Santiago Caraguay, Thiago Soares Pereira, Francisco Ratuznei, Miriam Zareth Parra Sejas, Milton Pereira, Fabio Antônio Xavier
Surface tortuosity is a quantitative measure of the complexity of a material's surface. It is commonly defined as the ratio between the real length of the surface over the shortest distance between two points on the surface. An increase in surface tortuosity has been found to have advantageous effects on the durability of coated parts when exposed to corrosive and humid conditions. Laser surface texturing, a versatile process, can be used to modify the surface tortuosity by creating various structure patterns on the surface of steel. This study aims to investigate the impact of V-shaped groove dimensions on the resistance against corrosion creep of an organic coating applied to textured surfaces. Comparative surface tortuosity measurements were obtained for different groove dimensions while keeping the aspect ratio and textured areas constant. V-shaped grooves with an aspect ratio of 1 and sizes of 50, 100, and 200 μm were machined on carbon steel AISI-A36. The distance between adjacent grooves was varied to achieve different textured areas, ranging from 10% to 60%. The surface roughness (Sa) and surface tortuosity were characterized. The performance of the coating was evaluated using an accelerated corrosion test based on ISO 12944-9. The results indicate that V-shaped grooves with dimensions of 100 μm and a textured area of 40% exhibit the lowest coating delamination. It is worth to mention that the performance of organic coatings is enhanced up to a certain optimal point by an increase in surface tortuosity. However, beyond this optimal point, further increases in tortuosity do not lead to an increased resistance to the propagation of corrosion.
{"title":"Evaluation of surface tortuosity on the corrosion resistance of organic coatings using laser texturing process","authors":"Santiago Caraguay, Thiago Soares Pereira, Francisco Ratuznei, Miriam Zareth Parra Sejas, Milton Pereira, Fabio Antônio Xavier","doi":"10.2351/7.0001107","DOIUrl":"https://doi.org/10.2351/7.0001107","url":null,"abstract":"Surface tortuosity is a quantitative measure of the complexity of a material's surface. It is commonly defined as the ratio between the real length of the surface over the shortest distance between two points on the surface. An increase in surface tortuosity has been found to have advantageous effects on the durability of coated parts when exposed to corrosive and humid conditions. Laser surface texturing, a versatile process, can be used to modify the surface tortuosity by creating various structure patterns on the surface of steel. This study aims to investigate the impact of V-shaped groove dimensions on the resistance against corrosion creep of an organic coating applied to textured surfaces. Comparative surface tortuosity measurements were obtained for different groove dimensions while keeping the aspect ratio and textured areas constant. V-shaped grooves with an aspect ratio of 1 and sizes of 50, 100, and 200 μm were machined on carbon steel AISI-A36. The distance between adjacent grooves was varied to achieve different textured areas, ranging from 10% to 60%. The surface roughness (Sa) and surface tortuosity were characterized. The performance of the coating was evaluated using an accelerated corrosion test based on ISO 12944-9. The results indicate that V-shaped grooves with dimensions of 100 μm and a textured area of 40% exhibit the lowest coating delamination. It is worth to mention that the performance of organic coatings is enhanced up to a certain optimal point by an increase in surface tortuosity. However, beyond this optimal point, further increases in tortuosity do not lead to an increased resistance to the propagation of corrosion.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"5 2","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138603143","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}
S. Gruber, L. Stepien, L. Gerdt, E. López, Jan Kieser, F. Brueckner, Christoph Leyens, Craig Bratt
Copper is widely used in high heat flux and electrical applications because of its excellent electrical and thermal conductivity properties. Alloying elements such as chromium or nickel are added to strengthen the material, especially for higher temperatures. Cu4Cr2Nb, also known as GRCop-42, is a dispersion-strengthened copper-chromium-niobium alloy developed by NASA for high-temperature applications with high thermal and mechanical stresses such as rocket engines. Additive manufacturing (AM) enables applications with complex functionalized geometries and is particularly promising in the aerospace industry. In this contribution, a parametric study was performed for GRCop-42 and the AM process laser powder bed fusion (PBF-LB/M) using a green laser source for two-layer thicknesses of 30 and 60 μm. Density, electrical conductivity, hardness, microstructure, and static mechanical properties were analyzed. Various heat treatments ranging from 400 to 1000 °C and 30 min to 4 h were tested to increase the electrical conductivity and hardness. For both layer thicknesses, dense parameter sets could be obtained with resulting relative densities above 99.8%. Hardness and electrical conductivity could be tailored in the range of 103–219 HV2 and 24%–88% International Annealed Copper Standard (IACS) depending on the heat treatment. The highest ultimate tensile strength (UTS) obtained was 493 MPa. An aging temperature of 700 °C for 30 min showed the best combination of room temperature properties such as electrical conductivity of 83.76%IACS, UTS of 481 MPa, elongation at break (A) at 24%, and hardness of 125 HV2.
