A fundamental understanding of ablation in different incidence angles is indispensable to expand the result to volume ablation where nonperpendicular irradiation exists. So far, no study with this orientation has been conducted in the category of volume laser machining. In this study, a nanosecond laser with different fluencies was utilized for single-point ablation experiments. The effect of incidence angles of 0°, 30°, and 60° on the ablation depth and the crater geometry was evaluated. Different laser pulse numbers are also considered. The results show that the ablation depth for 0° and 30° angles is almost in the same range for the initial pulses, but afterward, the ablation depth for the incidence 30° drops considerably. As the number of incident pulses increases, the ablation depth first develops approximately linearly and then grows exponentially. By changing the incident from 0° to 60°, the affecting area changes as well. The affecting area could be categorized into two distinct areas: (1) ablation area (A.A) where the crater ablation depth rapidly increases for the first 20 pulses and then, as more incident pulses arrive, it does not grow anymore and reaches a plateau due to the increase in the ablation depth. The second area (2) is the heat-affected area (H.A.A) of the crater where no further ablation occurs, but due to heat accumulation, it becomes constantly bigger when more incident pulses strike the crater. This heat-affected area tends to stay almost constant for the first incident pulses (up to 10) and, after a sharp increase, tends to enlarge steadily as the number of incident pulses rises to 70.
{"title":"Investigation of NS-single-point laser ablation of bronze under different incidence angles and pulses","authors":"Esmaeil Ghadiri Zahrani, Bahman Azarhoushang","doi":"10.2351/7.0001146","DOIUrl":"https://doi.org/10.2351/7.0001146","url":null,"abstract":"A fundamental understanding of ablation in different incidence angles is indispensable to expand the result to volume ablation where nonperpendicular irradiation exists. So far, no study with this orientation has been conducted in the category of volume laser machining. In this study, a nanosecond laser with different fluencies was utilized for single-point ablation experiments. The effect of incidence angles of 0°, 30°, and 60° on the ablation depth and the crater geometry was evaluated. Different laser pulse numbers are also considered. The results show that the ablation depth for 0° and 30° angles is almost in the same range for the initial pulses, but afterward, the ablation depth for the incidence 30° drops considerably. As the number of incident pulses increases, the ablation depth first develops approximately linearly and then grows exponentially. By changing the incident from 0° to 60°, the affecting area changes as well. The affecting area could be categorized into two distinct areas: (1) ablation area (A.A) where the crater ablation depth rapidly increases for the first 20 pulses and then, as more incident pulses arrive, it does not grow anymore and reaches a plateau due to the increase in the ablation depth. The second area (2) is the heat-affected area (H.A.A) of the crater where no further ablation occurs, but due to heat accumulation, it becomes constantly bigger when more incident pulses strike the crater. This heat-affected area tends to stay almost constant for the first incident pulses (up to 10) and, after a sharp increase, tends to enlarge steadily as the number of incident pulses rises to 70.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139303161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Kardan, N. Levichev, Sylvie Castagne, Joost R. Duflou
Cutting thick plates is affected not only by the laser power but also by the cut kerf width and the melt flow dynamics that determine the ejection of the molten material. Employing the same laser beam intensity distribution for various thicknesses is the limiting factor when cutting thicker plates. This paper investigates fiber laser fusion cutting of 25 mm thick aluminum with dynamic beam shaping (DBS). While both static and longitudinal dynamic intensity distributions fail to cut this thickness with a 4 kW laser power, a cut through is achieved using annular and elliptical intensity distributions. However, an improvement of 45% in cutting speed can be achieved using an elliptical intensity distribution compared to an annular one. In order to understand the effect of the beam shape, an infrared thermal camera is used to study lateral heat propagation when using different process parameters. Moreover, to analyze the melt flow when changing the DBS frequency, high-speed imaging is utilized to observe the molten material inside the cut kerf. Finally, the cut edge quality is investigated for different cutting conditions.
