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Laser joining of titanium alloy to polyamide: influence of process parameters on the joint strength and quality
摘要： Laser-assisted metal–polymer joining (LAMP) is a novel assembly process for the development of miniaturized joints in hybrid lightweight products. This work adopts a design of experiments (DoE) approach to investigate the influence of several laser welding parameters on the strength and quality of titanium alloy (Ti-6Al-4V)–polyamide (PA6.6) assembly. Significant parameters were highlighted using the Plackett Burmann design, and process window was outlined using the Response Surface Method (RSM). A statistically reliable mathematical model was generated to describe the relation between highlighted welding parameters and joint strength. The analysis of variance (ANOVA) method was implemented to identify significant parametric interactions. Results show the prominence of focal position and laser power, as well as significant interaction between laser power and beam speed, on the joint strength. The evolution of weld defects (bubbles, excessive penetration, flashing, titanium coloring, weld pool cavities, and welding-induced deflection) along the process window was investigated using optical microscopy. The resulted deflection in titanium was quantified, and its relationship with welding parameters was mathematically modeled. Robust process window was outlined to maintain insignificant deflection in the welded joints. Results showed that the growth of weld defects correlates with a decline in joint strength. Optimal parameters demonstrated a defect-free joint, maximizing joint strength.
关键词： Hybrid joining,Metal–polymer assemblies,Laser beam joining,Process optimization
更新于2025-09-23 15:19:57
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Laser Induced Backward Transfer of ultra-thin metal structures
摘要： Ultra-thin, flexible and stretchable interfaces comprising thin metal films and polymers are attracting increasing interest for applications in sensors and optoelectronics. The transfer of ultra-thin gold films for the digital fabrication of such interfaces was investigated in this study using the Laser-Induced Backward Transfer (LIBT) technique. In particular, the transfer of thin and ultra-thin gold films (60, 10 and 5 nm thick) on Polydimethylosiloxane substrate has been achieved using ps pulses and low laser fluences for controllable material transfer. As the size of the nanograins comprising the Au films decreases, their melting point also decreases, enabling the transfer of intact disk-shaped Au nanostructures at low laser fluence values, with form factors and thickness equal to the pristine films. Moreover, the contribution of the substrate has been clarified: the two substrates (silicon, glass) which were used in this work, have significantly different reflectivity to the selected laser wavelength (532 nm), which can considerably influence the thickness and the quality of the transferred disk. The results presented in this work clearly demonstrate the compatibility of LIBT with ultra-thin metal film/ polymer interfaces and highlight the potential application of this digital process for a variety of optoelectronic applications.
关键词： ultra-thin films,Laser Induced Backward Transfer,metal/ polymer interface,short pulsed heating,nanostructures
更新于2025-09-23 15:19:57
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MECHANICAL AND OPTICAL INVESTIGATION OF LASER WELDED STRUCTURAL STEEL - POLY(METHYL-METHACRYLATE) HYBRID JOINT STRUCTURES
摘要： Modern welding processes that can easily be automated (such as friction stir welding, laser welding and ultrasonic welding) are gaining popularity in joining metal-polymer hybrid structures. This ?eld of science is intensively studied around the globe, as a dependable, productive joining method that directly produces structurally sound joints between a metal and a polymer structure could unleash unforeseen possibilities in the vehicle industry. In our experiments, we manufactured hybrid steel-poly(methyl-methacrylate) (PMMA) joints with laser welding, using the 2p design of experiment method. We measured the e?ect of cellulose reinforcing ?bres (in varying weight percentages) on the transparency and weldability of the PMMA material and the e?ect of welding parameters on the mechanical properties of the joints. We also examined the vicinity of the welded seam with scanning electron microscopy.
关键词： Laser welding,poly(methyl-methacrylate),metal-polymer hybrid structures
更新于2025-09-23 15:19:57
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Metal Polymer Connections: Laser-Induced Surface Enlargement Increases Joint Strength
摘要： The trend towards hybrid materials consisting of metals and polymers is strongly driven by requirements such as weight reduction and improved functionality. A crucial step towards new hybrid materials is the advancement of joining technology. While metals and polymers are currently often joined using adhesives, this technology has major drawbacks such as long process cycle time, low robustness with regard to changes of the material composition, and are almost impossible to recycle, a point which is becoming increasingly important. A promising joining method is thermal direct joining of metals and thermoplastic polymers due to its fast cycle time, its robustness of the process and the absence of duroplastic adhesives. Direct joining requires surface treatment of the metallic joining partner prior to the thermal joining process to achieve a sufficiently high contact strength. It is known that laser-induced topologies on the metal surface are beneficial with regard to contact strength of the joints. Designing a joint based on laser structured metals requires a fundamental understanding of the interface interactions. The present paper focuses on the influence of surface enlargement on the joint strength. Laser pretreatment was utilized to generate surface structures with specific surface enlargement on the metallic joining partner. The pretreated metallic parts were subsequently joined with a thermoplastic polymer by injection molding. The joint strength was investigated in single lap shear tests. The key finding is that the contact strength increases almost linearly with the surface area within the tested parameter range, while the structure geometry parameters have only a minor influence. This may help as a design guideline for future adhesive-free hybrid material joining technologies.
