutting forces, a relationship was observed between the thrust force signal amplitude and the amplitude vibration of the MITIS tool-holder. This correlation could be useful to calibrate other future designs of tool holders.
In the current days, the new range of machine tools allows the production of titanium alloy parts... more In the current days, the new range of machine tools allows the production of titanium alloy parts for the aeronautical sector through additive technologies. The quality of the materials produced is being studied extensively by the research community. This new manufacturing paradigm also opens important challenges such as the definition and analysis of the optimal strategies for finishing-oriented machining in this type of part. Researchers in both materials and manufacturing processes are making numerous advances in this field. This article discusses the analysis of the production and subsequent machining in the quality of TI6Al4V produced by Wire Arc Additive Manufacturing (WAAM), more specifically Plasma Arc Welding (PAW). The promising results observed make it a viable alternative to traditional manufacturing methods.
The manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ra... more The manufacturing of titanium airframe parts involves significant machining and low buy-to-fly ratios. Production costs could be greatly reduced by the combination of an additive manufacturing (AM) process followed by a finishing machining operation. Among the different AM alternatives, wire arc additive manufacturing (WAAM) offers deposition rates of kg/h and could be the key for the production of parts of several meters economically. In this study, the influence of the manufacturing process of Ti6Al4V alloy on both its material properties and machinability is investigated. First, the mechanical properties of a workpiece obtained by WAAM were compared to those in a conventional laminated plate. Then, drilling tests were carried out in both materials. The results showed that WAAM leads to a higher hardness than laminated Ti6Al4V and satisfies the requirements of the standard in terms of mechanical properties. As a consequence, higher cutting forces, shorter chips, and lower burr hei...
Laser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing o... more Laser metal deposition (LMD) is an additive manufacturing process that allows the manufacturing of near-net-shape products. This could mean significant savings in terms of materials and costs in the manufacturing of high-performance components for the aeronautical industry. In this work, an analysis of how the LMD processing of alloy 718 affects the final machining has been carried out. For this purpose, a comparative study has been done by means of the monitoring of the end milling process of a part manufactured by LMD and a rough-milled part from forged material. Differences between process outputs such as chip morphology and cutting forces were studied. Material characteristics such as microstructure, hardness and mechanical properties were also analyzed.
Hybrid stacks made of carbon reinforced plastic (CFRP) and Ti-6Al-4V alloy (Ti) are often drilled... more Hybrid stacks made of carbon reinforced plastic (CFRP) and Ti-6Al-4V alloy (Ti) are often drilled together to reduce positional errors, enhance tight tolerances and minimize machining time. However, this is a complex task due to the dissimilar properties of each material. Tool geometry has a significant impact on the machinability of CFRP/Ti stacks. In this study, the influence of flute number and stepped bit design was experimentally investigated. Confocal and SEM microscopy were used to analyse the evolution of the cutting-edge micro-geometry and the dominant wear modes. The results have shown that a stepped design with three flutes leads to a slower wear progression, lower cutting forces and less hole damage. Furthermore, this paper also highlights the influence of the geometrical characteristics of the stepped tool design on the drilling stage number and on the shape of the thrust force signal. The information gathered can be used for the improvement of the process competitiveness in terms of the reduction of production time and cost.
The International Journal of Advanced Manufacturing Technology, 2017
Austempered ductile iron (ADI) has a high potential to substitute alloy steels in power-train app... more Austempered ductile iron (ADI) has a high potential to substitute alloy steels in power-train applications. However, the machinability of ADI is difficult and tool life is shortened by the appearance of severe adhesive and abrasive wear on tool cutting edge. In this regard, the deposition of a suitable coating could reduce these phenomena. Previous works have investigated the behavior of coated tools on turning or drilling of ADI, but a knowledge gap exists regarding the tapping operation. In this study, the performance of six PVD coatings for the tapping of ADI-900 was investigated. The tools were coated using Cathodic Arc deposition and were analyzed in two sets of experiments. In the first set, four commercial coatings commonly used in cast iron machining were compared: a monolithic AlTiN, a nanostructured AlCrSiN, and two configurations of AlTiSiN (a multilayer and a gradient). Before film deposition, the high speed steel (HSS) substrate surface was micro-blasted. Cutting performance was evaluated by a combined analysis of tool wear, cutting torque data, and SEM-investigations of the tap surface. The best results were yielded by the gradient AlTiSiN (AlTiSiN-G) but coating delamination was also noticeable in the rake face. The application of a drag grinding pre-treatment led to an improvement of the coating adhesion and to a reduction of wear and torque values. In the second set of experiments, AlTiSiN-G was compared to a double layer TiAlCN-DLC coating and to AlTiSiN-18. The results confirmed that the use of HSS taps coated with AlTiSiN-G is a feasible solution for tapping of ADI-900.
Malignant central nervous system (CNS) tumors are the leading cause of death by cancer in childre... more Malignant central nervous system (CNS) tumors are the leading cause of death by cancer in children and the second commonest pediatric cancer type. Despite several decades of epidemiologic research, the etiology of childhood CNS tumors is still largely unknown. A few genetic syndromes and therapeutic ionizing radiation are thought to account for 5-10% of childhood cancer, but the etiology of other cases remains unknown. Nongenetic causes, like environmental agents, are thought to explain them. However, as very few epidemiologic studies have been conducted, it is not surprising that nongenetic risk factors have not been detected. The biggest difference between cancers for which there are good etiologic clues and those for which there are none could be the number of relevant studies. This study, which covers the 1980-2011 period, identified links between CNS cancer evolution and the socioeconomic and environmental indicators in the same space and time limits in the European Union.