{"title":"Cutting thick aluminum plates using laser fusion cutting enhanced by dynamic beam shaping","authors":"M. Kardan, N. Levichev, Sylvie Castagne, Joost R. Duflou","doi":"10.2351/7.0001095","DOIUrl":"https://doi.org/10.2351/7.0001095","url":null,"abstract":"Cutting thick plates is affected not only by the laser power but also by the cut kerf width and the melt flow dynamics that determine the ejection of the molten material. Employing the same laser beam intensity distribution for various thicknesses is the limiting factor when cutting thicker plates. This paper investigates fiber laser fusion cutting of 25 mm thick aluminum with dynamic beam shaping (DBS). While both static and longitudinal dynamic intensity distributions fail to cut this thickness with a 4 kW laser power, a cut through is achieved using annular and elliptical intensity distributions. However, an improvement of 45% in cutting speed can be achieved using an elliptical intensity distribution compared to an annular one. In order to understand the effect of the beam shape, an infrared thermal camera is used to study lateral heat propagation when using different process parameters. Moreover, to analyze the melt flow when changing the DBS frequency, high-speed imaging is utilized to observe the molten material inside the cut kerf. Finally, the cut edge quality is investigated for different cutting conditions.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139304939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cemented carbide (WC-Co), the widely used tool-die material, is difficult to be machined by conventional and nonconventional techniques. This inspired exploring additive manufacturing (AM) of this material. However, porosity, brittleness due to cobalt depletion, etc. have been reported in the literature with rare success. For the AM of WC-Co, the current work focuses on directed energy deposition, which can be implemented with existing laser cutting-welding workstations, with modifications. To ensure the retention of cobalt even after inevitable vaporization of some of its initial content during deposition, 20 wt. % of Co was mixed with WC powder by low-energy ball milling. Laser power, scan speed, and powder flow rate were varied following a full-factorial design of experiments. The analysis of variance revealed that the experimental model and most of the parameters were significant. Only the laser power came out to be insignificant for the contact angle. The track height and width increased with the laser power and reduced with the scan speed. The contact angle increased with the scan speed and reduced with the powder flow rate. Cross sections of the deposited track showed no pores or cracks. Multiobjective optimization with gray relational analysis was conducted to get the parameter combination giving high values of the contact angle, track height, and width simultaneously. The optimum parameter combination, thus, obtained is 700 W laser power, 5 mm/s scan speed, and 5 g/min powder flow rate. This yielded 305 ± 40 μm track height, 2132 ± 33 μm width, and 152° ± 2° contact angle.
{"title":"Parametric investigation and optimization in laser based directed energy deposition of tungsten carbide-cobalt","authors":"Ankit Shrivastava, Anirban Changdar, Abhijit Datta, Samik Dutta, Shitanshu Shekhar Chakraborty","doi":"10.2351/7.0001179","DOIUrl":"https://doi.org/10.2351/7.0001179","url":null,"abstract":"Cemented carbide (WC-Co), the widely used tool-die material, is difficult to be machined by conventional and nonconventional techniques. This inspired exploring additive manufacturing (AM) of this material. However, porosity, brittleness due to cobalt depletion, etc. have been reported in the literature with rare success. For the AM of WC-Co, the current work focuses on directed energy deposition, which can be implemented with existing laser cutting-welding workstations, with modifications. To ensure the retention of cobalt even after inevitable vaporization of some of its initial content during deposition, 20 wt. % of Co was mixed with WC powder by low-energy ball milling. Laser power, scan speed, and powder flow rate were varied following a full-factorial design of experiments. The analysis of variance revealed that the experimental model and most of the parameters were significant. Only the laser power came out to be insignificant for the contact angle. The track height and width increased with the laser power and reduced with the scan speed. The contact angle increased with the scan speed and reduced with the powder flow rate. Cross sections of the deposited track showed no pores or cracks. Multiobjective optimization with gray relational analysis was conducted to get the parameter combination giving high values of the contact angle, track height, and width simultaneously. The optimum parameter combination, thus, obtained is 700 W laser power, 5 mm/s scan speed, and 5 g/min powder flow rate. This yielded 305 ± 40 μm track height, 2132 ± 33 μm width, and 152° ± 2° contact angle.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135410350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Timo Rautio, Matias Jaskari, Markku Keskitalo, Joonas Päkkilä, Antti Järvenpää
Additive manufacturing is an enticing way of producing complex geometries and optimized parts for special applications. Even though the achievable static properties for the printed material are usually good when compared to wrought materials, in many cases dynamic properties are known to be much worse. Often, the quality is sacrificed in respect of printing speed. Furthermore, printed materials have usually anisotropic behavior, caused by the remelting and fast cooling of each deposited layer. This means that the mechanical properties need to be measured in several directions in respect of the printing direction for attaining a more holistic approach to the achieved static and dynamic behavior. As a demonstration, this study focuses on determining the properties of 316L stainless steel-manufactured with laser powder bed fusion. A comprehensive set of samples for various testing methods were manufactured to investigate the effect of the layer thickness and printing orientation on the microstructure, mechanical properties, impact strength, and fatigue life. Fatigue performance of the material was evaluated in both axial and flexural bending comparing as-built and polished surface conditions. Bending fatigue testing revealed that a fatigue limit of 100 MPa at best can be achieved with the as-built surface quality, but with a polished surface and lower layer thickness, it could be doubled. Impact toughness and mechanical strength of the material are heavily dependent on the layer thickness, and while the best results were obtained with the lower layer thickness, the printing orientation can have a detrimental effect on it.
