The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Vinod Yadava - One of the best experts on this subject based on the ideXlab platform.
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Experimental analysis of Nd-YAG Laser Cutting of sheet materials – A review
Optics & Laser Technology, 2018Co-Authors: Amit Sharma, Vinod YadavaAbstract:Abstract Cutting of sheet material is considered as an important process due to its relevance among products of everyday life such as aircrafts, ships, cars, furniture etc. Among various sheet Cutting processes (ASCPs), Laser Beam Cutting is one of the most capable ASCP to create complex geometries with stringent design requirements in difficult-to-cut sheet materials. Based on the recent research work in the area of sheet Cutting, it is found that the Nd-YAG Laser is used for Cutting of sheet material in general and reflective sheet material in particular. This paper reviews the experimental analysis of Nd-YAG Laser Cutting process, carried out to study the influence of Laser Cutting parameters on the process performance index. The significance of experimental modeling and different optimization approaches employed by various researchers has also been discussed in this study.
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Intelligent Modelling and Multi-Objective Optimisation of Laser Beam Cutting of Nickel Based Superalloy Sheet
International Journal of Manufacturing Materials and Mechanical Engineering, 2013Co-Authors: Amit Sharma, Vinod Yadava, K. B. JudalAbstract:In the present study, a novel technique, namely, evolutionary non-dominated sorting genetic algorithm-II (NSGA-II) was used in conjunction with developed artificial neural network (ANN) model to select optimal process parameters for achieving the better process performance in LBC. First, ANN with backpropagation algorithm was used to model the LBC of nickel based superalloy sheets. The input process parameters taken were oxygen pressure, pulse width, pulse frequency and Cutting speed. The performance characteristics of interest in nickel based superalloy thin sheet Cutting are average kerf taper and surface roughness. The ANN model was trained and tested using the experimental data obtained through experimentation on pulsed Nd-YAG Laser Beam machining system. The 4-10-11-2 backpropagation architecture was found more accurate and generalized for given problem with good prediction capability. The results show that the developed modelling and optimization tool is effective for process parameter optimization in LBC process. The optimization of the process suggests that for achieving high cut quality characteristics the pulse width, pulse frequency and Cutting speed are set to lower limit within the available range and gas pressure is set to a level which is sufficient to remove the molten metal from the kerf.
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Modelling and optimization of cut quality during pulsed Nd:YAG Laser Cutting of thin Al-alloy sheet for straight profile
Optics & Laser Technology, 2012Co-Authors: Amit Sharma, Vinod YadavaAbstract:Abstract Thin sheets of aluminium alloys are widely used in aerospace and automotive industries for specific applications. Nd:YAG Laser Beam Cutting is one of the most promising sheetmetal Cutting process for Cutting sheets for any profile. Al-alloy sheets are difficult to cut by Laser Beam because of its highly reflective nature. This paper presents modelling and optimization of cut quality during pulsed Nd:YAG Laser Cutting of thin Al-alloy sheet for straight profile. In the present study, four input process parameters such as oxygen pressure, pulse width, pulse frequency, and Cutting speed and two output parameters such as average kerf taper (Ta) and average surface roughness (Ra) are considered. The hybrid approach comprising of Taguchi methodology (TM) and response surface methodology (RSM) is used for modelling whereas multi-objective optimization is performed using hybrid approach of TM and grey relational analysis (GRA) coupled with entropy measurement methodology. The entropy measurement methodology is employed for the calculation of weight corresponding to each quality characteristic. The results indicate that the hybrid approaches applied for modelling and optimization of the LBC process are reasonable.
