Insights into Ultrasonic Welding of ABS-PC (Mycril) Polymers: Characterization and Performance Analysis

The analysis of MIG welding performance and welding deformation control of medium/high strength aluminum alloy plates is a hot topic of current research. By applying high-energy ultrasound during the MIG welding process to control the welding deformation and performance of welded joint of LC52 aluminum alloy plate, and comparing and analyzing it with the traditional MIG welded joint, the influence of high-energy ultrasound control process parameters on the welding residual stress distribution, welding deformation, mechanical properties, and microstructure of LC52 aluminum alloy welding test plate was mastered. The residual stress values and distribution state of high-energy ultrasonic welding compared with conventional welding were analyzed through the use of LCR wave stress detection method with conversion or broadband frequency. The microscopic grain structure of welded joint was studied by using metallographic optical microscopy, impact testing and tensile testing of welded joint were carried out and the fracture pattern of tensile specimens was observed by using scanning electron microscopy. The crystallization process of the welded joint was changed by injecting high-energy ultrasound in the MIG welding process, meanwhile, the process of weld solidification and heat transfer or diffusion based on the action of high-energy ultrasonic wave directly led to changes in the properties of the welded joint. The results showed that the welding residual stress was significantly reduced and homogenized in the MIG welding process of LC52 aluminum alloy plate based on certain timing constraints after the application of high-energy ultrasonic control. The average welding residual stress reduction rate and the stress homogenization rate of the plate under each detection depth reached more than 70.0% and 50.0%, respectively. The welding deformation was effectively controlled with reduction by 68.8%. In addition, the grain size and distribution state of microstructure in the weld zone, fusion and heat affected zone were refined and equalized by using this welding control process. Compared with the conventional welding method (i.e., not under regulation), the impact strength of the weld fusion and heat-affected zone under the action of high-energy ultrasonic waves were increased by 71.7% and 33.6%, respectively, and the tensile strength and elongation of the welded joint were increased by 24.0% and 46.7%, respectively, improving the fracture morphology of weld and then showing better mechanical properties. Therefore, the process of high-energy ultrasonic MIG welding was applied to control the welding deformation and improve the welding properties of LC52 aluminum alloy. The important support for improvement of the welding quality of aluminum alloy plate and even its stability and safety in service was provided by this study.

Ultrasonic metal welding is often used as a rapid and effective technique for joining sheet metals without causing them to melt. Precise management of the welding process parameters is crucial for achieving excellent joint quality. However, modeling the behavior of the weld material and the welding process is still very challenging. This study aimed to create 3D finite element models that accurately simulate the ultrasonic metal welding process. The proposed material model integrates frictional heat and ultrasonic softening, as well as the cyclic plasticity model. A friction law incorporating a variable friction coefficient is examined to investigate surface impacts. This coefficient is influenced by contact pressure, slippage, temperature, and the number of cycles. The findings of this study demonstrate that the oscillation frequency significantly influences both the temperature fluctuation and the extent of the heat-affected zone. Increased frequencies lead to accelerated temperature fluctuations and expanded heat-affected. Furthermore, ultrasonic welding combined with preheating led to a much wider heat-affected zone than ultrasonic welding without heating. The minimum preheating temperature required for ultrasonic welding of aluminum is 150 °C. This model can predict the relative displacement between welded plates. Assessing the oscillations that arise during the ultrasonic welding process is beneficial in selecting suitable welding settings to prevent excessive heating. This aids engineers in choosing appropriate welding parameters to avoid excessive heat generation during ultrasonic welding, hence limiting the reduction in tensile strength of the weld. Consequently, it can decrease the expense of the experimental methodology.

Ultrasonic Welding of Metal Sheets covers various aspects of ultrasonic welding (USW) of metal sheets, including the discussion on modeling and numerical simulations of ultrasonic welding to improve this welding process and performance. This book aims to provide an accessible, comprehensive and up-to-date exposition of the various aspects of joining of dissimilar metal sheets ranging from its fundamentals thorough to metallurgical characteristics covering fundamental concepts, in-detailed explanation about the USW including its implementation, design criteria, work material, welding, thermo-mechanical and research scopes. The book is aimed at researchers, professionals and graduate students in manufacturing, welding, mechanical engineering. Features The ultrasonic spot welding of various metal sheets is described in simplified expression and concepts are elucidated by relevant illustrations. Discusses modeling and numerical simulations of ultrasonic welding to improve the ultrasonic welding process and performance As opposed to competition in the market, this title provides thorough clarification of ultrasonic spot welding of metal sheets with its applications.

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining such as welding to meet desired power and capacity needs. However, conventional fusion welding processes such as resistance spot welding and laser welding face difficulties in joining multiple sheets of highly conductive, dissimilar materials with large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining, such as welding, to meet the desired power and capacity needs. However, conventional fusion welding processes, such as resistance spot welding and laser welding, face difficulties in joining multiple sheets of highly conductive, dissimilar materials to create large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time using copper-to-copper welding as an example. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.