{"title":"Fatigue strength and impact toughness dependence of powder bed fusion with laser beam-manufactured 316L stainless steel on orientation and layer thickness","authors":"Timo Rautio, Matias Jaskari, Markku Keskitalo, Joonas Päkkilä, Antti Järvenpää","doi":"10.2351/7.0001113","DOIUrl":"https://doi.org/10.2351/7.0001113","url":null,"abstract":"Additive manufacturing is an enticing way of producing complex geometries and optimized parts for special applications. Even though the achievable static properties for the printed material are usually good when compared to wrought materials, in many cases dynamic properties are known to be much worse. Often, the quality is sacrificed in respect of printing speed. Furthermore, printed materials have usually anisotropic behavior, caused by the remelting and fast cooling of each deposited layer. This means that the mechanical properties need to be measured in several directions in respect of the printing direction for attaining a more holistic approach to the achieved static and dynamic behavior. As a demonstration, this study focuses on determining the properties of 316L stainless steel-manufactured with laser powder bed fusion. A comprehensive set of samples for various testing methods were manufactured to investigate the effect of the layer thickness and printing orientation on the microstructure, mechanical properties, impact strength, and fatigue life. Fatigue performance of the material was evaluated in both axial and flexural bending comparing as-built and polished surface conditions. Bending fatigue testing revealed that a fatigue limit of 100 MPa at best can be achieved with the as-built surface quality, but with a polished surface and lower layer thickness, it could be doubled. Impact toughness and mechanical strength of the material are heavily dependent on the layer thickness, and while the best results were obtained with the lower layer thickness, the printing orientation can have a detrimental effect on it.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135410357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Koti, John Powell, Himani Naesstroem, Chiara Spaccapaniccia, K. T. Voisey
This paper provides quantitative information about the paths taken by blown powder particles during laser cladding. A proportion of the powder is “wasted” by bouncing off the solid areas surrounding the melt pool. This wastage reduces the productivity and profitability of the process. In this paper, specially developed software was used to analyze high-speed imaging videos of the cladding process, to monitor the directions of powder particle flight toward and away from the melt pool area. This information has been correlated to the geometry and position of the melt pool zone for three different cladding techniques: single track cladding (A tracks), standard overlapping track cladding (AAA cladding), and a recently developed technique called ABA cladding. The results show that the melt pool geometry, and particularly the overlap between the melt pool and the incoming powder stream, has a strong influence on powder catchment efficiency. ABA cladding was found to have considerably better powder catchment efficiency than standard AAA cladding and this improvement can be explained by consideration of the geometries and positions of the melt pools and surrounding solid material in each case. As powder costs are an important factor in industrial laser cladding, the adaption of the ABA technique, and/or control of pool/powder stream overlap (e.g., by making the powder stream not coaxial with the laser beam), could improve the profitability of the process.
