Qamar Hayat, Pasquale Franciosa, Giovanni Chianese, Anand Mohan, Dariusz Ceglarek, Alexander Griffiths, Christopher Harris
In the attempt to produce lighter battery packs at a lower cost, replacing common copper parts with aluminum components has been a popular approach in recent years. With regard to joining technologies, there is a growing interest in applying laser beam welding in battery pack manufacturing due to several advantages such as single-sided and noncontact access while maintaining a narrow heat-affected zone. Motivated by the need to control and reduce weld porosity in AA1060 battery busbar welding with the ultimate goal to enhance durability and reduce electrical resistance, this paper has been developed with the aim to studying the effect of laser beam shaping on porosity formation and, hence, generate knowledge about the underlying physics of the welding process itself. First, a multiphysics computational fluid dynamics model has been developed and calibrated to experimental data; then, the model has been deployed to study the effect of both circular and tailing beam shapes on melt pool dynamics and the evolution of porosity due to the instability of the keyhole. The study elucidated the importance of the keyhole’s necking on porosity formation. Findings showed that the tail beam shapes, compared to the circular spot, have a pronounced effect on the reduction of the necking effect of the keyhole—this helps to reduce number of collapsing events of the keyhole itself, thereby leading to the reduction of porosity formation.
{"title":"Elucidating the effect of circular and tailing laser beam shapes on keyhole necking and porosity formation during laser beam welding of aluminum 1060 using a multiphysics computational fluid dynamics approach","authors":"Qamar Hayat, Pasquale Franciosa, Giovanni Chianese, Anand Mohan, Dariusz Ceglarek, Alexander Griffiths, Christopher Harris","doi":"10.2351/7.0001150","DOIUrl":"https://doi.org/10.2351/7.0001150","url":null,"abstract":"In the attempt to produce lighter battery packs at a lower cost, replacing common copper parts with aluminum components has been a popular approach in recent years. With regard to joining technologies, there is a growing interest in applying laser beam welding in battery pack manufacturing due to several advantages such as single-sided and noncontact access while maintaining a narrow heat-affected zone. Motivated by the need to control and reduce weld porosity in AA1060 battery busbar welding with the ultimate goal to enhance durability and reduce electrical resistance, this paper has been developed with the aim to studying the effect of laser beam shaping on porosity formation and, hence, generate knowledge about the underlying physics of the welding process itself. First, a multiphysics computational fluid dynamics model has been developed and calibrated to experimental data; then, the model has been deployed to study the effect of both circular and tailing beam shapes on melt pool dynamics and the evolution of porosity due to the instability of the keyhole. The study elucidated the importance of the keyhole’s necking on porosity formation. Findings showed that the tail beam shapes, compared to the circular spot, have a pronounced effect on the reduction of the necking effect of the keyhole—this helps to reduce number of collapsing events of the keyhole itself, thereby leading to the reduction of porosity formation.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135967882","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 structuring can be applied to composite electrodes of lithium-ion cells to enhance wetting and to facilitate the usage of thick-film electrodes by reducing the lithium-ion diffusion overpotential and the tortuosity of the electrodes or the usage of electrodes containing silicon, where additional porosity is required to compensate the volume expansion during lithium de-/insertion. To integrate the additional laser processing step in the well-established electrode manufacturing route, the laser processing speed must be significantly increased to match with the belt speed, which is dependent on the electrode thickness and the type of manufacturing route. Upscaling can be realized by increasing the average laser power, laser intensity, and/or laser repetition rate. Here, an ultrashort pulsed laser source with an average power of 300 W and a pulse duration of 600 fs was applied. For the first time, the presented research provides detailed laser ablation processing data for thick-film composite anodes associated with high repetition rates ranging from 4.9 to 48.8 MHz. The patterning results are compared depending on the widths, depths, aspect ratios, the total appearance regarding debris and cracks, and the volume ablation rate. In high repetition rate laser patterning, the subsequent laser pulses interact with the material vapor plasma generated by the previous laser pulses, resulting in lower ablation depths and higher ablation widths. The increase in laser peak intensity leads to higher achievable ablation depths. Processing strategies are identified for two different ablation scenarios focusing on the pouch cells of a Volkswagen ID.3 and the Tesla 4680 cell.