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Robust parameter design and multi-objective optimization of Laser Beam Cutting for aluminium alloy sheet
The International Journal of Advanced Manufacturing Technology, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:The application of Laser Beam for precise Cutting of sheet metals, in general, and reflective sheet metals, like aluminium, in particular, has become of interest in the recent past. The optimum choice of the Cutting parameters is essential for the economic and efficient Cutting of difficult to cut materials with Laser Beams. In this paper, a robust design and quality optimization tool called the Taguchi methodology has been applied to find the optimal Cutting parameters for Cutting of a reflective sheet made of aluminium alloy with a Nd:YAG Laser Beam. All the steps of the Taguchi method, such as a selection of orthogonal array, computation of signal-to-noise ratio, decision of optimum setting of parameters, and the analysis of variance (ANOVA), have been done by a self-developed software called computer aided robust parameter design ( CARPD ). A considerable improvement in the kerf taper (KT) and material removal rate (MRR) has been found by using Taguchi method-based predicted results. Confirmatory experimental results have shown good agreement with predicted results. Further, the Taguchi quality loss function has also been used for multi-objective optimization of Laser Beam Cutting of Al-alloy sheet. The results of multi-objective optimization are compared with the single-objective optimization and it has been found that the kerf taper was increased by 1.60% in multi-objective optimization while the MRR was same in both cases.
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Laser Beam machining—A review
International Journal of Machine Tools & Manufacture, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:Abstract Laser Beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. Laser Beam is focussed for melting and vaporizing the unwanted material from the parent material. It is suitable for geometrically complex profile Cutting and making miniature holes in sheetmetal. Among various type of Lasers used for machining in industries, CO2 and Nd:YAG Lasers are most established. In recent years, researchers have explored a number of ways to improve the LBM process performance by analysing the different factors that affect the quality characteristics. The experimental and theoretical studies show that process performance can be improved considerably by proper selection of Laser parameters, material parameters and operating parameters. This paper reviews the research work carried out so far in the area of LBM of different materials and shapes. It reports about the experimental and theoretical studies of LBM to improve the process performance. Several modelling and optimization techniques for the determination of optimum Laser Beam Cutting condition have been critically examined. The last part of this paper discusses the LBM developments and outlines the trend for future research.
Martina Zimmermann - One of the best experts on this subject based on the ideXlab platform.
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Mechanical Properties of Remote-Laser Cut CFRP and Thermographic Laser-Process Monitoring
Materials Sciences and Applications, 2020Co-Authors: Michael Rose, Sebastian Schettler, Florian Klemm, Eckhard Beyer, Martina ZimmermannAbstract:Remote-Laser Beam Cutting is a productive technology without tool wear. Especially when Cutting carbon fiber reinforced polymers (CFRP), it offers constant manufacturing quality. Since it is a thermal process, a heat-affected zone (HAZ) is formed at the edge of the cut. Based on quasi-static and cyclic mechanical tests on open-hole specimens, the influence of the process on the mechanical properties of CFRP is shown. The quasi-static tests are in good correlation with results from other researchers by indicating an increase in the maximum tensile stress of the test specimens, cut by remote-Laser. The reason is the rearrangement of the shear stresses and a reduction of the notch stress concentration. However, the results of the present study show that excessive expansion of the HAZ leads to a reduction in the maximum tensile stress compared to milled test specimens. Under cyclic load conditions, remote-Laser Beam Cutting does not lead to a more pronounced degradation than milling. The mechanical properties of the notched test pieces are sensitive to the expansion of the HAZ. For the production of components it is therefore necessary that the remote-Laser Beam Cutting is carried out under controlled and documentable conditions. For this purpose, process thermography was tested as a tool for quality assurance. The results show that the technology is basically suitable for this task.
