Ultrasonic Welding Parameters Research Articles

Impact of Ultrasonic Welding Parameters on Weldability and Sustainability of Solid Copper Wires with and without Varnish.

This article contains an advanced analysis of the properties of solid wire electrical contacts produced by ultrasonic welding, both with and without varnish. The main disadvantage of ultrasonic welding of thin wires is the inability to achieve acceptable peel force and tensile strength, which is mainly due to the deformation and thinning of the wires. This study deals with ultrasonic welding using a ring of thin solid copper wires that minimises the deformation and thinning of the wires. The influence of welding parameters such as energy, pressure and amplitude were systematically analysed. Based on these parameters, the optimum welding programme and control method was determined to weld unvarnished and varnished wires. The investigations included electrical resistance tests, optical microscopy, micro-hardness measurements, peel tests and tensile tests, and the measurement of energy consumption. The results showed no significant differences in microstructure and hardness between varnished and unvarnished joints. Ultrasonic joints of varnished wires achieved lower electrical conductivity (by 38%), lower tensile strength (by 3%) and higher peel strength (by 7%), while the welding process was more sustainable in terms of energy (by 6.6%) and time consumption (without preprocessing).

Orthogonal experiments and bonding analysis of ultrasonic welded multi-layer battery foils and tabs

The motivation for this research stems from the growing demand for solid-phase welding technology to join multilayers metals, particularly in green electric vehicles. Welding of foils and tabs inside battery is a challenging task due to poor joint formation at the interface and low strength. Ultrasonic welding is an efficient, reliable and environmentally friendly bonding method to firmly connect multi-layer copper foils and tabs. Therefore, this is used to achieve electrical bonding within the lithium-ion batteries. This is widely used in production of new energy vehicle batteries. In this work, 40 layers of copper foil were bonded to 0.3 mm nickel-plated copper tabs using ultrasonic metal welding technology. The effect of ultrasonic welding parameters on T-peel strength of joints was systematically investigated by orthogonal experimental design. The maximum T-peel strength of 359.17 N was obtained under optimal parameters (e.g., welding energy 600 J, pressure 0.3 MPa and amplitude 55 %). The variation of welding temperature and amplitude under different welding parameters was measured using infrared thermometer and laser vibrometer. Moreover, the surface, cross-sectional and failure fracture analysis and characterization of specimens with different weld qualities were performed using optical microscopy and scanning electron microscopy (SEM). In addition, the state of Ni layer in cross-section was analyzed using the energy dispersive spectroscopy (EDS) technique after ultrasonic welding. This approach can be straightforward and more appropriate to the development of solid-phase welding method for automotive industry.

Effect of the Energy Director Material on the Structure and Properties of Ultrasonic Welded Lap Joints of PEI Plates with CF Fabric/PEI Prepreg

To estimate the possibility of using both low-melting TecaPEI and neat PEI films as energy directors (EDs) for ultrasonic welding (USW) of carbon fiber (CF) fabric–polyetherimide (PEI) laminates, some patterns of structure formation and mechanical properties of their lap joints were investigated by varying the process parameters. The experiment was planned by the Taguchi method with the L9 orthogonal matrix. Based on the obtained results, USW parameters were optimized accounting for maintaining the structural integrity of the joined components and improving their functional characteristics. The use of the low-melting EDTecaPEI film enabled US-welding the laminates with minimal damage to the fusion zone, and the achieved lap shear strength (LSS) values of ~7.6 MPa were low. The use of EDSolverPEI excluded thermal degradation of the components as well as damage to the fusion zone, and improved LSS values to 21 MPa. With the use of digital image correlation (DIC) and computed tomography (CT) techniques, the structural factors affecting the deformation behavior of the USW lap joints were justified. A scheme was proposed that established the relationship between structural factors and the deformation response of the USW lap joints under static tension. The TecaPEI film can be used in USW procedures when very high interlayer adhesion properties are not on demand.