{"title":"Laser cladding: A high-speed-imaging examination of powder catchment efficiency as a function of the melt pool geometry and its position under the powder stream","authors":"Daniel Koti, John Powell, Himani Naesstroem, Chiara Spaccapaniccia, K. T. Voisey","doi":"10.2351/7.0001199","DOIUrl":"https://doi.org/10.2351/7.0001199","url":null,"abstract":"This paper provides quantitative information about the paths taken by blown powder particles during laser cladding. A proportion of the powder is “wasted” by bouncing off the solid areas surrounding the melt pool. This wastage reduces the productivity and profitability of the process. In this paper, specially developed software was used to analyze high-speed imaging videos of the cladding process, to monitor the directions of powder particle flight toward and away from the melt pool area. This information has been correlated to the geometry and position of the melt pool zone for three different cladding techniques: single track cladding (A tracks), standard overlapping track cladding (AAA cladding), and a recently developed technique called ABA cladding. The results show that the melt pool geometry, and particularly the overlap between the melt pool and the incoming powder stream, has a strong influence on powder catchment efficiency. ABA cladding was found to have considerably better powder catchment efficiency than standard AAA cladding and this improvement can be explained by consideration of the geometries and positions of the melt pools and surrounding solid material in each case. As powder costs are an important factor in industrial laser cladding, the adaption of the ABA technique, and/or control of pool/powder stream overlap (e.g., by making the powder stream not coaxial with the laser beam), could improve the profitability of the process.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135509884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. M. Sánchez-Amaya, A. Gómez-Parra, C. Churiaque, S. R. Fernández-Vidal, A. J. Gámez
In the present research, the hybrid laser arc welding (HLAW) process has been applied to join 8 mm thick structural S355J2N steel under 1G configuration. Welding tests were performed at the Laser Welding Advanced Center available at the University of Cadiz, Spain. Different experimental welding parameters were fitted to obtain sound butt welds. The welds were subjected to different quality control tests, including visual inspection, metallographic characterization, microhardness measurements, and tensile and fatigue tests. The HLAW tests were performed at higher welding rates in 1G configuration than previously reported for 8 mm thick steels. Complete penetration was achieved in all welds, presenting suitable geometries without defects such as cracks, root humps, or porosities. Microhardness values measured at different welding zones were always below 350 HV. All welds broke at the base metal in the tensile tests. The present contribution reports novel fatigue results for these butt hybrid welds. The samples welded at the highest welding rate (2.5 m/min) were the ones providing the best fatigue response, due to the lower heat input applied under this condition.
{"title":"Fatigue behavior of <scp>8 </scp>mm thick steel butt joints performed with hybrid laser arc welding","authors":"J. M. Sánchez-Amaya, A. Gómez-Parra, C. Churiaque, S. R. Fernández-Vidal, A. J. Gámez","doi":"10.2351/7.0001084","DOIUrl":"https://doi.org/10.2351/7.0001084","url":null,"abstract":"In the present research, the hybrid laser arc welding (HLAW) process has been applied to join 8 mm thick structural S355J2N steel under 1G configuration. Welding tests were performed at the Laser Welding Advanced Center available at the University of Cadiz, Spain. Different experimental welding parameters were fitted to obtain sound butt welds. The welds were subjected to different quality control tests, including visual inspection, metallographic characterization, microhardness measurements, and tensile and fatigue tests. The HLAW tests were performed at higher welding rates in 1G configuration than previously reported for 8 mm thick steels. Complete penetration was achieved in all welds, presenting suitable geometries without defects such as cracks, root humps, or porosities. Microhardness values measured at different welding zones were always below 350 HV. All welds broke at the base metal in the tensile tests. The present contribution reports novel fatigue results for these butt hybrid welds. The samples welded at the highest welding rate (2.5 m/min) were the ones providing the best fatigue response, due to the lower heat input applied under this condition.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135515073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Markus Wagner, Fabian Günther, Rishabh Rajesh Rao, Uwe Stamm, Dirk Dittrich, Axel Jahn
