Pub Date : 2026-06-01Epub Date: 2025-12-17DOI: 10.1016/j.jajp.2025.100368
Johannes Gerritzen , Kunal Chopra , Gregor Reschke , Andreas Hornig , Alexander Brosius , Maik Gude
Quality assurance (QA) of clinched joints is predominantly performed by destructive testing. Recently, non-destructive evaluation (NDE) methods received increasing attention as a potential alternative. However, the inherently indirect measurement of underlying effects poses a significant challenge to its broader application. To tackle this, two experimental data sets, containing a total of 43 potential process deviations and defects are established using transient dynamic analysis (TDA). On these, several machine learning (ML) models are trained to detect the underlying deviations. The best-in-class model is used to identify a frequency band at which a classification accuracy of 88.58% across all 43 classes is achieved. Further analysis of the most discriminative model features reveals the importance of measuring both excitation as well as specimen response. This lays the foundation for further research towards defect specific in-line measurements of mechanical joints, further improving joint reliability.
{"title":"Quality assurance of clinched joints using explainable machine learning","authors":"Johannes Gerritzen , Kunal Chopra , Gregor Reschke , Andreas Hornig , Alexander Brosius , Maik Gude","doi":"10.1016/j.jajp.2025.100368","DOIUrl":"10.1016/j.jajp.2025.100368","url":null,"abstract":"<div><div>Quality assurance (QA) of clinched joints is predominantly performed by destructive testing. Recently, non-destructive evaluation (NDE) methods received increasing attention as a potential alternative. However, the inherently indirect measurement of underlying effects poses a significant challenge to its broader application. To tackle this, two experimental data sets, containing a total of 43 potential process deviations and defects are established using transient dynamic analysis (TDA). On these, several machine learning (ML) models are trained to detect the underlying deviations. The best-in-class model is used to identify a frequency band at which a classification accuracy of 88.58% across all 43 classes is achieved. Further analysis of the most discriminative model features reveals the importance of measuring both excitation as well as specimen response. This lays the foundation for further research towards defect specific in-line measurements of mechanical joints, further improving joint reliability.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100368"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-04DOI: 10.1016/j.jajp.2026.100379
Stefan Donaubauer, Raphael Schmid, Stefan Weihe, Martin Werz
Manufacturing deviations, assembly inaccuracies, and tolerances can create joint gaps that challenge conventional friction stir welding (FSW), which typically requires a tight fit-up to avoid issues such as tunnel defects, surface grooves, or insufficient bonding. In this study, a wire-based friction stir welding (W-FSW) approach using a stationary-shoulder multi-pin tool with an integrated extrusion-screw pin is presented to continuously feed EN AW-6063 aluminium filler wire into the joint. The filler wire is mechanically segmented, pre-plasticised within the tool, and intensively stirred into the substrate, enabling effective gap filling and a uniform material distribution in the weld zone. Gap widths of up to 4 mm, corresponding to 200% of the base material thickness, were successfully bridged, representing an extreme gap condition for thin-sheet aluminium joining, resulting in fully filled joints with a smooth and well-consolidated weld surface across all investigated gap widths. No weld undercuts or surface-related imperfections were observed. Electron backscatter diffraction (EBSD) analysis revealed a refined and stable microstructure. The weld nugget consistently exhibited grain sizes of 12–15 m, independent of gap width, while the thermo-mechanically affected zone and heat-affected zone remained nearly constant at 29–30 m (base material: 32 m). Tensile testing yielded an average ultimate tensile strength of 155 MPa with ductility comparable to reference joints, with fracture consistently occurring in the heat-affected zone, indicating stable mechanical performance despite the large joint gaps. Overall, the results demonstrate that multi-pin W-FSW provides a gap-tolerant and robust solid-state joining approach, significantly extending the practical application range of friction stir welding for EN AW-6063.