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Influence of surface condition due to Laser Beam Cutting on the fatigue behavior of metastable austenitic stainless steel AISI 304
Engineering Fracture Mechanics, 2017Co-Authors: D.f. Pessoa, Patrick Herwig, Andreas Wetzig, Martina ZimmermannAbstract:Austenitic steels are among the stainless steels the most common used type of material to produce sheet metal parts which can be manufactured by Laser Beam Cutting in a useful manner. However, the use of this technique to manufacture structural thick parts is restricted due to the creation of macroscopic defects and the lack of reliable fatigue strength data. In this context, the fatigue behavior of sheet-like samples made of metastable austenitic stainless steel AISI 304 cut by Laser Beam is discussed in this paper. The analyses showed that Laser Beam Cutting creates three kinds of macroscopic defects, which are a pronounced relief-like structure along the cut surface, burr in the underside of the cut edge and pores in the interface between the recast layer and base material or inside the recast layer. As a consequence, the fatigue strength of parts cut by Laser Beam is 40% lower in comparison to specimens in a macroscopically quasi defect-free state. An evaluation of the fatigue results based on comprehensive fractographic analyses allows to explain the reasons for distinct differences between the aforementioned influence factors. The most significant reduction of fatigue life is attributed to the notch effect of the burr, followed by the notch effect created by pores, while the influence of the surface relief is of minor significance
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Influence of loading frequency and role of surface micro-defects on fatigue behavior of metastable austenitic stainless steel AISI 304
International Journal of Fatigue, 2017Co-Authors: D.f. Pessoa, G. Kirchhoff, Martina ZimmermannAbstract:Abstract High frequency fatigue testing always provokes questions about whether the testing conditions are representative for the real application conditions. Therefore, any influences coming from the testing procedure must be known and understood before relying on the fatigue data based on high frequency testing for component design and validation phases. For this reason and because metastable austenitic steels are well known for their strain rate sensitivity (Muller-Bollenhagen, 2011; Sorich, 2016), the steel AISI 304 and the role of surface micro-defects produced by Laser Beam Cutting were analyzed regarding the influence of load frequency on the cyclic response and fatigue behavior, and the findings of the investigation are thoroughly discussed in this paper. Fatigue tests were performed at load frequencies of 100 Hz and 1000 Hz using two resonance pulsation test systems, as well as by means of a servo-hydraulic test machine at 1 Hz and 50 Hz. All fatigue experiments were performed at tensile-tensile loading condition (R = 0.1). The cyclic deformation behavior was characterized based on the evaluation of stress-strain hysteresis loops and temperature measurements. The deformation-induced phase transformation from γ-austenite to α′-martensite was globally and locally evaluated by means of magneto-inductive measurements and EBSD analysis, respectively. Furthermore, for the first time it was possible to compare test results generated by a 1000 Hz resonance pulsation test system with results from a conventional resonance test stand cycling at around 100 Hz. The analyses showed that higher amounts of α′-martensite and lower plastic strain amplitudes are observed when the cyclic experiments are carried out at lower frequency, promoting higher fatigue strengths. Nevertheless, the influence of test frequency for specimens containing surface micro-defects is dominant in the low cycle fatigue (LCF) regime while in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) range the fatigue life determining parameter is the severity of the micro-notches present along the Laser cut surface.
Avanish Kumar Dubey - One of the best experts on this subject based on the ideXlab platform.
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Neuro Fuzzy Modeling of Laser Beam Cutting Process
Applied Mechanics and Materials, 2011Co-Authors: Arun Kumar Pandey, Avanish Kumar DubeyAbstract:Laser Beam Cutting (LBC) being a complex Cutting process needs a reliable model for prediction of the process performance. This research work presents a modeling study of LBC process. A hybrid approach of Artificial Neural Network (ANN) and Fuzzy Logic (FL) has been used for developing the Kerf width model. The developed Neuro Fuzzy model of Kerf width has also been compared with Response Surface Methodology (RSM) based model and it has been found that the values of Kerf width predicted by the Neuro Fuzzy Model are more closer to the experimental values.
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Robust parameter design and multi-objective optimization of Laser Beam Cutting for aluminium alloy sheet
The International Journal of Advanced Manufacturing Technology, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:The application of Laser Beam for precise Cutting of sheet metals, in general, and reflective sheet metals, like aluminium, in particular, has become of interest in the recent past. The optimum choice of the Cutting parameters is essential for the economic and efficient Cutting of difficult to cut materials with Laser Beams. In this paper, a robust design and quality optimization tool called the Taguchi methodology has been applied to find the optimal Cutting parameters for Cutting of a reflective sheet made of aluminium alloy with a Nd:YAG Laser Beam. All the steps of the Taguchi method, such as a selection of orthogonal array, computation of signal-to-noise ratio, decision of optimum setting of parameters, and the analysis of variance (ANOVA), have been done by a self-developed software called computer aided robust parameter design ( CARPD ). A considerable improvement in the kerf taper (KT) and material removal rate (MRR) has been found by using Taguchi method-based predicted results. Confirmatory experimental results have shown good agreement with predicted results. Further, the Taguchi quality loss function has also been used for multi-objective optimization of Laser Beam Cutting of Al-alloy sheet. The results of multi-objective optimization are compared with the single-objective optimization and it has been found that the kerf taper was increased by 1.60% in multi-objective optimization while the MRR was same in both cases.