Process physics understanding, real time monitoring, and control of various manufacturing processes, such as battery manufacturing, are crucial for product quality assurance. While ultrasonic welding has been used for joining batteries in electric vehicles (EVs), the welding physics, and process attributes, such as the heat generation and heat flow during the joining process, is still not well understood leading to time-consuming trial-and-error based process optimization. This study is to investigate thermal phenomena (i.e., transient temperature and heat flux) by using micro thin-film thermocouples (TFTC) and thin-film thermopile (TFTP) arrays (referred to as microsensors in this paper) at the very vicinity of the ultrasonic welding spot during joining of three-layered battery tabs and Cu buss bars (i.e., battery interconnect) as in General Motors's (GM) Chevy Volt. Microsensors were first fabricated on the buss bars. A series of experiments were then conducted to investigate the dynamic heat generation during the welding process. Experimental results showed that TFTCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TFTPs were more sensitive to the transient heat generation process during welding than TFTCs. More significantly, the heat flux change rate was found to be able to provide better insight for the process. It provided evidence indicating that the ultrasonic welding process involves three distinct stages, i.e., friction heating, plastic work, and diffusion bonding stages. The heat flux change rate thus has significant potential to identify the in-situ welding quality, in the context of welding process monitoring, and control of ultrasonic welding process. The weld samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study the material interactions at the bonding interface as a function of weld time and have successfully validated the proposed three-stage welding theory.

In this research, dissimilar joint properties of pure Cu to AISI304 stainless steel using three different filler metals were studied. In this regard, the welding process was done with gas tungsten arc welding process using ER308L, ER309L, and ERNiCrMo3 filler metals and ERNi1 butter layer. The microstructural evaluations were carried out using optical microscope and scanning electron microscope. The mechanical tests were conducted by microhardness, tensile, bending and impact tests, and the fracture surfaces of impact and tensile tests were studied by scanning electron microscope. The results show that there is no crack or discontinuity in the welded samples. Energy-dispersive spectroscopy analysis revealed that the diffusion of Cu from base metal to butter layer has been occurred during welding. The microhardness profiles indicated the increase of hardness in heat-affected zone and butter layer. The welded sample with ERNiCrMo3 filler metal showed higher microhardness (200 HV) as compared with two other welded samples. The welded sample with ER309L filler metal had lower microhardness of about 150 HV. The tensile test revealed that the welded sample with ER309L filler metal showed maximum (193 MPa) and the welded sample with ER308L showed minimum (147 MPa) of ultimate tensile strength. In bending test of the welded samples with ER308L and ERNiCrMo3 filler metals, the crack and discontinuity were revealed in weld metal and heat-affected zone of Cu, respectively, while in the welded sample with ER309L filler metal no crack and discontinuity were seen. Also the welded sample with ER309L filler metal had highest impact energy of about 90 J as compared to other samples (81 and 88 J for the welded samples with ER308L and ERNiCrMo3 filler metals, respectively). The welded sample with ER309L filler metal showed more ductile fracture surface as compared with other samples.

Ultrasonic metal welding for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass and equivalent stiffness, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effects on weld quality, and thus provides useful guidelines for design and welding of battery tabs from tab dynamics point of view.

Ultrasonic metal welding (USMW) for battery tabs must be performed with 100% reliability in battery pack manufacturing as the failure of a single weld essentially results in a battery that is inoperative or cannot deliver the required power due to the electrical short caused by the failed weld. In ultrasonic metal welding processes, high-frequency ultrasonic energy is used to generate an oscillating shear force (sonotrode force) at the interface between a sonotrode and few metal sheets to produce solid-state bonds between the sheets clamped under a normal force. These forces, which influence the power needed to produce the weld and the weld quality, strongly depend on the mechanical and structural properties of the weld parts and fixtures in addition to various welding process parameters, such as weld frequencies and amplitudes. In this work, the effect of structural vibration of the battery tab on the required sonotrode force during ultrasonic welding is studied by applying a longitudinal vibration model for the battery tab. It is found that the sonotrode force is greatly influenced by the kinetic properties, quantified by the equivalent mass, equivalent stiffness, and equivalent viscous damping, of the battery tab and cell pouch interface. This study provides a fundamental understanding of battery tab dynamics during ultrasonic welding and its effect on weld quality, and thus provides a guideline for design and welding of battery tabs from tab dynamics point of view.