{"title":"Bridgeability of large gaps in EN AW-6063 aluminium alloy by wire-based friction stir welding with a multi-pin tool","authors":"Stefan Donaubauer, Raphael Schmid, Stefan Weihe, Martin Werz","doi":"10.1016/j.jajp.2026.100379","DOIUrl":"10.1016/j.jajp.2026.100379","url":null,"abstract":"<div><div>Manufacturing deviations, assembly inaccuracies, and tolerances can create joint gaps that challenge conventional friction stir welding (FSW), which typically requires a tight fit-up to avoid issues such as tunnel defects, surface grooves, or insufficient bonding. In this study, a wire-based friction stir welding (W-FSW) approach using a stationary-shoulder multi-pin tool with an integrated extrusion-screw pin is presented to continuously feed EN AW-6063 aluminium filler wire into the joint. The filler wire is mechanically segmented, pre-plasticised within the tool, and intensively stirred into the substrate, enabling effective gap filling and a uniform material distribution in the weld zone. Gap widths of up to 4 mm, corresponding to 200% of the base material thickness, were successfully bridged, representing an extreme gap condition for thin-sheet aluminium joining, resulting in fully filled joints with a smooth and well-consolidated weld surface across all investigated gap widths. No weld undercuts or surface-related imperfections were observed. Electron backscatter diffraction (EBSD) analysis revealed a refined and stable microstructure. The weld nugget consistently exhibited grain sizes of 12–15 <span><math><mi>μ</mi></math></span>m, independent of gap width, while the thermo-mechanically affected zone and heat-affected zone remained nearly constant at 29–30 <span><math><mi>μ</mi></math></span>m (base material: 32 <span><math><mi>μ</mi></math></span>m). Tensile testing yielded an average ultimate tensile strength of 155 MPa with ductility comparable to reference joints, with fracture consistently occurring in the heat-affected zone, indicating stable mechanical performance despite the large joint gaps. Overall, the results demonstrate that multi-pin W-FSW provides a gap-tolerant and robust solid-state joining approach, significantly extending the practical application range of friction stir welding for EN AW-6063.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100379"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-09DOI: 10.1016/j.jajp.2026.100375
V Ginster , A Weigert , MK Heym , CJA Beier , A Schiebahn , S Galka
The simulation of production systems in the planning phase is an established tool for evaluating system performance under dynamic conditions (Da Silva et al., 2018). When planning a production system that includes time-critical processes such as adhesive bonding, exceeding time constraints (e.g., excessive lead times relative to the adhesive pot-life) can lead to product rejection and scrap. These risks should be analyzed by means of simulation, as it enables the consideration of stochastic effects such as random machine breakdowns, which significantly influence product lead times.
This study focuses on the production of adhesively bonded electrolyzer-cells. Due to the cell design, several handling and stacking operations must be carried out between adhesive application and final joining, so that immediate joining is not feasible and pot-life-induced scrap becomes a critical risk factor. We therefore conducted an exploratory investigation that combines experimental pot-life characterization with discrete-event simulation of a planned electrolyzer-cell production system.
A two-component epoxy adhesive was characterized using differential scanning calorimetry with kinetic analysis, rotational rheometry, and 90° peel tests on application-representative joints. Based on these tests, an application-specific pot-life was derived and implemented as a time-dependent quality criterion in the discrete-event simulation model. A full-factorial simulation study with varied buffer size and mean time to repair at a station availability of 98 % was carried out. The results demonstrated a pronounced trade-off between throughput and pot-life-induced waste and identified a buffer capacity of one and short repair times as the most favorable configuration. Extending pot-life due to different processing temperatures substantially reduced scrap, highlighting the benefit of integrating curing kinetics and dynamic simulation in early-stage production system design for time-critical adhesive processes.