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Laser Beam machining—A review
International Journal of Machine Tools & Manufacture, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:Abstract Laser Beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. Laser Beam is focussed for melting and vaporizing the unwanted material from the parent material. It is suitable for geometrically complex profile Cutting and making miniature holes in sheetmetal. Among various type of Lasers used for machining in industries, CO2 and Nd:YAG Lasers are most established. In recent years, researchers have explored a number of ways to improve the LBM process performance by analysing the different factors that affect the quality characteristics. The experimental and theoretical studies show that process performance can be improved considerably by proper selection of Laser parameters, material parameters and operating parameters. This paper reviews the research work carried out so far in the area of LBM of different materials and shapes. It reports about the experimental and theoretical studies of LBM to improve the process performance. Several modelling and optimization techniques for the determination of optimum Laser Beam Cutting condition have been critically examined. The last part of this paper discusses the LBM developments and outlines the trend for future research.
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Laser Beam machining a review
International Journal of Machine Tools & Manufacture, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:Abstract Laser Beam machining (LBM) is one of the most widely used thermal energy based non-contact type advance machining process which can be applied for almost whole range of materials. Laser Beam is focussed for melting and vaporizing the unwanted material from the parent material. It is suitable for geometrically complex profile Cutting and making miniature holes in sheetmetal. Among various type of Lasers used for machining in industries, CO2 and Nd:YAG Lasers are most established. In recent years, researchers have explored a number of ways to improve the LBM process performance by analysing the different factors that affect the quality characteristics. The experimental and theoretical studies show that process performance can be improved considerably by proper selection of Laser parameters, material parameters and operating parameters. This paper reviews the research work carried out so far in the area of LBM of different materials and shapes. It reports about the experimental and theoretical studies of LBM to improve the process performance. Several modelling and optimization techniques for the determination of optimum Laser Beam Cutting condition have been critically examined. The last part of this paper discusses the LBM developments and outlines the trend for future research.
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Multi-objective optimization of Nd:YAG Laser Cutting of nickel-based superalloy sheet using orthogonal array with principal component analysis
Optics and Lasers in Engineering, 2008Co-Authors: Avanish Kumar Dubey, Vinod YadavaAbstract:Laser Cutting of nickel-based superalloy sheets, having wide applications in aircraft and rocket industries, is important from the quality of cut point of view. Keeping this in view, a hybrid approach of Taguchi method (TM) and principal component analysis (PCA) has been applied for multi-objective optimization (MOO) of pulsed Nd:YAG Laser Beam Cutting (LBC) of nickel-based superalloy (SUPERNI 718) sheet to achieve better cut qualities within existing resources. The three-quality characteristics kerf width, kerf deviation (along the length of cut), and kerf taper have been considered for simultaneous optimization. The input parameters considered are assist gas pressure, pulse width, pulse frequency, and Cutting speed. Initially, single-objective optimization has been performed using TM and then the signal-to-noise (S/N) ratios obtained from TM have been further used in PCA for multi-objective optimization. The results of MOO include the prediction of optimum input parameter level and their relative significance on multiple quality characteristics (MQC). The responses at predicted optimum parameter level are in good agreement with the results of confirmation experiments conducted for verification tests.
D.f. Pessoa - One of the best experts on this subject based on the ideXlab platform.