{"title":"Process development for laser powder bed fusion of GRCop-42 using a 515 nm laser source","authors":"S. Gruber, L. Stepien, L. Gerdt, E. López, Jan Kieser, F. Brueckner, Christoph Leyens, Craig Bratt","doi":"10.2351/7.0001139","DOIUrl":"https://doi.org/10.2351/7.0001139","url":null,"abstract":"Copper is widely used in high heat flux and electrical applications because of its excellent electrical and thermal conductivity properties. Alloying elements such as chromium or nickel are added to strengthen the material, especially for higher temperatures. Cu4Cr2Nb, also known as GRCop-42, is a dispersion-strengthened copper-chromium-niobium alloy developed by NASA for high-temperature applications with high thermal and mechanical stresses such as rocket engines. Additive manufacturing (AM) enables applications with complex functionalized geometries and is particularly promising in the aerospace industry. In this contribution, a parametric study was performed for GRCop-42 and the AM process laser powder bed fusion (PBF-LB/M) using a green laser source for two-layer thicknesses of 30 and 60 μm. Density, electrical conductivity, hardness, microstructure, and static mechanical properties were analyzed. Various heat treatments ranging from 400 to 1000 °C and 30 min to 4 h were tested to increase the electrical conductivity and hardness. For both layer thicknesses, dense parameter sets could be obtained with resulting relative densities above 99.8%. Hardness and electrical conductivity could be tailored in the range of 103–219 HV2 and 24%–88% International Annealed Copper Standard (IACS) depending on the heat treatment. The highest ultimate tensile strength (UTS) obtained was 493 MPa. An aging temperature of 700 °C for 30 min showed the best combination of room temperature properties such as electrical conductivity of 83.76%IACS, UTS of 481 MPa, elongation at break (A) at 24%, and hardness of 125 HV2.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"17 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139305331","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}
Jian Cheng, Feng Xie, Yulong Chen, Xingpeng Zhang, Zhongshen Zhai, Fengping Li, Dun Liu
Joining stainless steel to superalloy is currently of extensive interest for applications in aviation and automotive industries. However, conventional welding is prone to encounter defects such as cracks and austenite grain coarsening in the fusion zone. In the present study, laser welding was applied to join SUS304 stainless steel and Inconel718 superalloy circular tubes due to their precise local heat input and accuracy. The effects of defocusing distance, welding speed, and laser power on welding characteristics were studied by changing the values of the mentioned parameters, which manifested that different process parameters exerted a tremendous impact on the cross section morphology and shape of the weld seam. In addition, finite element simulation software was used to simulate temperature field distribution. The results revealed that there would be a buffering region on the temperature field once the laser power gradually decreased, which remarkably reflected the effect of the laser power descending on eliminating weld craters. Therefore, the crater defects caused by laser beam accelerating and decelerating at the start and end of welding could be effectively eliminated through synchronously regulating laser power in the real welding process.