{"title":"Factory simulation of adhesive bonding processes considering pot-life-induced waste","authors":"V Ginster , A Weigert , MK Heym , CJA Beier , A Schiebahn , S Galka","doi":"10.1016/j.jajp.2026.100375","DOIUrl":"10.1016/j.jajp.2026.100375","url":null,"abstract":"<div><div>The simulation of production systems in the planning phase is an established tool for evaluating system performance under dynamic conditions (<span><span>Da Silva et al., 2018</span></span>). When planning a production system that includes time-critical processes such as adhesive bonding, exceeding time constraints (e.g., excessive lead times relative to the adhesive pot-life) can lead to product rejection and scrap. These risks should be analyzed by means of simulation, as it enables the consideration of stochastic effects such as random machine breakdowns, which significantly influence product lead times.</div><div>This study focuses on the production of adhesively bonded electrolyzer-cells. Due to the cell design, several handling and stacking operations must be carried out between adhesive application and final joining, so that immediate joining is not feasible and pot-life-induced scrap becomes a critical risk factor. We therefore conducted an exploratory investigation that combines experimental pot-life characterization with discrete-event simulation of a planned electrolyzer-cell production system.</div><div>A two-component epoxy adhesive was characterized using differential scanning calorimetry with kinetic analysis, rotational rheometry, and 90° peel tests on application-representative joints. Based on these tests, an application-specific pot-life was derived and implemented as a time-dependent quality criterion in the discrete-event simulation model. A full-factorial simulation study with varied buffer size and mean time to repair at a station availability of 98 % was carried out. The results demonstrated a pronounced trade-off between throughput and pot-life-induced waste and identified a buffer capacity of one and short repair times as the most favorable configuration. Extending pot-life due to different processing temperatures substantially reduced scrap, highlighting the benefit of integrating curing kinetics and dynamic simulation in early-stage production system design for time-critical adhesive processes.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100375"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-30DOI: 10.1016/j.jajp.2026.100378
H. Gruhn , A. Rajic , T. Krueger , M. Mund , M.W. Kandula
In battery cell production, electrodes are manufactured by coating current collectors with an active‐material slurry. Upon drying, this forms a porous composite of active material, conductive additives, and binder. The mechanical integrity of this coating is critical for electrode quality and subsequent processability. To assess these properties, pull-off tests and peel tests are commonly employed. While frequently categorized as “adhesion tests,” this label can be misleading; the fracture surfaces in these porous composites are rarely purely adhesive, yet a critical analysis of the specific fracture patterns is often neglected.
This study evaluates and compares the qualitative fracture patterns and quantitative results of both methods. To assess the sensitivity of each test, electrode properties were systematically varied by altering electrode thickness, binder type, and applying different calendering parameters. Results indicate that pull-off tests yield significant scatter due to undefined, multiaxial stress distributions, leading to inhomogeneous fracture patterns. In contrast, peel tests demonstrate minimal scatter with well‐defined crack propagation in a single plane, allowing for the detection of slight deviations in mechanical properties. Notably, the two methods reveal diverging trends regarding the impact of electrode thickness and calendering. Consequently, data from these methods are strictly incommensurable due to their fundamental mechanical difference.
{"title":"Mechanical testing of battery electrodes by pull-off and peel tests: A comparative study","authors":"H. Gruhn , A. Rajic , T. Krueger , M. Mund , M.W. Kandula","doi":"10.1016/j.jajp.2026.100378","DOIUrl":"10.1016/j.jajp.2026.100378","url":null,"abstract":"<div><div>In battery cell production, electrodes are manufactured by coating current collectors with an active‐material slurry. Upon drying, this forms a porous composite of active material, conductive additives, and binder. The mechanical integrity of this coating is critical for electrode quality and subsequent processability. To assess these properties, pull-off tests and peel tests are commonly employed. While frequently categorized as “adhesion tests,” this label can be misleading; the fracture surfaces in these porous composites are rarely purely adhesive, yet a critical analysis of the specific fracture patterns is often neglected.</div><div>This study evaluates and compares the qualitative fracture patterns and quantitative results of both methods. To assess the sensitivity of each test, electrode properties were systematically varied by altering electrode thickness, binder type, and applying different calendering parameters. Results indicate that pull-off tests yield significant scatter due to undefined, multiaxial stress distributions, leading to inhomogeneous fracture patterns. In contrast, peel tests demonstrate minimal scatter with well‐defined crack propagation in a single plane, allowing for the detection of slight deviations in mechanical properties. Notably, the two methods reveal diverging trends regarding the impact of electrode thickness and calendering. Consequently, data from these methods are strictly incommensurable due to their fundamental mechanical difference.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100378"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-12-23DOI: 10.1016/j.jajp.2025.100369
Abdelghani Laachachi , Oussema Kachouri , Julian Berndt , Gregor Zucker , Camilo Zopp , Jens Bartelt , Ahmed Makradi
A heat triggered debonding-on-demand thermoset-based adhesive is developed to join the glass fiber reinforced thermoplastic polyamide-6 to aluminium alloy sheet. The hybrid composite interface debonding mechanism is heat triggered at the end-of-life of the hybrid composite toward recycling of its components. The debonding-on-demand adhesive joint consist of an ARALDITE® brittle thermoset variant functionalized with 10% Expandable Graphite. TGA analysis and shear lab test are conducted to evaluate the effect of the Expandable Graphite on the degradation and mechanical performances of the ARALDITE® resin. Once validated the developed debonding-on-demand solution is up-scaled to a U-shape part made on inverse hybrid laminates.