Laser welding in transmission manufacturing opens up completely new kinds of product solutions with excellent properties in terms of wear, corrosion resistance, and service life. Current welding designs are characterized in particular by difficult-to-weld material combinations (e.g., steel versus cast iron) and a high component stiffness, which is correlated with high residual welding stresses. The major challenge for these mass-produced components remains both their crack-free weldability and their complex cyclic load capacity [U. Stamm, “Rissfreies Laserstrahlschweißen von Mischverbindungen aus Gusseisen und Einsatzstahl, Jahresbericht Fraunhofer IWS 2006” (2006); X. Shu, “Untersuchungen zum Laserstrahlschweißen von Werkstoffkombinationen aus Gußeisen und Stahl,” Dissertation, Shaker, Band 4/94 (1994), ISBN: 3-8265-0098-9; G. Göbel, “Erweiterung der Prozessgrenzen beim Laserstrahlschweißen heißrissgefährdeter Werkstoffe,” Dissertation, Fraunhofer-IRB-Verlag (2007), ISBN: 978-3-8167-7671-0]. Therefore, this contribution presents practical solutions for weld-compatible joint constructions and the reduction of residual stresses on the basis of a representative transmission design. Specifically, a systematic study is being conducted to understand and qualitatively evaluate effective methods for reducing residual weld stresses in circumferential welds. The recommendations developed as part of this study take particular account of the influence of process modifications, material conditions, and geometric aspects on weldability and component distortion. Here, structural welding simulations are performed and verified by experimental welding trials, including metallographic examinations. To ensure the required component fatigue strength, a practical concept for determining Wöhler curves is presented, which is based on structural mechanical simulations and multiaxial fatigue strength tests on simplified test specimens. The adaptations developed in this way facilitate the production of difficult-to-weld and highly stressed transmission components. In particular, time-consuming and cost-intensive iterations of laser welding tests can be significantly reduced or even eliminated [Brenner et al., “Neuere Ergebnisse zum Schweißen von Eisenbasiswerkstoffen mit Faserlasern, 5. Laser-Anwenderforum,” Strahltechnik Band 28 (2006), pp. 139–148, ISBN: 3-933762-18-9, S]. Furthermore, the systematic investigations provide effective recommendations for phenomenological understanding and solving typical welding challenges in practice [J. Standfuß, “Ganzheitliche innovative fügetechnische Konzepte am Beispiel des PKW-Antriebsstranges,” Fraunhofer Verlag (2010), ISBN: 978-3-8396-0125-9]. This applies, in particular, to load-transmitting components in the fields of e-mobility, aerospace, and industrial engineering [Wagner et al., “Entwickeln und Auslegen von lasergeschweißten Getriebe-komponenten für die Luftfahrt,” DVS-Berichte Band 365 (2020), pp. 62–69, ISBN: 978-3-96144
激光焊接在传动制造中开辟了全新的产品解决方案，在耐磨、耐腐蚀和使用寿命方面具有优异的性能。当前的焊接设计尤其以难以焊接的材料组合(例如，钢与铸铁)和高部件刚度为特征，这与高残余焊接应力相关。这些量产部件面临的主要挑战是其无裂纹焊接性和复杂的循环载荷能力。斯塔姆，“激光辐射与激光辐射”，德国劳恩霍夫学会(2006);舒欣，“Untersuchungen zum Laserstrahlschweißen von Werkstoffkombinationen aus Gußeisen und Stahl”，博士论文，振动，第4/94期(1994)，ISBN: 3-8265-0098-9;G. Göbel，“Erweiterung der Prozessgrenzen beim Laserstrahlschweißen heißrissgefährdeter Werkstoffe”，Dissertation, Fraunhofer-IRB-Verlag (2007)， ISBN: 978-3-8167-7671-0]。因此，这一贡献为焊接兼容接头结构和减少残余应力提供了实用的解决方案，并以代表性传动设计为基础。具体来说，正在进行一项系统的研究，以了解和定性评估减少环向焊缝残余应力的有效方法。作为本研究的一部分，提出的建议特别考虑了工艺修改、材料条件和几何方面对可焊性和部件变形的影响。在这里，进行了结构焊接模拟，并通过实验焊接试验进行了验证，包括金相检查。为了保证构件所需的疲劳强度，提出了一种基于结构力学模拟和简化试件多轴疲劳强度试验的Wöhler曲线确定的实用概念。以这种方式开发的适应性有助于生产难以焊接和高应力的传动部件。特别是，激光焊接测试的耗时和成本密集的迭代可以大大减少甚至消除[Brenner等人，“Neuere Ergebnisse zum schweien von Eisenbasiswerkstoffen mit faserlasen, 5]。Laser-Anwenderforum， " Strahltechnik Band 28 (2006)， pp. 139-148, ISBN: 3-933762-18-9, S]。此外，系统的研究为理解现象学和解决实践中的典型焊接挑战提供了有效的建议[J]。斯坦弗斯，“Ganzheitliche innovative f getechnische Konzepte am Beispiel des PKW-Antriebsstranges”，弗劳恩霍夫出版社(2010)，ISBN: 978-3-8396-0125-9。这尤其适用于电动汽车、航空航天和工业工程领域的负载传输组件[Wagner等人，“Entwickeln und Auslegen von lasergeschweißten Getriebe-komponenten f r die Luftfahrt，”DVS-Berichte Band 365 (2020)， pp. 62-69, ISBN: 978-3-96144-098-6]。