{"title":"Butt welding of SUS304 and Inconel718 tubes by using defocused laser beam","authors":"Jian Cheng, Feng Xie, Yulong Chen, Xingpeng Zhang, Zhongshen Zhai, Fengping Li, Dun Liu","doi":"10.2351/7.0001086","DOIUrl":"https://doi.org/10.2351/7.0001086","url":null,"abstract":"Joining stainless steel to superalloy is currently of extensive interest for applications in aviation and automotive industries. However, conventional welding is prone to encounter defects such as cracks and austenite grain coarsening in the fusion zone. In the present study, laser welding was applied to join SUS304 stainless steel and Inconel718 superalloy circular tubes due to their precise local heat input and accuracy. The effects of defocusing distance, welding speed, and laser power on welding characteristics were studied by changing the values of the mentioned parameters, which manifested that different process parameters exerted a tremendous impact on the cross section morphology and shape of the weld seam. In addition, finite element simulation software was used to simulate temperature field distribution. The results revealed that there would be a buffering region on the temperature field once the laser power gradually decreased, which remarkably reflected the effect of the laser power descending on eliminating weld craters. Therefore, the crater defects caused by laser beam accelerating and decelerating at the start and end of welding could be effectively eliminated through synchronously regulating laser power in the real welding process.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"14 9","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135714561","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}
Ryan Mullennex, Wuji Huang, Casey Harwood, James Buchholz, Hongtao Ding
Air bubble injection has been a widely studied method for reducing frictional drag in fluid flows, especially in the marine industry. However, the lack of control over air bubble stability, size, and shape has hindered its widespread adoption. This study investigates the use of laser-based surface wettability modification techniques to address these challenges by enhancing control over air bubble behavior in water flows. We processed metal plates using nanosecond laser and chemical immersion to create wettability patterns consisting of regions of either superhydrophobicity or superhydrophilicity. Water tunnel experiments were conducted to observe the behavior of air bubbles over these different wettability patterns. The results revealed that surface wettability can be used to control the size and spatial distribution of air bubbles, which can enhance the energy cost-benefit of drag reduction methods in the marine industry. Moreover, this research offers new insights into the potential of laser-based surface wettability modification as a solution for improving the control of air bubble behavior in large-scale applications.
{"title":"Enhancing control of air bubbles in water flows through laser-based surface wettability patterning","authors":"Ryan Mullennex, Wuji Huang, Casey Harwood, James Buchholz, Hongtao Ding","doi":"10.2351/7.0001142","DOIUrl":"https://doi.org/10.2351/7.0001142","url":null,"abstract":"Air bubble injection has been a widely studied method for reducing frictional drag in fluid flows, especially in the marine industry. However, the lack of control over air bubble stability, size, and shape has hindered its widespread adoption. This study investigates the use of laser-based surface wettability modification techniques to address these challenges by enhancing control over air bubble behavior in water flows. We processed metal plates using nanosecond laser and chemical immersion to create wettability patterns consisting of regions of either superhydrophobicity or superhydrophilicity. Water tunnel experiments were conducted to observe the behavior of air bubbles over these different wettability patterns. The results revealed that surface wettability can be used to control the size and spatial distribution of air bubbles, which can enhance the energy cost-benefit of drag reduction methods in the marine industry. Moreover, this research offers new insights into the potential of laser-based surface wettability modification as a solution for improving the control of air bubble behavior in large-scale applications.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"121 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135714459","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}
In aerospace, thermal applications demand compact, lightweight, and efficient heat exchangers. Additive manufacturing processes offer the potential to create highly complex structures that are not achievable through traditional manufacturing methods. This work presents the development of an additively manufactured fluid-fluid heat exchanger that shows the potential to enhance the performance, reduce weight, and increase compactness compared to a conventional plate heat exchanger. A numerical model of the conventional plate heat exchanger was created, and fluid dynamics simulations with heat transfer were performed. Validation of the simulations was done by experiments. Then, a novel heat exchanger was designed using a bottom-up approach and investigated at different levels of complexity using computational fluid dynamics. The internal structure of the final heat exchanger consists of a repeating triply periodic Schwarz diamond minimum surface elongated in the direction of flow. The heat exchanger was manufactured with laser powder bed fusion process using AlSi10Mg. It had a 108% higher compactness and 54% lower weight compared to the plate heat exchanger. Numerical analysis yielded the pressure loss in pascal was reduced by 50%–59% while heat transfer in watts was improved by 3%–5%. Future researches should experimentally investigate the thermal and fluid mechanical characteristics of the novel additively manufactured heat exchanger and increase compactness and heat transfer further by analyzing the minimum partition wall thickness and the impact of wall roughness and deposit formation.