{"title":"High repetition ultrafast laser ablation of graphite and silicon/graphite composite electrodes for lithium-ion batteries","authors":"Alexandra Meyer, Yannic Sterzl, Wilhelm Pfleging","doi":"10.2351/7.0001180","DOIUrl":"https://doi.org/10.2351/7.0001180","url":null,"abstract":"Laser structuring can be applied to composite electrodes of lithium-ion cells to enhance wetting and to facilitate the usage of thick-film electrodes by reducing the lithium-ion diffusion overpotential and the tortuosity of the electrodes or the usage of electrodes containing silicon, where additional porosity is required to compensate the volume expansion during lithium de-/insertion. To integrate the additional laser processing step in the well-established electrode manufacturing route, the laser processing speed must be significantly increased to match with the belt speed, which is dependent on the electrode thickness and the type of manufacturing route. Upscaling can be realized by increasing the average laser power, laser intensity, and/or laser repetition rate. Here, an ultrashort pulsed laser source with an average power of 300 W and a pulse duration of 600 fs was applied. For the first time, the presented research provides detailed laser ablation processing data for thick-film composite anodes associated with high repetition rates ranging from 4.9 to 48.8 MHz. The patterning results are compared depending on the widths, depths, aspect ratios, the total appearance regarding debris and cracks, and the volume ablation rate. In high repetition rate laser patterning, the subsequent laser pulses interact with the material vapor plasma generated by the previous laser pulses, resulting in lower ablation depths and higher ablation widths. The increase in laser peak intensity leads to higher achievable ablation depths. Processing strategies are identified for two different ablation scenarios focusing on the pouch cells of a Volkswagen ID.3 and the Tesla 4680 cell.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136012565","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}
Kiran Michael, Lukas Greiner, Philip Dreizehnter, Jodok Weixler, Matthias Putzer, Timo Schudeleit, Markus Bambach, Konrad Wegener
This study investigates the feasibility of using ultra-short pulsed (USP) lasers to fabricate single crystalline diamond (SCD) tools. SCD has exceptional mechanical, tribological, and thermal properties and offers excellent performance in the precision machining of hard and brittle materials over polycrystalline diamond and diamond-coated tools. However, the anisotropic nature of the SCD makes it difficult for laser machining because the material shows susceptibility to cracking, defect growth, and breakout depending on its crystallographic orientation. Anisotropy needs to be considered while optimizing the geometry of the tool to minimize wear and improve tool performance. An advanced four-axis laser machining approach with optimized laser parameters and temporal beam shaping is used to mitigate challenges related to defect growth and orientation dependence, leading to the production of high-quality single cutting-edge SCD tools. Cylindrical diamonds and diamond crystals with top surface planes {100} and {111} are used in the study. The occurrence of defects in the diamond when laser machined and their dependence on the crystallographic orientation along the circumference of the diamond is thoroughly investigated via SEM, electron backscatter diffraction, and light microscopy images. Finally, the laser-manufactured SCD tools are tested by turning fully sintered zirconia ceramics (3Y-TZP-A). USP laser machining of SCD is demonstrated to be a viable alternative to traditional manufacturing methods for producing high-quality SCD tools with unique properties and performance. The results further emphasize the importance of understanding the crystallographic orientation dependence when laser machining crystalline materials like diamonds.