{"title":"New possibilities for laser welding of highly loaded transmission components by strategic use of simulation methods","authors":"Markus Wagner, Fabian Günther, Rishabh Rajesh Rao, Uwe Stamm, Dirk Dittrich, Axel Jahn","doi":"10.2351/7.0001189","DOIUrl":"https://doi.org/10.2351/7.0001189","url":null,"abstract":"Laser welding in transmission manufacturing opens up completely new kinds of product solutions with excellent properties in terms of wear, corrosion resistance, and service life. Current welding designs are characterized in particular by difficult-to-weld material combinations (e.g., steel versus cast iron) and a high component stiffness, which is correlated with high residual welding stresses. The major challenge for these mass-produced components remains both their crack-free weldability and their complex cyclic load capacity [U. Stamm, “Rissfreies Laserstrahlschweißen von Mischverbindungen aus Gusseisen und Einsatzstahl, Jahresbericht Fraunhofer IWS 2006” (2006); X. Shu, “Untersuchungen zum Laserstrahlschweißen von Werkstoffkombinationen aus Gußeisen und Stahl,” Dissertation, Shaker, Band 4/94 (1994), ISBN: 3-8265-0098-9; G. Göbel, “Erweiterung der Prozessgrenzen beim Laserstrahlschweißen heißrissgefährdeter Werkstoffe,” Dissertation, Fraunhofer-IRB-Verlag (2007), ISBN: 978-3-8167-7671-0]. Therefore, this contribution presents practical solutions for weld-compatible joint constructions and the reduction of residual stresses on the basis of a representative transmission design. Specifically, a systematic study is being conducted to understand and qualitatively evaluate effective methods for reducing residual weld stresses in circumferential welds. The recommendations developed as part of this study take particular account of the influence of process modifications, material conditions, and geometric aspects on weldability and component distortion. Here, structural welding simulations are performed and verified by experimental welding trials, including metallographic examinations. To ensure the required component fatigue strength, a practical concept for determining Wöhler curves is presented, which is based on structural mechanical simulations and multiaxial fatigue strength tests on simplified test specimens. The adaptations developed in this way facilitate the production of difficult-to-weld and highly stressed transmission components. In particular, time-consuming and cost-intensive iterations of laser welding tests can be significantly reduced or even eliminated [Brenner et al., “Neuere Ergebnisse zum Schweißen von Eisenbasiswerkstoffen mit Faserlasern, 5. Laser-Anwenderforum,” Strahltechnik Band 28 (2006), pp. 139–148, ISBN: 3-933762-18-9, S]. Furthermore, the systematic investigations provide effective recommendations for phenomenological understanding and solving typical welding challenges in practice [J. Standfuß, “Ganzheitliche innovative fügetechnische Konzepte am Beispiel des PKW-Antriebsstranges,” Fraunhofer Verlag (2010), ISBN: 978-3-8396-0125-9]. This applies, in particular, to load-transmitting components in the fields of e-mobility, aerospace, and industrial engineering [Wagner et al., “Entwickeln und Auslegen von lasergeschweißten Getriebe-komponenten für die Luftfahrt,” DVS-Berichte Band 365 (2020), pp. 62–69, ISBN: 978-3-96144","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135614680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Franz, Yongting Yang, Luis Michel, Cemal Esen, Ralf Hellmann
We report for the first time on the realization, characterization and application of an ultrashort pulsed laser robot system for flexible and large-area 2D and 3D laser micromachining with 6 articulated axes. To characterize the dynamic positioning of the laser beam during and after axes movement, CMOS image sensors were integrated into the beam path. A method introduced for the alignment of the optical axes allows a reduction of the deviations in laser beam positioning to less than 141.8 ± 92.9 μm within a 110° rotation range of axis 4. In addition, a high laser beam positioning repeatability of less than 102.2 μm is demonstrated over a total period of 14 h for a movement of axis 5 within a range of 0° to 90°. Initial laser cutting, laser structuring and laser marking applications on automotive dashboards and glass substrates are presented for flexible and large area 2D and 3D manufacturing. By applying a special laser cutting strategy for processing AF 32 eco thin glass, high cutting quality is achieved with a taper of up to 96.3% without the generation of cracks, demonstrating the innovative potential of the high-precision laser robot system. Nonetheless, different identified inherent influences of each axis 1–5 during robot axis movement demand for an innovative beam stabilization concept to achieve high precision in laser beam positioning.