{"title":"Design and numerical assessment of an additively manufactured Schwarz diamond triply periodic minimal surface fluid-fluid heat exchanger","authors":"Tim Röver, Maxim Kuehne, Floyd Bischop, Leighton Clague, Bastian Bossen, Claus Emmelmann","doi":"10.2351/7.0001184","DOIUrl":"https://doi.org/10.2351/7.0001184","url":null,"abstract":"In aerospace, thermal applications demand compact, lightweight, and efficient heat exchangers. Additive manufacturing processes offer the potential to create highly complex structures that are not achievable through traditional manufacturing methods. This work presents the development of an additively manufactured fluid-fluid heat exchanger that shows the potential to enhance the performance, reduce weight, and increase compactness compared to a conventional plate heat exchanger. A numerical model of the conventional plate heat exchanger was created, and fluid dynamics simulations with heat transfer were performed. Validation of the simulations was done by experiments. Then, a novel heat exchanger was designed using a bottom-up approach and investigated at different levels of complexity using computational fluid dynamics. The internal structure of the final heat exchanger consists of a repeating triply periodic Schwarz diamond minimum surface elongated in the direction of flow. The heat exchanger was manufactured with laser powder bed fusion process using AlSi10Mg. It had a 108% higher compactness and 54% lower weight compared to the plate heat exchanger. Numerical analysis yielded the pressure loss in pascal was reduced by 50%–59% while heat transfer in watts was improved by 3%–5%. Future researches should experimentally investigate the thermal and fluid mechanical characteristics of the novel additively manufactured heat exchanger and increase compactness and heat transfer further by analyzing the minimum partition wall thickness and the impact of wall roughness and deposit formation.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"1 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139292511","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}
Laser cleaning is an advanced cleaning technology which is widely used in the manufacturing industry. Compared with the common planar laser cleaning process, the laser cleaning process of curved surface is difficult to control the completeness and homogeneity of the cleaning layer, which has a great influence on the surface quality and mechanical properties of the cleaned parts. Therefore, a three-dimensional numerical model of the laser cleaning process of the curved surface considering the coordinate system transformation of the heat source is established in this paper to clean the alumina on the surface of the 5754 aluminum alloy. The temperature distribution characteristics for different tangent slopes of the laser cleaning path and the temperature variation with time for different cleaning paths of the laser cleaning process are analyzed. The results show that the proposed method can provide important guiding significance for the practical laser cleaning process of the curved surface.
{"title":"Analysis for temperature distribution of laser cleaning process of curved surface by numerical simulation","authors":"Yuewei Ai, Guangyu Dong, Yachao Yan","doi":"10.2351/7.0001130","DOIUrl":"https://doi.org/10.2351/7.0001130","url":null,"abstract":"Laser cleaning is an advanced cleaning technology which is widely used in the manufacturing industry. Compared with the common planar laser cleaning process, the laser cleaning process of curved surface is difficult to control the completeness and homogeneity of the cleaning layer, which has a great influence on the surface quality and mechanical properties of the cleaned parts. Therefore, a three-dimensional numerical model of the laser cleaning process of the curved surface considering the coordinate system transformation of the heat source is established in this paper to clean the alumina on the surface of the 5754 aluminum alloy. The temperature distribution characteristics for different tangent slopes of the laser cleaning path and the temperature variation with time for different cleaning paths of the laser cleaning process are analyzed. The results show that the proposed method can provide important guiding significance for the practical laser cleaning process of the curved surface.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"66 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139303483","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}
Extreme high-speed directed energy deposition (EHLA) is a modified variant of the laser based directed energy deposition (DED-LB) and is being applied as an efficient coating process for rotational symmetric components. Characteristics of EHLA processes are feed rates of up to 200 m/min, which result in smaller weld bead deposition and thinner layer thicknesses compared to conventional DED-LB. When transferred to additive manufacturing, this characteristic utilizes the potential of depositing thin-walled filigree structures at deposition rates, which are comparable to typical DED-LB processes (EHLA3D). The results of this work were achieved with an EHLA3D machine, which is a modified CNC-type machine capable of operating feed rates with vf = 30 m/min. In this work, process parameters were developed for the deposition of thin-walled filigree structures with the Ni-based superalloy IN718. Single tracks with constant feed rates and a variation in the beam diameter and powder mass flow were deposited and analyzed regarding the resulting weld bead dimension and dilution zone. Then, process parameters were selected and transferred to the deposition of thin walls, and guidelines of the parameter adaption toward thin-walled deposition were defined. Two parameter sets were developed to assess the feasible wall-thicknesses deposited by EHLA3D. Depending on the developed parameter sets, wall thicknesses between 300 and 500 μm are achieved. To characterize the resulting thin-walls, surface roughness measurements and metallographic cross sections were conducted.