{"title":"Ultra-short pulsed laser processing of single crystalline diamonds for tooling applications","authors":"Kiran Michael, Lukas Greiner, Philip Dreizehnter, Jodok Weixler, Matthias Putzer, Timo Schudeleit, Markus Bambach, Konrad Wegener","doi":"10.2351/7.0001159","DOIUrl":"https://doi.org/10.2351/7.0001159","url":null,"abstract":"This study investigates the feasibility of using ultra-short pulsed (USP) lasers to fabricate single crystalline diamond (SCD) tools. SCD has exceptional mechanical, tribological, and thermal properties and offers excellent performance in the precision machining of hard and brittle materials over polycrystalline diamond and diamond-coated tools. However, the anisotropic nature of the SCD makes it difficult for laser machining because the material shows susceptibility to cracking, defect growth, and breakout depending on its crystallographic orientation. Anisotropy needs to be considered while optimizing the geometry of the tool to minimize wear and improve tool performance. An advanced four-axis laser machining approach with optimized laser parameters and temporal beam shaping is used to mitigate challenges related to defect growth and orientation dependence, leading to the production of high-quality single cutting-edge SCD tools. Cylindrical diamonds and diamond crystals with top surface planes {100} and {111} are used in the study. The occurrence of defects in the diamond when laser machined and their dependence on the crystallographic orientation along the circumference of the diamond is thoroughly investigated via SEM, electron backscatter diffraction, and light microscopy images. Finally, the laser-manufactured SCD tools are tested by turning fully sintered zirconia ceramics (3Y-TZP-A). USP laser machining of SCD is demonstrated to be a viable alternative to traditional manufacturing methods for producing high-quality SCD tools with unique properties and performance. The results further emphasize the importance of understanding the crystallographic orientation dependence when laser machining crystalline materials like diamonds.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"40 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135967751","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}
Laura Budde, Nick Schwarz, Jörg Hermsdorf, Stefan Kaierle, Ludger Overmeyer
In this study, the application of the ABA cladding strategy in coaxial wire-based cladding processes is investigated. Individual weld seams (A) are first welded on the substrate and additional weld seams (B) are deposited into the intermediate spaces in the second step. Thereby, two different seam geometries are present in the cladding. Unidirectional AAA and ABA claddings are generated using laser hot-wire cladding and analyzed with respect to the quality criteria height, waviness, degree of dilution, and defects. Three different welding parameter sets are used to consider the effect of the contact angle on the applicability of the ABA cladding strategy. When the same process parameters and seam-to-seam offsets are used for the ABA cladding, as for the AAA cladding, the B weld seams are higher than the A weld seams and an uneven ridged cladding surface is present. Two approaches to solving this problem are considered. The cross-sectional area of the B weld seams is reduced by adjusting the welding speeds or an increase in the seam-to-seam offset. Both measures result in a significant reduction in waviness of 30%–58% compared to the AAA cladding. However, lack of fusion defects occurs more frequently at the deposition regime of the B weld seams. It was, therefore, necessary to adjust the process parameters for weld seam B.
{"title":"Application of the ABA cladding technique to a wire based laser cladding process","authors":"Laura Budde, Nick Schwarz, Jörg Hermsdorf, Stefan Kaierle, Ludger Overmeyer","doi":"10.2351/7.0001115","DOIUrl":"https://doi.org/10.2351/7.0001115","url":null,"abstract":"In this study, the application of the ABA cladding strategy in coaxial wire-based cladding processes is investigated. Individual weld seams (A) are first welded on the substrate and additional weld seams (B) are deposited into the intermediate spaces in the second step. Thereby, two different seam geometries are present in the cladding. Unidirectional AAA and ABA claddings are generated using laser hot-wire cladding and analyzed with respect to the quality criteria height, waviness, degree of dilution, and defects. Three different welding parameter sets are used to consider the effect of the contact angle on the applicability of the ABA cladding strategy. When the same process parameters and seam-to-seam offsets are used for the ABA cladding, as for the AAA cladding, the B weld seams are higher than the A weld seams and an uneven ridged cladding surface is present. Two approaches to solving this problem are considered. The cross-sectional area of the B weld seams is reduced by adjusting the welding speeds or an increase in the seam-to-seam offset. Both measures result in a significant reduction in waviness of 30%–58% compared to the AAA cladding. However, lack of fusion defects occurs more frequently at the deposition regime of the B weld seams. It was, therefore, necessary to adjust the process parameters for weld seam B.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136012733","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}
The processability of pure Inconel X750 and Inconel X750 mixed with 15 vol. % of titanium carbide particulate through laser-directed energy deposition (l-DED) was evaluated. The powders used had a particle size in a range unusual to l-DED processing (0.18–24.05 μm); this case study presents difficulties in processing thin quadri-modal powder and describes possible measures to mitigate them, while also reporting, likely for the first time, on the l-DED processing of Inconel X750 and such related metal matrix composite (MMC). The choice in reinforcement particle size and composition aimed for a reduction in material density and insertion of additional reinforcement mechanisms. Both powders used were analyzed in an FT4 rheometer and compared to reference Inconel 625 powder. l-DED was made viable, but results show that the powders tested here represent a lower limit for the rheological properties accepted by usual l-DED systems. A methodology to quantify the stability of a given processing condition is presented and validated, also indicating that low powder flows are recommended when processing powders of this sort. Inconel X750 demonstrated sensibility to oxidation during processing as depletion of Al and Ti was detected in the deposits. Neither the MMC nor the pure material cracked or showed excessive porosity.