{"title":"Use of expandable graphite as debonding on demand technology between glass fibre reinforced polyamide 6 and aluminium","authors":"Abdelghani Laachachi , Oussema Kachouri , Julian Berndt , Gregor Zucker , Camilo Zopp , Jens Bartelt , Ahmed Makradi","doi":"10.1016/j.jajp.2025.100369","DOIUrl":"10.1016/j.jajp.2025.100369","url":null,"abstract":"<div><div>A heat triggered debonding-on-demand thermoset-based adhesive is developed to join the glass fiber reinforced thermoplastic polyamide-6 to aluminium alloy sheet. The hybrid composite interface debonding mechanism is heat triggered at the end-of-life of the hybrid composite toward recycling of its components. The debonding-on-demand adhesive joint consist of an ARALDITE® brittle thermoset variant functionalized with 10% Expandable Graphite. TGA analysis and shear lab test are conducted to evaluate the effect of the Expandable Graphite on the degradation and mechanical performances of the ARALDITE® resin. Once validated the developed debonding-on-demand solution is up-scaled to a U-shape part made on inverse hybrid laminates.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100369"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-02-06DOI: 10.1016/j.jajp.2026.100381
Hana Šebestová , Jan Novotný , Jan Štěpán , Ondřej Ambrož , Zdeněk Joska , Jan Gross , Libor Mrňa
The deposition of functional cladding layers is a widely adopted technique to enhance the surface performance of engineering components without compromising their bulk material properties. Among the available techniques, wire arc cladding offers high productivity and is particularly effective for depositing relatively thick coatings. Thanks to its high hardness and reasonable toughness, Stellite 6 alloy is well-suited for wear-resistant claddings; however, its application through various welding processes is often accompanied by cracking. In this study, we propose and experimentally investigate a novel approach to wire arc cladding of this Co-based alloy that integrates localized in-situ heat treatment using a defocused oscillating laser beam. The laser-assisted process produced continuous and more uniform cladding layers. Compared to conventional wire arc cladding, the cooling rate decreased by 40 %, resulting in improved bead homogenization and fewer welding voids, while maintaining comparable microhardness after two passes. Enhanced bead fusion, facilitated by the laser, enabled very high deposition speed without compromising the structural integrity of the claddings.