{"title":"Process development and process adaption guidelines for the deposition of thin-walled structures with IN718 using extreme high-speed directed energy deposition (EHLA3D)","authors":"Min-Uh Ko, Zongwei Zhang, Thomas Schopphoven","doi":"10.2351/7.0001140","DOIUrl":"https://doi.org/10.2351/7.0001140","url":null,"abstract":"Extreme high-speed directed energy deposition (EHLA) is a modified variant of the laser based directed energy deposition (DED-LB) and is being applied as an efficient coating process for rotational symmetric components. Characteristics of EHLA processes are feed rates of up to 200 m/min, which result in smaller weld bead deposition and thinner layer thicknesses compared to conventional DED-LB. When transferred to additive manufacturing, this characteristic utilizes the potential of depositing thin-walled filigree structures at deposition rates, which are comparable to typical DED-LB processes (EHLA3D). The results of this work were achieved with an EHLA3D machine, which is a modified CNC-type machine capable of operating feed rates with vf = 30 m/min. In this work, process parameters were developed for the deposition of thin-walled filigree structures with the Ni-based superalloy IN718. Single tracks with constant feed rates and a variation in the beam diameter and powder mass flow were deposited and analyzed regarding the resulting weld bead dimension and dilution zone. Then, process parameters were selected and transferred to the deposition of thin walls, and guidelines of the parameter adaption toward thin-walled deposition were defined. Two parameter sets were developed to assess the feasible wall-thicknesses deposited by EHLA3D. Depending on the developed parameter sets, wall thicknesses between 300 and 500 μm are achieved. To characterize the resulting thin-walls, surface roughness measurements and metallographic cross sections were conducted.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135371116","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}
Mohammad Hossein Razavi Dehkordi, Dheyaa J. Jasim, Ameer H. Al-Rubaye, Mohammad Akbari, Seyed Amin Bagherzadeh, Mohammadreza Ghazi, Hamed Mohammadkarimi
In this study, the experimental results of fiber laser cutting of Inconel 600 was modeled and optimized by combining artificial neural networks (ANNs) and particle swarm optimization (PSO). The impact of cutting criteria on the temperature adjacent to the cut kerf and roughness of the cutting edge was experimentally evaluated. The independent variables are the cutting speed, focal length, and laser power. The fiber laser cutting characteristics are modeled at different cutting conditions by the ANN method according to the experimental data. The findings indicated that the ANN is performing reasonably well in dealing with the training and test datasets. Also, the multiobjective PSO has been developed to effectively optimize the laser cutting procedure parameters in order to achieve the maximum temperature (the temperature upper than 370 °C) and minimum roughness (lower than 3 μm) simultaneously in order to improve the laser cutting efficiency. Based on the PSO results, the optimal laser power gained at a laser power of 830 and 1080 W at cutting speed ranges from 2 to 4 m/min and maximum focal length ranges between 0.75 and 0.8 mm where the lowest amount of roughness was created. The optimum temperature ranges were between 370 and 419°C. At a laser power of 1000 W and speed of 4 m/min, the smooth cutting edge at minimum roughness was gained without any defects. Transmission of the focal point up to 1.5 mm below the top surface of the sheet improved the roughness of the cutting edge and the cut quality by producing the smooth surface without slags.