{"title":"Processability of thin-powdered Inconel X750 and TiC metal matrix composite by laser-directed energy deposition","authors":"Adriano de Souza Pinto Pereira, Jhonattan Gutjahr, Milton Pereira, Ulrich Tetzlaff, Márcio Celso Fredel","doi":"10.2351/7.0001134","DOIUrl":"https://doi.org/10.2351/7.0001134","url":null,"abstract":"The processability of pure Inconel X750 and Inconel X750 mixed with 15 vol. % of titanium carbide particulate through laser-directed energy deposition (l-DED) was evaluated. The powders used had a particle size in a range unusual to l-DED processing (0.18–24.05 μm); this case study presents difficulties in processing thin quadri-modal powder and describes possible measures to mitigate them, while also reporting, likely for the first time, on the l-DED processing of Inconel X750 and such related metal matrix composite (MMC). The choice in reinforcement particle size and composition aimed for a reduction in material density and insertion of additional reinforcement mechanisms. Both powders used were analyzed in an FT4 rheometer and compared to reference Inconel 625 powder. l-DED was made viable, but results show that the powders tested here represent a lower limit for the rheological properties accepted by usual l-DED systems. A methodology to quantify the stability of a given processing condition is presented and validated, also indicating that low powder flows are recommended when processing powders of this sort. Inconel X750 demonstrated sensibility to oxidation during processing as depletion of Al and Ti was detected in the deposits. Neither the MMC nor the pure material cracked or showed excessive porosity.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136013145","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}
Woo-In Choo, Yoo-Eun Lee, Sungbin Im, Minsun Oh, Dongchoul Kim, Dong Hyuck Kam
Automotive lamps have not only functional roles but also highly esthetic purposes in the design of a car. As such, they use complex three-dimensional shapes to implement various designs. The main manufacturing challenge comes from the plastic bonding process of the complex components, which currently is done by thermal bonding, ultrasonic bonding, and laser welding. Laser welding processes with a narrow joint area are preferred since they require minimal joint area and produce no burr. In this study, an optimization study for simultaneous bonding of lamps is carried out using multiple light sources generated by connecting specially manufactured bundle optical fibers with a diode laser source. The diode laser beams with a wavelength of 915 nm and a power of 80 W, each, were simultaneously delivered through a 30-optical fibers bundle. The fibers were integrated within the mold that holds the lamp achieving transmission welding through the overlapped upper transparent polymer PMMA (IF850) and the lower nontransparent polymer ABS (HL121H). The process parameters investigated were the laser power, duration time, waveguide gap, and clamping pressure. We present optimized process parameters that achieved no pores and relatively uniform melting. In the shear test, the average load was approximately 1300 N, and the base sheet fractures along the welding joints were observed.