Ultrasonic welding (USW) is a fast and effective method for joining thermoplastic composites, offering excellent bonding strength that results in lightweight, durable structures, making it a cost-effective alternative to traditional joining techniques. The crystallinity at the weld interface impacts the mechanical properties and chemical resistance of the joint. The crystallization mechanisms at the bonded interface remain inadequately understood for the USW process, especially given its rapid cooling rates. This study investigates the use of polypropylene (PP) and multiwalled carbon nanotube (MWCNT)/PP films for ultrasonic welding of glass fiber (GF)/PP adherends, focusing on how process parameters influence the crystallinity degree, crystalline phases, crystallite size and spacing, lamellar structure and anisotropy, and molecular changes at the welded interface. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and small-angle X-ray scattering (SAXS) were employed to gain a better understanding of crystalline structure at the interface. Four different sets of welding force and amplitude were tested: (1) 500 N, 38.1 μm, (2) 500 N, 54.0 μm, (3) 1500 N, 38.1 μm, and (4) 1500 N, 54.0 μm. The study demonstrated that despite fast cooling rates obtained during the process, higher welding force and amplitude significantly enhanced crystallinity, achieving 55% for welds with pure PP films and approximately 60% for MWCNT/PP films, compared to 35% and 41%, respectively, before welding. Notably, amplitude influenced the crystallinity at the welded interface more significantly compared to the force. SAXS experiments revealed that both pure PP and MWCNT/PP films exhibited isotropic structures prior to welding, but distinct anisotropy after welding. These findings suggest that strain-induced crystallization results from the welding process, with the degree of anisotropy correlating with the applied welding force and amplitude.

Ultrasonic plastic welding is widely used in the bonding process of medical device accessories. In this paper, a thermo-force indirect coupling finite element analysis model was established in the ultrasonic plastic welding process between the blood cap and the shell of polypropylene (PP) dialyzer. The temperature field distribution between the blood cap and the shell was simulated and analyzed by using finite element analysis software, and the influence of welding process parameters on the temperature field was studied. The results show that: by changing the ultrasonic amplitude parameters, welding time parameters, initial pressure, etc., the longer the ultrasonic welding time, the temperature of the welding area will increase. In order to ensure the quality of the dialyzer, it should be controlled within 0.8-1 seconds. The increase of ultrasonic amplitude will make the welding temperature continue to rise, and in order to avoid poor welding, the amplitude should not exceed 120 ?m. The initial pressure has little effect on the temperature field.

Simulating microstructure evolution of battery tabs during ultrasonic welding

Investigation on waterproof mechanism and micro-structure of cement mortar incorporated with silicane

Ultrasonic welding (USW) is a rapid and efficient joining method for thermoplastic polymer composites. This joining technique offers a high bonding strength between composite materials to form lightweight, durable structures in a costeffective way, compared to other traditional joining methods. Crystallinity at the bond line can influence mechanical properties and chemical resistance. However, despite technological development of the USW process, the underlying crystallization mechanisms at the welded interface are still insufficiently understood. This paper explores the use of polypropylene (PP) and multifunctional multi-walled carbon nanotube (MWCNT/PP) films to perform USW between glass fiber (GF)/PP adherends and the resulting effect of welding parameters on the crystallinity degree at the bonded interface. After the USW process, PP and MWCNT films were isolated from glass fiber laminates using Kapton tapes. The effect of MWCNT content (0, 5, 10, 15, 20, 25 wt.%) and welding parameters on the crystallinity of the films and the welded interface was analyzed using differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM), respectively. It was found that increasing MWCNT percentage resulted in a lower degree of crystallinity (44-34%) for the films and for the welded composite interface (23-9%). Four sets of different parameters (welding force and vibration amplitude) were used in this experiment, (500N, 38.1μm), (500N, 54.0μm), (1500N, 38.1μm), and (1500N, 54.0μm), representing different welding times. It was found that increasing force and amplitude resulted in a higher and lower degree of crystallinity, respectively, at the welded interface. Thus, it is expected that the change of crystallinity during USW may be partially attributed to strain-induced crystallization mechanisms.

The extensive accumulation of plastic waste causes serious environmental problems, leading to growing interest in biodegradable alternatives. In this study, the structural, chemical, and crystalline characteristics of a pulp-based material incorporating sugarcane bagasse ash (SCBA) were investigated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties of the materials were investigated through compression, tensile, and bending tests in order to assess their strength and flexibility, while biodegradability was evaluated through soil burial tests. The results indicate that SCBA addition enhances compressive strength, with optimal performance obtained at 15% SCBA content, while tensile and bending strengths showed an enhancement at 5% content. FTIR and XRD analyses suggested an increase in amorphous regions and notable microstructural interactions between SCBA particles and cellulose fibers, particularly at a 10% concentration. SEM images further confirmed effective particle dispersion and improved porosity in the composite materials. Furthermore, samples incorporating SCBA exhibited superior biodegradability compared to pure pulp. Overall, these findings highlight that incorporating 10–15% SCBA provides a promising balance between mechanical integrity and environmental sustainability, offering a viable strategy for developing eco-friendly, high-performance packaging materials.