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Influence of surface condition due to Laser Beam Cutting on the fatigue behavior of metastable austenitic stainless steel AISI 304
Engineering Fracture Mechanics, 2017Co-Authors: D.f. Pessoa, Patrick Herwig, Andreas Wetzig, Martina ZimmermannAbstract:Austenitic steels are among the stainless steels the most common used type of material to produce sheet metal parts which can be manufactured by Laser Beam Cutting in a useful manner. However, the use of this technique to manufacture structural thick parts is restricted due to the creation of macroscopic defects and the lack of reliable fatigue strength data. In this context, the fatigue behavior of sheet-like samples made of metastable austenitic stainless steel AISI 304 cut by Laser Beam is discussed in this paper. The analyses showed that Laser Beam Cutting creates three kinds of macroscopic defects, which are a pronounced relief-like structure along the cut surface, burr in the underside of the cut edge and pores in the interface between the recast layer and base material or inside the recast layer. As a consequence, the fatigue strength of parts cut by Laser Beam is 40% lower in comparison to specimens in a macroscopically quasi defect-free state. An evaluation of the fatigue results based on comprehensive fractographic analyses allows to explain the reasons for distinct differences between the aforementioned influence factors. The most significant reduction of fatigue life is attributed to the notch effect of the burr, followed by the notch effect created by pores, while the influence of the surface relief is of minor significance
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Influence of loading frequency and role of surface micro-defects on fatigue behavior of metastable austenitic stainless steel AISI 304
International Journal of Fatigue, 2017Co-Authors: D.f. Pessoa, G. Kirchhoff, Martina ZimmermannAbstract:Abstract High frequency fatigue testing always provokes questions about whether the testing conditions are representative for the real application conditions. Therefore, any influences coming from the testing procedure must be known and understood before relying on the fatigue data based on high frequency testing for component design and validation phases. For this reason and because metastable austenitic steels are well known for their strain rate sensitivity (Muller-Bollenhagen, 2011; Sorich, 2016), the steel AISI 304 and the role of surface micro-defects produced by Laser Beam Cutting were analyzed regarding the influence of load frequency on the cyclic response and fatigue behavior, and the findings of the investigation are thoroughly discussed in this paper. Fatigue tests were performed at load frequencies of 100 Hz and 1000 Hz using two resonance pulsation test systems, as well as by means of a servo-hydraulic test machine at 1 Hz and 50 Hz. All fatigue experiments were performed at tensile-tensile loading condition (R = 0.1). The cyclic deformation behavior was characterized based on the evaluation of stress-strain hysteresis loops and temperature measurements. The deformation-induced phase transformation from γ-austenite to α′-martensite was globally and locally evaluated by means of magneto-inductive measurements and EBSD analysis, respectively. Furthermore, for the first time it was possible to compare test results generated by a 1000 Hz resonance pulsation test system with results from a conventional resonance test stand cycling at around 100 Hz. The analyses showed that higher amounts of α′-martensite and lower plastic strain amplitudes are observed when the cyclic experiments are carried out at lower frequency, promoting higher fatigue strengths. Nevertheless, the influence of test frequency for specimens containing surface micro-defects is dominant in the low cycle fatigue (LCF) regime while in the high cycle fatigue (HCF) and very high cycle fatigue (VHCF) range the fatigue life determining parameter is the severity of the micro-notches present along the Laser cut surface.
Gunther Reinhart - One of the best experts on this subject based on the ideXlab platform.
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An automated path planning system for a robot with a Laser scanner for remote Laser Cutting and welding
2012 IEEE International Conference on Mechatronics and Automation, 2012Co-Authors: Jens Hatwig, Michael F. Zaeh, Pascal Minnerup, Gunther ReinhartAbstract:Remote Laser Beam welding (RLW) and remote Laser Beam Cutting (RLC) are technologies that are well suited for automated applications in industrial facilities due to their contactless mode of action. The main advantages of both processes are the high operation speed, good process quality and a tailored contour of the welding seams and Cutting kerfs. For an optimal use of these processes the Laser Beam has to be guided accurately over the work piece. A common technical realization of such processes is the combination of a Laser Beam deflection unit, a Laser scanner and an industrial robot. This setup represents a programming challenge, as the six degrees of freedom of the robot plus the two degrees of freedom of the Laser scanner lead to a kinematic redundant system. However, the advantages of this combination, the large robot workspace and the fast and precise motion of the Laser scanner make it a very attractive technology for improvement of welding and Cutting processes. An automated programming system for the described setup is presented in this paper.