{"title":"Experimental evaluation of poly methyl methacrylate-acrylonitrile butadiene styrene transmission welding using mold-integrated simultaneous laser welding technology","authors":"Woo-In Choo, Yoo-Eun Lee, Sungbin Im, Minsun Oh, Dongchoul Kim, Dong Hyuck Kam","doi":"10.2351/7.0001144","DOIUrl":"https://doi.org/10.2351/7.0001144","url":null,"abstract":"Automotive lamps have not only functional roles but also highly esthetic purposes in the design of a car. As such, they use complex three-dimensional shapes to implement various designs. The main manufacturing challenge comes from the plastic bonding process of the complex components, which currently is done by thermal bonding, ultrasonic bonding, and laser welding. Laser welding processes with a narrow joint area are preferred since they require minimal joint area and produce no burr. In this study, an optimization study for simultaneous bonding of lamps is carried out using multiple light sources generated by connecting specially manufactured bundle optical fibers with a diode laser source. The diode laser beams with a wavelength of 915 nm and a power of 80 W, each, were simultaneously delivered through a 30-optical fibers bundle. The fibers were integrated within the mold that holds the lamp achieving transmission welding through the overlapped upper transparent polymer PMMA (IF850) and the lower nontransparent polymer ABS (HL121H). The process parameters investigated were the laser power, duration time, waveguide gap, and clamping pressure. We present optimized process parameters that achieved no pores and relatively uniform melting. In the shear test, the average load was approximately 1300 N, and the base sheet fractures along the welding joints were observed.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135591158","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}
Pascal Paulus, Yannick Ruppert, Michael Vielhaber, Juergen Griebsch
Powder-based laser metal deposition (LMD) offers a promising additive manufacturing process, given the large number of available materials for cladding or generative applications. In laser cladding of dissimilar materials, it is necessary to control the mixing of substrate and additive in the interaction zone to ensure safe metallurgical bonding while avoiding critical chemical compositions that lead to undesired phase precipitation. However, the generation of empirical data for LMD process development is very challenging and time-consuming. In this context, different machine learning models are examined to identify whether they can converge with a small amount of empirical data. In this work, the prediction accuracy of back propagation neural network (BPNN), long short-term memory (LSTM), and extreme gradient boosting (XGBoost) was compared using mean squared error (MSE) and mean absolute percentage error (MAPE). A hyperparameter optimization was performed for each model. The materials used are 316L as the substrate and VDM Alloy 780 as the additive. The dataset used consists of 40 empirically determined values. The input parameters are laser power, feed rate, and powder mass flow rate. The quality characteristics of height, width, dilution, Fe-amount, and seam contour are defined as outputs. As a result, the predictions were compared with retained validation data and described as MSE and MAPE to determine the prediction accuracy for the models. BPNN achieved a prediction accuracy of 0.0072 MSE and 4.37% MAPE and XGBoost of 0.0084 MSE and 6.34% MAPE. The most accurate prediction was achieved by LSTM with 0.0053 MSE and 3.75% MAPE.