{"title":"Laser-modified wire arc cladding","authors":"Hana Šebestová , Jan Novotný , Jan Štěpán , Ondřej Ambrož , Zdeněk Joska , Jan Gross , Libor Mrňa","doi":"10.1016/j.jajp.2026.100381","DOIUrl":"10.1016/j.jajp.2026.100381","url":null,"abstract":"<div><div>The deposition of functional cladding layers is a widely adopted technique to enhance the surface performance of engineering components without compromising their bulk material properties. Among the available techniques, wire arc cladding offers high productivity and is particularly effective for depositing relatively thick coatings. Thanks to its high hardness and reasonable toughness, Stellite 6 alloy is well-suited for wear-resistant claddings; however, its application through various welding processes is often accompanied by cracking. In this study, we propose and experimentally investigate a novel approach to wire arc cladding of this Co-based alloy that integrates localized in-situ heat treatment using a defocused oscillating laser beam. The laser-assisted process produced continuous and more uniform cladding layers. Compared to conventional wire arc cladding, the cooling rate decreased by 40 %, resulting in improved bead homogenization and fewer welding voids, while maintaining comparable microhardness after two passes. Enhanced bead fusion, facilitated by the laser, enabled very high deposition speed without compromising the structural integrity of the claddings.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100381"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-11-05DOI: 10.1016/j.jajp.2025.100357
Amin Shafinejad Bejandi, Hamid Khorsand, Mehdi Moslemi, Ali Ostad Akbarian Azar
Integrating tungsten carbide (WC–8Co) with steel is a pivotal aspect of cutting tool manufacturing, as monolithic carbide tools are inherently brittle and cannot be fabricated as a single component. To enhance toughness and resistance to dynamic stresses, WC is brazed to steels with greater ductility. Given WC's high melting temperature, conventional welding methods are ineffective, making brazing one of the most suitable techniques for joining dissimilar materials. This study aimed to optimize the brazing process to minimize the loss of WC hardness, as a reduction in hardness compromises tool efficiency and lifespan. In this research, WC–8Co was brazed to AISI 1006 steel using a silver-based filler (BAg22) through tube, induction, and infrared furnaces at temperatures of 800 °C, 850 °C, and 900 °C under vacuum conditions, with induction powers set at 10 and 15 kW. The microstructural and mechanical properties were assessed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), microhardness testing, and shear testing. The initial hardness of WC was measured at 2202 HV, with decreases of 1.8%, 10%, and 22% observed for the induction, infrared, and tube furnaces, respectively. The shear strength was highest for the induction furnace (294 MPa), followed by the infrared furnace (268 MPa) and the tube furnace (202 MPa). OM/SEM/EDS analyses revealed a silver- and copper-rich eutectic structure, while elevated temperatures enhanced filler wettability and diffusion, resulting in uniform, defect-free joints. These findings yield quantitative insights for optimizing the brazing of WC–steel joints, facilitating the manufacturing of high-performance cutting tools.
{"title":"Investigation of microstructural and mechanical properties of dissimilar WC–8 %Co/AISI 1006 steel joints brazed using tube, induction, and infrared furnaces","authors":"Amin Shafinejad Bejandi, Hamid Khorsand, Mehdi Moslemi, Ali Ostad Akbarian Azar","doi":"10.1016/j.jajp.2025.100357","DOIUrl":"10.1016/j.jajp.2025.100357","url":null,"abstract":"<div><div>Integrating tungsten carbide (WC–8Co) with steel is a pivotal aspect of cutting tool manufacturing, as monolithic carbide tools are inherently brittle and cannot be fabricated as a single component. To enhance toughness and resistance to dynamic stresses, WC is brazed to steels with greater ductility. Given WC's high melting temperature, conventional welding methods are ineffective, making brazing one of the most suitable techniques for joining dissimilar materials. This study aimed to optimize the brazing process to minimize the loss of WC hardness, as a reduction in hardness compromises tool efficiency and lifespan. In this research, WC–8Co was brazed to AISI 1006 steel using a silver-based filler (BAg22) through tube, induction, and infrared furnaces at temperatures of 800 °C, 850 °C, and 900 °C under vacuum conditions, with induction powers set at 10 and 15 kW. The microstructural and mechanical properties were assessed using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), microhardness testing, and shear testing. The initial hardness of WC was measured at 2202 HV, with decreases of 1.8%, 10%, and 22% observed for the induction, infrared, and tube furnaces, respectively. The shear strength was highest for the induction furnace (294 MPa), followed by the infrared furnace (268 MPa) and the tube furnace (202 MPa). OM/SEM/EDS analyses revealed a silver- and copper-rich eutectic structure, while elevated temperatures enhanced filler wettability and diffusion, resulting in uniform, defect-free joints. These findings yield quantitative insights for optimizing the brazing of WC–steel joints, facilitating the manufacturing of high-performance cutting tools.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100357"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145738199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polyvinyl chloride (PVC) forming operations are typified by large deformations, free-surface condition, complex conjugate heat transfer, and intricate contact phenomena. This study focuses on numerical modelling of the forming process that occurs beneath the butt-joint welding of polymeric profiles to offer a comprehensive understanding of how process parameters and boundary conditions influence the final weld. Numerical simulations are based on arbitrary and coupled Lagrangian and Eulerian models, which incorporate viscoelasticity, heat transfer, external forces, and free-surface flow. Due to the extensive temperature range encountered during the process, during heating the material transitions from a linear elastic state to a low-viscosity fluid. Consequently, the model has been developed to simultaneously solve for both solid and free-surface fluid conditions, and PVC has been modelled as a temperature-dependent viscoelastic solid, exhibiting Newtonian-like fluid characteristics under high temperatures. The proposed numerical solution methodology is employed to offer insights into the physics of the butt-welding process, widely utilised within industry. Two distinct configurations have been modelled to study material flow during the process: with and without a rigid constrain that prevents the material from moving freely upwards. These simulations aim to illuminate the impact of boundary conditions and physical constraints on the welding process and material behaviour.