{"title":"Evaluation of an ultrashort pulsed laser robot system for flexible and large-area micromachining","authors":"Daniel Franz, Yongting Yang, Luis Michel, Cemal Esen, Ralf Hellmann","doi":"10.2351/7.0001171","DOIUrl":"https://doi.org/10.2351/7.0001171","url":null,"abstract":"We report for the first time on the realization, characterization and application of an ultrashort pulsed laser robot system for flexible and large-area 2D and 3D laser micromachining with 6 articulated axes. To characterize the dynamic positioning of the laser beam during and after axes movement, CMOS image sensors were integrated into the beam path. A method introduced for the alignment of the optical axes allows a reduction of the deviations in laser beam positioning to less than 141.8 ± 92.9 μm within a 110° rotation range of axis 4. In addition, a high laser beam positioning repeatability of less than 102.2 μm is demonstrated over a total period of 14 h for a movement of axis 5 within a range of 0° to 90°. Initial laser cutting, laser structuring and laser marking applications on automotive dashboards and glass substrates are presented for flexible and large area 2D and 3D manufacturing. By applying a special laser cutting strategy for processing AF 32 eco thin glass, high cutting quality is achieved with a taper of up to 96.3% without the generation of cracks, demonstrating the innovative potential of the high-precision laser robot system. Nonetheless, different identified inherent influences of each axis 1–5 during robot axis movement demand for an innovative beam stabilization concept to achieve high precision in laser beam positioning.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136023536","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jurandir Marcos Sá de Sousa, Milton Pereira, Juliane Ribeiro da Cruz, Anselmo Thiesen Júnior, Henrique Santos Ferreira, Jhonattan Gutjahr
Additively manufactured martensitic stainless steel components can combine complex geometry with superior mechanical and corrosion performance. In this work, the mechanical performance of AISI 410L processed by laser directed energy deposition (L-DED) additive manufacturing using previously optimized parameters is assessed. Microstructure, hardness, tensile strength, and Charpy impact toughness are evaluated in the as-built and heat-treated conditions. Four heat-treatment routes are investigated: (I) austenitization and water quenched, and austenitization, water quenched, and tempered at (II) 300, (III) 450, and (IV) 600 °C, followed by air cooling. The results show that, for tempering temperatures up to 450 °C, the hardness, yield strength, and ultimate tensile strength show an increasing trend when compared with the as-built condition and reference commercial standard (annealed AISI 410) because of microstructure refinement induced by recrystallization. Tempering at 600 °C, on the other hand, enhances the ductility of the specimens, accounting for an increased deformation until fracture and superior Charpy impact toughness. In summary, this work demonstrates that, for all tested conditions, the tensile strength of the AISI 410L additively manufactured by L-DED outperforms that of the standardized commercial AISI 410 martensitic stainless steel, and that post-processing heat-treatments can be used to further enhance toughness and ductility, making it even more competitive.