{"title":"Prediction of single track clad quality in laser metal deposition using dissimilar materials: Comparison of machine learning-based approaches","authors":"Pascal Paulus, Yannick Ruppert, Michael Vielhaber, Juergen Griebsch","doi":"10.2351/7.0001108","DOIUrl":"https://doi.org/10.2351/7.0001108","url":null,"abstract":"Powder-based laser metal deposition (LMD) offers a promising additive manufacturing process, given the large number of available materials for cladding or generative applications. In laser cladding of dissimilar materials, it is necessary to control the mixing of substrate and additive in the interaction zone to ensure safe metallurgical bonding while avoiding critical chemical compositions that lead to undesired phase precipitation. However, the generation of empirical data for LMD process development is very challenging and time-consuming. In this context, different machine learning models are examined to identify whether they can converge with a small amount of empirical data. In this work, the prediction accuracy of back propagation neural network (BPNN), long short-term memory (LSTM), and extreme gradient boosting (XGBoost) was compared using mean squared error (MSE) and mean absolute percentage error (MAPE). A hyperparameter optimization was performed for each model. The materials used are 316L as the substrate and VDM Alloy 780 as the additive. The dataset used consists of 40 empirically determined values. The input parameters are laser power, feed rate, and powder mass flow rate. The quality characteristics of height, width, dilution, Fe-amount, and seam contour are defined as outputs. As a result, the predictions were compared with retained validation data and described as MSE and MAPE to determine the prediction accuracy for the models. BPNN achieved a prediction accuracy of 0.0072 MSE and 4.37% MAPE and XGBoost of 0.0084 MSE and 6.34% MAPE. The most accurate prediction was achieved by LSTM with 0.0053 MSE and 3.75% MAPE.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135696500","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}
Haixing Liu, Jie Xu, Haojian He, Chao Wu, Jing Liu, Xiuquan He, Xizhao Wang
Micropores fabricated on organic polymer films have a wide range of applications in fields such as microfiltration, new energy, and biomedical separation. The use of laser processing technology can complete the processing of micropores on the surface of ultrathin films with high precision, but there is still some difficulty in the processing of ultrathick films. In this paper, a picosecond ultraviolet (UV) laser was used to explore the high-precision manufacturing process of micropores on the surface of ultrathick polyimide (PI) films. The effects of laser power, laser frequency, and scanning speed on the cone angle and spatter deposition area of micropores’ fabrication on ultrathick PI were studied based on orthogonal experiments. The mechanism of processing micropores on ultrathick PI was analyzed by studying the deposition area and morphology of the spatter generated during the laser ablation process. It was found that high-quality micropores can be fabricated at low laser frequency and high power.
{"title":"Optimization of micropore fabrication on the surface of ultrathick polyimide film based on picosecond UV laser","authors":"Haixing Liu, Jie Xu, Haojian He, Chao Wu, Jing Liu, Xiuquan He, Xizhao Wang","doi":"10.2351/7.0001070","DOIUrl":"https://doi.org/10.2351/7.0001070","url":null,"abstract":"Micropores fabricated on organic polymer films have a wide range of applications in fields such as microfiltration, new energy, and biomedical separation. The use of laser processing technology can complete the processing of micropores on the surface of ultrathin films with high precision, but there is still some difficulty in the processing of ultrathick films. In this paper, a picosecond ultraviolet (UV) laser was used to explore the high-precision manufacturing process of micropores on the surface of ultrathick polyimide (PI) films. The effects of laser power, laser frequency, and scanning speed on the cone angle and spatter deposition area of micropores’ fabrication on ultrathick PI were studied based on orthogonal experiments. The mechanism of processing micropores on ultrathick PI was analyzed by studying the deposition area and morphology of the spatter generated during the laser ablation process. It was found that high-quality micropores can be fabricated at low laser frequency and high power.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135697302","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}
The spatter is one of the defect factors for laser welding. For high-quality laser welding, the elucidation of the spatter reduction mechanism is required. In our previous study, it was elucidated that the molten pool and keyhole fluctuation contribute to spatter generation from the observation of the keyhole and molten pool under different ambient pressure conditions. However, the main cause of the instability of the molten pool and keyhole has not been clarified. It is considered that the interaction between the laser and plume might cause these instabilities. Therefore, in this study, we focused on the plume generated by laser irradiation. The dynamics of the plume during laser welding and the attenuation of the laser were observed under different ambient pressures. According to these observations, the effect of the plume on instability in laser welding was elucidated. The SS304 was fixed in the vacuum chamber, and the disk laser with an output power of 6 kW swept on the sample to form the weld bead. At the same time, the plume behavior was observed by the Schlieren method, and the attenuation of the laser was measured using a probe laser. As a result, the metal vapor jet, which is a periodical plume ejection, was observed. The attenuation of the probe laser increased with increasing atmospheric pressure. These results suggest that the frequent generation of the metal vapor jet under atmospheric pressure caused instability in the heat input of the laser, which caused instability in the keyhole and molten pool.