{"title":"Butt-joint welding process of PVC Profiles: Numerical modelling, experimental validation and insights into material behaviour and flow dynamics","authors":"Riccardo Panciroli , Daniele Chiappini , Roberto Palazzetti","doi":"10.1016/j.jajp.2026.100374","DOIUrl":"10.1016/j.jajp.2026.100374","url":null,"abstract":"<div><div>Polyvinyl chloride (PVC) forming operations are typified by large deformations, free-surface condition, complex conjugate heat transfer, and intricate contact phenomena. This study focuses on numerical modelling of the forming process that occurs beneath the butt-joint welding of polymeric profiles to offer a comprehensive understanding of how process parameters and boundary conditions influence the final weld. Numerical simulations are based on arbitrary and coupled Lagrangian and Eulerian models, which incorporate viscoelasticity, heat transfer, external forces, and free-surface flow. Due to the extensive temperature range encountered during the process, during heating the material transitions from a linear elastic state to a low-viscosity fluid. Consequently, the model has been developed to simultaneously solve for both solid and free-surface fluid conditions, and PVC has been modelled as a temperature-dependent viscoelastic solid, exhibiting Newtonian-like fluid characteristics under high temperatures. The proposed numerical solution methodology is employed to offer insights into the physics of the butt-welding process, widely utilised within industry. Two distinct configurations have been modelled to study material flow during the process: with and without a rigid constrain that prevents the material from moving freely upwards. These simulations aim to illuminate the impact of boundary conditions and physical constraints on the welding process and material behaviour.</div></div>","PeriodicalId":34313,"journal":{"name":"Journal of Advanced Joining Processes","volume":"13 ","pages":"Article 100374"},"PeriodicalIF":4.0,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145925870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-11-29DOI: 10.1016/j.jajp.2025.100366
Johannes Wahl , Christian Frey , John Powell , Michael Haas , Simon Olschok , Uwe Reisgen , Christian Hagenlocher , Thomas Graf
During deep-penetration laser welding, a hot vapor plume is emitted from the keyhole which, on cooling, condenses into a particle cloud that surrounds the weld zone. This vapor plume and associated particle cloud interact with the incident laser beam through scattering, absorption, and phase front distortion, dynamically altering the beam caustic and potentially affecting weld quality. In this study, the mechanisms governing the beam-plume interaction are investigated by observation of the thermal emission and scattered laser light from the interaction zone during the welding of stainless steel, aluminum, and copper. For this analysis, a spectrometer and a high-speed camera equipped with optical filters were used. The results revealed significant material-specific differences in thermal emission and scattered laser light from the plume, indicating variations in absorption and scattering behavior and thus beam attenuation. Re-heating of plume material until evaporation took place for all three materials. Stainless steel exhibited the strongest thermal emission, while aluminum and copper showed significantly weaker emission. In contrast, the aluminum plume displayed the highest level of laser light scattering. This is attributed to the presence of liquid and solid particles rather than purely vaporized material, even close to the laser beam focus. Distinct interaction zones within the laser beam caustic were identified, each corresponding to specific aggregate states and characteristic laser-plume interactions. For stainless steel and copper, a zone forms close to the keyhole which is primarily composed of vaporized material. Beyond this there is a multi-phase zone containing both vapor and liquid or solid matter. Further from the keyhole, a particle zone with no detectable vapor appears as re-heating becomes insufficient for evaporation. In aluminum, no distinct vapor zone was detected. Instead, strong scattering near the keyhole indicates the presence of particles even at high laser intensities. Thus, only a multi-phase and a particle zone appear to form for aluminum under the welding parameters used.