{"title":"Modeling and multiobjective optimization of thermal effects of fiber laser cutting of Inconel 600 sheet by employing the ANN and multi-objective PSO algorithm","authors":"Mohammad Hossein Razavi Dehkordi, Dheyaa J. Jasim, Ameer H. Al-Rubaye, Mohammad Akbari, Seyed Amin Bagherzadeh, Mohammadreza Ghazi, Hamed Mohammadkarimi","doi":"10.2351/7.0001231","DOIUrl":"https://doi.org/10.2351/7.0001231","url":null,"abstract":"In this study, the experimental results of fiber laser cutting of Inconel 600 was modeled and optimized by combining artificial neural networks (ANNs) and particle swarm optimization (PSO). The impact of cutting criteria on the temperature adjacent to the cut kerf and roughness of the cutting edge was experimentally evaluated. The independent variables are the cutting speed, focal length, and laser power. The fiber laser cutting characteristics are modeled at different cutting conditions by the ANN method according to the experimental data. The findings indicated that the ANN is performing reasonably well in dealing with the training and test datasets. Also, the multiobjective PSO has been developed to effectively optimize the laser cutting procedure parameters in order to achieve the maximum temperature (the temperature upper than 370 °C) and minimum roughness (lower than 3 μm) simultaneously in order to improve the laser cutting efficiency. Based on the PSO results, the optimal laser power gained at a laser power of 830 and 1080 W at cutting speed ranges from 2 to 4 m/min and maximum focal length ranges between 0.75 and 0.8 mm where the lowest amount of roughness was created. The optimum temperature ranges were between 370 and 419°C. At a laser power of 1000 W and speed of 4 m/min, the smooth cutting edge at minimum roughness was gained without any defects. Transmission of the focal point up to 1.5 mm below the top surface of the sheet improved the roughness of the cutting edge and the cut quality by producing the smooth surface without slags.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"37 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135372163","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}
We investigated the laser-induced periodic surface structures (LIPSSs) formed on an SUS430 surface by irradiation with a nanosecond pulsed laser (Nd:YAG, wavelength of 532 nm, pulse width of 10 ns, number of pulses of 50, repetition rate of 10 Hz, and laser fluence of 1.2 J/cm2) and the antibacterial effect of the surface. LIPSSs with an interspacing of about 500 nm, which was close to the laser wavelength, were produced on the surface when the pulsed laser was near the ablation threshold. The film attachment method (JIS Z 2801) was used to measure the bacterial growth suppression on SUS430 surfaces with and without LIPSSs. On the surface without an LIPSS, the number of colonies was 1244, and on that with an LIPSS, the number was 198, indicating that the LIPSS formed by nanosecond pulsed laser irradiation inhibited the growth of bacteria. The chrome oxide layer on the SUS430 surface with the LIPSS may emit chrome ions from the edge of the LIPSS, enhancing the antibacterial effect.
{"title":"Antibacterial effect of periodic structure formed on SUS430 by using nanosecond pulsed laser","authors":"Mikuru Okazaki, Masaki Hashida, Satoru Iwamori","doi":"10.2351/7.0001196","DOIUrl":"https://doi.org/10.2351/7.0001196","url":null,"abstract":"We investigated the laser-induced periodic surface structures (LIPSSs) formed on an SUS430 surface by irradiation with a nanosecond pulsed laser (Nd:YAG, wavelength of 532 nm, pulse width of 10 ns, number of pulses of 50, repetition rate of 10 Hz, and laser fluence of 1.2 J/cm2) and the antibacterial effect of the surface. LIPSSs with an interspacing of about 500 nm, which was close to the laser wavelength, were produced on the surface when the pulsed laser was near the ablation threshold. The film attachment method (JIS Z 2801) was used to measure the bacterial growth suppression on SUS430 surfaces with and without LIPSSs. On the surface without an LIPSS, the number of colonies was 1244, and on that with an LIPSS, the number was 198, indicating that the LIPSS formed by nanosecond pulsed laser irradiation inhibited the growth of bacteria. The chrome oxide layer on the SUS430 surface with the LIPSS may emit chrome ions from the edge of the LIPSS, enhancing the antibacterial effect.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"191 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139295544","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. Kriegler, Tianran Liu, R. Hartl, Lucas Hille, M. F. Zaeh
Separating lithium metal foil into individual anodes is a critical process step in all-solid-state battery production. With the use of nanosecond-pulsed laser cutting, a characteristic quality-decisive cut edge geometry is formed depending on the chosen parameter set. This cut edge can be characterized by micrometer-scale imaging techniques such as confocal laser scanning microscopy. Currently, experimental determination of suitable process parameters is time-consuming and biased by the human measurement approach, while no methods for automated quality assurance are known. This study presents a deep-learning computer vision approach for geometry characterization of lithium foil laser cut edges. The convolutional neural network architecture Mask R-CNN was implemented and applied for categorizing confocal laser scanning microscopy images showing defective and successful cuts, achieving a classification precision of more than 95%. The algorithm was trained for automatic pixel-wise segmentation of the quality-relevant melt superelevation along the cut edge, reaching segmentation accuracies of up to 88%. Influence of the training data set size on the classification and segmentation accuracies was assessed confirming the algorithm’s industrial application potential due to the low number of 246 or fewer original images required. The segmentation masks were combined with topography data of cut edges to obtain quantitative metrics for the quality evaluation of lithium metal electrodes. The presented computer vision pipeline enables the integration of an automated image evaluation for quality inspection of lithium foil laser cutting, promoting industrial production of all-solid-state batteries with lithium metal anode.
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