{"title":"Influence of the laser-induced plume on welding behavior in keyhole welding for stainless steel using a 16 kW disk laser","authors":"Yoshiaki Kurita, Yuji Sato, Shumpei Fujio, Masami Mizutani, Masahiro Tsukamoto","doi":"10.2351/7.0001173","DOIUrl":"https://doi.org/10.2351/7.0001173","url":null,"abstract":"The spatter is one of the defect factors for laser welding. For high-quality laser welding, the elucidation of the spatter reduction mechanism is required. In our previous study, it was elucidated that the molten pool and keyhole fluctuation contribute to spatter generation from the observation of the keyhole and molten pool under different ambient pressure conditions. However, the main cause of the instability of the molten pool and keyhole has not been clarified. It is considered that the interaction between the laser and plume might cause these instabilities. Therefore, in this study, we focused on the plume generated by laser irradiation. The dynamics of the plume during laser welding and the attenuation of the laser were observed under different ambient pressures. According to these observations, the effect of the plume on instability in laser welding was elucidated. The SS304 was fixed in the vacuum chamber, and the disk laser with an output power of 6 kW swept on the sample to form the weld bead. At the same time, the plume behavior was observed by the Schlieren method, and the attenuation of the laser was measured using a probe laser. As a result, the metal vapor jet, which is a periodical plume ejection, was observed. The attenuation of the probe laser increased with increasing atmospheric pressure. These results suggest that the frequent generation of the metal vapor jet under atmospheric pressure caused instability in the heat input of the laser, which caused instability in the keyhole and molten pool.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135739279","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}
Ziang Chen, Ruoyu Zhai, Yuyao Cai, Yanpeng Ye, Zhongmou Sun, Yuzhu Liu
Paper is a widely used material and common recyclable household waste in waste disposal, which gets more attention nowadays for the misclassification of recyclable waste. In this work, an online source tracing system combined with machine learning algorithms to identify and classify the smoke of waste paper incineration based on laser-induced breakdown spectroscopy (LIBS) was established. Four types of waste paper, including tissue, corrugated paper, printing paper, and newspaper, were taken as examples. The smoke of four different waste papers was detected by LIBS and then further analyzed. The detected spectra with C, N, O, Mg, Al, and Ca could hardly be distinguished artificially. The random forest algorithm and the linear discriminant analysis were introduced to classify the smoke, and its accuracy reached 95.83%. The results indicate that source tracing of waste paper can be realized by identifying and classifying the smoke via the developed system. This could provide some reference for helping us to monitor the effectiveness of waste classification and incineration and monitor the atmosphere pollution.
{"title":"Online source tracing of waste paper by smoke based on laser-induced breakdown spectroscopy","authors":"Ziang Chen, Ruoyu Zhai, Yuyao Cai, Yanpeng Ye, Zhongmou Sun, Yuzhu Liu","doi":"10.2351/7.0001226","DOIUrl":"https://doi.org/10.2351/7.0001226","url":null,"abstract":"Paper is a widely used material and common recyclable household waste in waste disposal, which gets more attention nowadays for the misclassification of recyclable waste. In this work, an online source tracing system combined with machine learning algorithms to identify and classify the smoke of waste paper incineration based on laser-induced breakdown spectroscopy (LIBS) was established. Four types of waste paper, including tissue, corrugated paper, printing paper, and newspaper, were taken as examples. The smoke of four different waste papers was detected by LIBS and then further analyzed. The detected spectra with C, N, O, Mg, Al, and Ca could hardly be distinguished artificially. The random forest algorithm and the linear discriminant analysis were introduced to classify the smoke, and its accuracy reached 95.83%. The results indicate that source tracing of waste paper can be realized by identifying and classifying the smoke via the developed system. This could provide some reference for helping us to monitor the effectiveness of waste classification and incineration and monitor the atmosphere pollution.","PeriodicalId":50168,"journal":{"name":"Journal of Laser Applications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135738542","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：