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Pub Date : 2026-06-01Epub Date: 2025-12-26DOI: 10.1016/j.jajp.2025.100371
J.E. Tapia Cabrera, F. Groschupp, F. Riegger, M.F. Zaeh
The high flexibility of additive manufacturing (AM) enables the repair of components with complex geometries, contributing to the sustainability of the economy by reducing waste and increasing product lifetime. Wire arc additive manufacturing (WAAM) is well-suited for repair due to the high deposition rates compared to other AM technologies. Moreover, the automation potential of WAAM offers a promising opportunity for increasing productivity. However, the automated repair presents new challenges for quality assurance. During the deposition of successive layers, defects, such as a lack of fusion between adjacent weld beads, may be concealed within the parts. Due to their impact on the mechanical properties, such discontinuities constitute non-conformities and require part rejection. Therefore, a real-time monitoring system is required to detect lack of fusion defects and to ensure the reliable performance of the repaired components. Weld pool imaging provides detailed insights into process anomalies. Nonetheless, the harsh welding environment degrades the data quality and requires advanced imaging algorithms to extract features for a reliable analysis. The artificial intelligence (AI) architecture “You Only Look Once” (YOLO) allows for a robust detection performance and real-time capability with its one-stage approach for object detection. In this work, a monitoring system using two sequentially coupled YOLO-based models was developed. First, a detection model identifies the lack of fusion defects within the weld pool images, producing bounding boxes around the detected areas. These bounding boxes are then used as an input for a segmentation model, which provides a more precise delineation of the defects within the identified regions. The models were evaluated on unseen data, achieving a recall of over 90 % while maintaining real-time capability. This result showed the high potential of AI-based monitoring systems for real-time defect detection in WAAM to ensure the quality of the repaired components.
增材制造（AM）的高灵活性使具有复杂几何形状的部件得以修复，通过减少浪费和延长产品寿命，为经济的可持续性做出贡献。由于与其他增材制造技术相比，电弧增材制造（WAAM）具有较高的沉积速率，因此非常适合修复。此外，WAAM的自动化潜力为提高生产力提供了一个有希望的机会。然而，自动化维修对质量保证提出了新的挑战。在连续层的沉积过程中，缺陷，如相邻焊珠之间缺乏熔合，可能隐藏在零件内部。由于它们对机械性能的影响，这种不连续性构成不合格，需要零件报废。因此，需要一个实时监测系统来检测融合缺陷的缺失，并保证被修复部件的可靠性能。焊接池成像提供了对工艺异常的详细见解。然而，恶劣的焊接环境会降低数据质量，需要先进的成像算法来提取特征以进行可靠的分析。人工智能（AI）架构“You Only Look Once”（YOLO）采用单阶段对象检测方法，具有强大的检测性能和实时能力。在这项工作中，开发了一个使用两个顺序耦合的基于yolo的模型的监测系统。首先，检测模型识别焊池图像中缺乏融合缺陷，在检测区域周围产生边界框。然后将这些边界框用作分割模型的输入，该模型提供了对已识别区域内缺陷的更精确的描述。这些模型在未见过的数据上进行了评估，在保持实时能力的同时，实现了超过90%的召回。这一结果显示了基于人工智能的监测系统在WAAM中用于实时缺陷检测以确保被修复部件的质量的巨大潜力。
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