International Journal of Machine Tools and Manufacture, 2015
The grind-hardening process uses the heat generated within the grinding zone in order to produce ... more The grind-hardening process uses the heat generated within the grinding zone in order to produce surface hardening of the workpiece. However, after the process, workpieces present dimensional inaccuracies and poor surface roughness. Thus, a final grinding operation has to be performed. For an industrial implementation of the whole process, two problems need to be solved. On the one hand, online control of the hardness penetration depth (HPD) should be achieved. On the other hand, excessive softening of the workpiece has to be avoided during the finishing grinding. This paper, firstly, investigates the feasibility of using the area based grinding energy (E ″ c) for the prediction of the HPD. Surface grind-hardening tests carried out on 100Cr6, 42CrMo4 and AISI 1045 steels have shown that, for all the tested parameter sets, a linear correlation exists between E ″ c and HPD. Furthermore, the slope of this linear relationship can be estimated from the chemical composition of the hardened steel based on the equivalent carbon number. On the other hand, the influence of varying wheel dressing conditions on the E ″ c-HPD relationship is analysed. Secondly, it has been found that a relationship exists between E ″ c and the surface softening during the finishing grinding operation. This relationship is independent of the grinding parameter combination when the maximum undeformed chip thickness is over a threshold value. Thus, E ″ c is a very appropriate parameter to control both the hardening and the finishing process of grind-hardened workpieces.
The International Journal of Advanced Manufacturing Technology, 2015
ABSTRACT Grind-hardening is a manufacturing process that uses the heat generated within the grind... more ABSTRACT Grind-hardening is a manufacturing process that uses the heat generated within the grinding zone in order to produce surface hardening. After the process, workpieces present dimensional inaccuracies and a poor surface finish. Thus, a finishing grinding operation has to be carried out. For a successful implementation of the whole process, two problems have to be solved. Firstly, the desired hardened depth has to be achieved in the hardening stage. Secondly, surface softening has to be controlled during the finishing stage. The objective of this work is to address the modelling of the whole process so that the experimental effort during its set up is reduced. To do this, firstly, a thermal model is developed for the estimation of the hardened depth. This model considers the heat evacuated by the chips in a simplified way and takes into account the heat consumed by the fast austenitization process through an original methodology. Secondly, a model is proposed for the estimation of surface softening during finishing grinding. A methodology is presented for the prediction of surface hardness under non-isothermal tempering. Both models are calibrated and validated for the AISI 1045 steel, and the predicted results are in agreement with the experimental data for the studied grinding regimes. In this regard, the grind-hardening model predicts the hardness penetration depth (HPD) precisely for HPD values over 0.2 mm. The finishing model estimates the surface hardness after the finishing of the workpiece with an error lower than 6 %.
Advances in Non Conventional Materials Processing Technologies, 2012
Grinding is a stochastic process applied in the last stages of the manufacturing cycle. In last d... more Grinding is a stochastic process applied in the last stages of the manufacturing cycle. In last decades, grinding research has focused on prediction of thermal damage on ground workpiece since it is of considerable importance from both research and industrial perspectives. A number of numerical and analytical thermal models have been carried out so far. However, new grinding processes such as peel grinding, creep feed grinding and others such as plongee grinding need new models which consider the effect of higher depth of cuts, but there is no information about the minimum depth of cut to consider the elimination of grounded material in FEM models. This article establishes the frontier from which the removed ground material should be physically eliminated to obtain an accurate FEM thermal model. Results show valuable information to decide which kind of model (with or without element elimination) is enough accurate for their purpose and application.
The International Journal of Advanced Manufacturing Technology, 2013
Grind-hardening is an innovative manufacturing process that takes advantage of the high amount of... more Grind-hardening is an innovative manufacturing process that takes advantage of the high amount of heat generated in the contact zone to produce a martensitic phase transformation in the subsurface layer of the workpiece. However, for a successful industrial implementation of the process, the closed loop control of the hardening depth is essential. Firstly, in this paper, cylindrical traverse grinding tests and metallographic analysis are conducted, and a grinding parameter that enables the in-process control of the hardness penetration depth (HPD) is proposed. Secondly, a nondestructive method based on the Barkhausen noise technique is presented as a quality control procedure for the HPD estimation. Keywords Grind-hardening. Cylindrical traverse grinding. Surface integrity. Barkhausen noise Abbreviations BN Barkhausen noise HPD Hardness penetration depth RMS Root mean square Nomenclature a e Depth of cut (mm) a f Axial feed per revolution (mm/revolution) b seff Effective width of cut (mm) d e Equivalent diameter (mm) e c Specific grinding energy (J/mm 3) E c ″ Area-specific grinding energy (J/mm 2) f Frequency of the BN signal (Hz) F t Tangential force (N) l g Length of contact (mm) P c ″ Area-specific grinding power (W/mm 2) v c Cutting speed (m/s) v f Axial feed rate (mm/min) v s Grinding wheel speed (m/s) v w Workpiece peripheral speed (m/s) σ Electrical conductivity (Ω −1 m −1) μ Magnetic permeability (T m A −1
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