关键词： hybrid joining,laser material processing,metal polymer connection,micro structuring,metal polymer joints,lightweight,adhesion,in-mold assembly
更新于2025-09-16 10:30:52
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Laser Dissimilar Joining of Al7075T6 with Glass-Fiber-Reinforced Polyamide Composite
摘要： Dissimilar joining between metal and composite sheets is usually carried out by mechanical or adhesive joining. Laser dissimilar joining between metal and composite sheets could be an alternative to these methods, as it is a cost-effective and versatile joining technique. Previously, textured metallic and composite parts have been held together and heated with a laser beam while pressure is applied to allow the melted polymer to flow into the cavities of the metal part. The main issue of this process relates to reaching the same joint strength repetitively with appropriate process parameters. In this work, both initial texturing and laser joining parameters are studied for Al 7075-T6 and glass-fiber-reinforced PA6 composite. A groove-based geometry was studied in terms of depth-to-width aspect ratio to find an optimal surface using a nanosecond fiber laser for texturing. Laser joining parameters were also studied with different combinations of surface temperature, heating strategy, pressure, and laser feed rate. The results are relatively good for grooves with aspect ratios from 0.94 to 4.15, with the widths of the grooves being the most critical factor. In terms of joining parameters, surface reference temperature was found to be the most influential parameter. Underheating does not allow correct material flow in textured cavities, while overheating also causes high dispersion in the resulting shear strength. When optimal parameters are applied using correct textures, shear strength values over 26 kN are reached, with a contact area of 35 × 45 mm2.
关键词： metal polymer joint,groove aspect ratio,laser structuring,laser direct joining,shear strength
更新于2025-09-16 10:30:52
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Aluminum pretreatment by a laser ablation process: influence of processing parameters on the joint strength of laser welded aluminum – polyamide assemblies
摘要： Laser welding of metal – polymer assemblies is an innovative bonding process. It was already demonstrated that laser surface pretreatments of aluminum (Al), prior to laser welding with a polymer, impacts joints strength. This work adopts a design of experiments (DoE) approach to investigate the influence of several Al laser ablation parameters on joint strength of laser welded Al – polyamide (PA6.6) assemblies. Significant parameters were highlighted, process window was outlined, and optimal parameters were identified. After assembly failure, the joint area was evaluated using optical microscopy. Depending on the laser ablation parameters, the joint area can be enhanced resulting in a significant increase in the corresponding bearable shear load.
关键词： Metal-polymer assemblies,Laser ablation,Laser beam welding,Hybrid joining
更新于2025-09-12 10:27:22
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Influence of Aluminum Laser Ablation on Interfacial Thermal Transfer and Joint Quality of Laser Welded Aluminum–Polyamide Assemblies
摘要： Laser assisted metal–polymer joining (LAMP) is a novel assembly process for the development of hybrid lightweight products with customized properties. It was already demonstrated that laser ablation of aluminum alloy Al1050 (Al) prior to joining with polyamide 6.6 (PA) has significant influence on the joint quality, manifested in the joint area. However, profound understanding of the factors affecting the joint quality was missing. This work investigates the effects of laser ablation on the surface properties of Al, discusses their corresponding impact on the interfacial thermal transfer between the joining partners, and evaluates their effects on the joint quality. Samples ablated with different parameters, resulting in a range from low- to high-quality joints, were selected, and their surface properties were analyzed by using 2D profilometry, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX). In order to analyze the effects of laser ablation parameters on the interfacial thermal transfer between metal and polymer, a model two-layered system was analyzed, using laser flash analysis (LFA), and the thermal contact resistance (TCR) was quantified. Results indicate a strong influence of laser-ablation parameters on the surface structural and morphological properties, influencing the thermal transfer during the laser welding process, thus affecting the joint quality and its resistance to shear load.
关键词： laser ablation,laser welding,metal–polymer,thermal contact resistance
更新于2025-09-11 14:15:04