{"title":"Influence of post-processing heat-treatment on the mechanical performance of AISI 410L stainless steel manufactured by the L-DED process","authors":"Jurandir Marcos Sá de Sousa, Milton Pereira, Juliane Ribeiro da Cruz, Anselmo Thiesen Júnior, Henrique Santos Ferreira, Jhonattan Gutjahr","doi":"10.2351/7.0001135","DOIUrl":"https://doi.org/10.2351/7.0001135","url":null,"abstract":"Additively manufactured martensitic stainless steel components can combine complex geometry with superior mechanical and corrosion performance. In this work, the mechanical performance of AISI 410L processed by laser directed energy deposition (L-DED) additive manufacturing using previously optimized parameters is assessed. Microstructure, hardness, tensile strength, and Charpy impact toughness are evaluated in the as-built and heat-treated conditions. Four heat-treatment routes are investigated: (I) austenitization and water quenched, and austenitization, water quenched, and tempered at (II) 300, (III) 450, and (IV) 600 °C, followed by air cooling. The results show that, for tempering temperatures up to 450 °C, the hardness, yield strength, and ultimate tensile strength show an increasing trend when compared with the as-built condition and reference commercial standard (annealed AISI 410) because of microstructure refinement induced by recrystallization. Tempering at 600 °C, on the other hand, enhances the ductility of the specimens, accounting for an increased deformation until fracture and superior Charpy impact toughness. In summary, this work demonstrates that, for all tested conditions, the tensile strength of the AISI 410L additively manufactured by L-DED outperforms that of the standardized commercial AISI 410 martensitic stainless steel, and that post-processing heat-treatments can be used to further enhance toughness and ductility, making it even more competitive.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136067819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Khalaf Ajaj, Mushtaq Abed Al-Jubbori, Abdullah M. Ali
In this study, we synthesized colloidal copper nanoparticles (CuNPs) utilizing Q-switched Nd:YAG laser ablation on a copper plate immersed in double-distilled water at energies of 200 and 400 mJ, respectively, with 100, 200, 300, 400, and 500 pulses. The size and optical properties of nanoparticles were determined using a UV–Vis spectrophotometer, a transmission electron microscope (TEM), and a field emission scanning electron microscope (FE-SEM). The absorption spectra exhibited two surface plasmon resonance peaks (λSPR), one at 217 nm for copper oxide nanoparticles (CuONPs) and the other at 636 nm for CuNPs, with the increase in laser pulses. Consequently, the optical bandgap increased by roughly 3 eV. The TEM and FE-SEM analyses showed nearly spherical Cu nanoparticles with average diameters of 33 and 38 nm for laser energies of 200 and 400 mJ, respectively. An analysis of x-ray diffraction patterns revealed that CuONPs contained the crystallographic planes of a monoclinic and an orthorhombic crystal system. Additionally, the mean crystallite size of laser-ablated nanoparticles increased with increasing pulse energy. Furthermore, the absorption and optical bandgap of CuNPs increased slightly with an increase in ultraviolet irradiation exposure. The results of our study showed an increased inhibitory effect against both Staphylococcus aureus bacteria and Escherichia coli bacteria when CuNPs were irradiated by ultraviolet type C.
{"title":"Influence of ultraviolet irradiation on the optical properties and biological activity of copper nanoparticles prepared by pulsed laser ablation","authors":"Khalaf Ajaj, Mushtaq Abed Al-Jubbori, Abdullah M. Ali","doi":"10.2351/7.0001221","DOIUrl":"https://doi.org/10.2351/7.0001221","url":null,"abstract":"In this study, we synthesized colloidal copper nanoparticles (CuNPs) utilizing Q-switched Nd:YAG laser ablation on a copper plate immersed in double-distilled water at energies of 200 and 400 mJ, respectively, with 100, 200, 300, 400, and 500 pulses. The size and optical properties of nanoparticles were determined using a UV–Vis spectrophotometer, a transmission electron microscope (TEM), and a field emission scanning electron microscope (FE-SEM). The absorption spectra exhibited two surface plasmon resonance peaks (λSPR), one at 217 nm for copper oxide nanoparticles (CuONPs) and the other at 636 nm for CuNPs, with the increase in laser pulses. Consequently, the optical bandgap increased by roughly 3 eV. The TEM and FE-SEM analyses showed nearly spherical Cu nanoparticles with average diameters of 33 and 38 nm for laser energies of 200 and 400 mJ, respectively. An analysis of x-ray diffraction patterns revealed that CuONPs contained the crystallographic planes of a monoclinic and an orthorhombic crystal system. Additionally, the mean crystallite size of laser-ablated nanoparticles increased with increasing pulse energy. Furthermore, the absorption and optical bandgap of CuNPs increased slightly with an increase in ultraviolet irradiation exposure. The results of our study showed an increased inhibitory effect against both Staphylococcus aureus bacteria and Escherichia coli bacteria when CuNPs were irradiated by ultraviolet type C.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136381576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：