Microstructure evolution and mechanical properties analysis in dissimilar ultrasonic metal welding of aluminum to copper

Ultrasonic metal welding is a solid-state welding process being widely employed for joining the interconnections of lithium-ion batteries in hybrid and plug-in hybrid vehicles. Examining the microstructure of the joint is of crucial importance to evaluate the performance. This analysis allows a comprehensive understanding of the phenomena influencing the joint strength. In this study, ultrasonic welding was utilized to join copper to aluminum sheets of 0.3 mm thickness, and then the macro- and microstructural characteristics of the weld cross-section and interface were thoroughly investigated. Finally, the microstructural changes at different values of ultrasonic welding parameters were correlated with the mechanical strength characteristics. This research identified mechanical interlocking and interface diffusion as the primary welding mechanisms. With an increase in welding time from 0.2 to 0.8 s, the bond density rose, the post-weld thickness decreased, and the average Vickers hardness at various points along the weld interface decreased by 10%.

Optimization of ultrasonic welding parameters for better seam performance

PurposeUltrasonic welding is an emerging apparel manufacturing technique. However, the applications are widely explored in the field of technical textiles, with less exploration in the apparel endues. The purpose of this study is to explore the application of ultrasonic welding in apparel by analyzing the impacts of different parameters.Design/methodology/approachThis study analyzed the influence of ultrasonic welding parameters, including pressure, welding speed and ultrasonic power on the seam performances (seam strength, seam bursting strength, seam thickness and seam stiffness). The parameters are optimized using Box–Behnken experimental design to achieve better seam performances.FindingsThe properties of ultrasonic seams are influenced by welding and fabric properties. Ultrasonically welded seams showed better performances in the case of comfort properties of seams, whereas the functional properties are lesser compared to conventional seams.Originality/valueThe findings of the research clearly outline the level of influence of different parameters on the performance of the ultrasonically welded seams in knitted fabrics, which can greatly help in applying ultrasonic welding manufacturing methods in apparel manufacturing.

Determination of proper parameters for ultrasonic welding of copper plate with copper wire strands

Ultrasonic welding parameters originally provided by the components supplier caused negative pull/peel tension results. In this paper, we present a method to find the optimal parameters for the ultrasonic welding of copper elements. These elements represent components inside an electrical harness from automotive industry: coper plate and copper wire strands. The design of experiments (DoE) was used as a method within the Six Sigma approach. We succeeded in obtaining welding parameters that ensure successfully passing the pull/peel tension test.

Optimization of Ultrasonic Welding Parameters Based on Response Surface Methodology

In this paper, the optimal process parameters for ultrasonic welding of copper wire and aluminum plates are studied using the response surface method. The effect of various welding parameters on the welding effect is experimentally tested. The results are analyzed using the Box-Behnken design to establish a regression model to optimize the welding parameters. The model uses the welding height, welding energy and welding pressure as influencing factors and the welding strength and welding time as response values. The results show that optimal welding of copper wire and aluminum plate is obtained at the height of 2.2mm, energy 1300J, amplitude 85% or 95%. The response surface method used in this paper can provide a reference for the ultrasonic welding of other materials in the study of process parameters.

Optimization of ultrasonic welding parameters for laminate PEEK-based composites with carbon fiber prepreg

In this study, ranking of the key ultrasonic welding (USW) parameters for joining laminate composites was carried out using the Taguchi method. To understand the nature of the revealed effects, an analysis of the structure at the fusion zone interface was performed. In shear tests, fracture of the lap welded joints through the base material was associated not only with high shear stresses, but also with double macrobending of the samples because of the increased rigidity of their central parts, possessing twice thickness values. It was found that fracture of carbon fibers due to the prepreg melting was a negative factor. However, it could provide additional reinforcement of the material in the fusion zone upon the USW process, increasing shear strength. The porosity formation at the interface could be associated with melting of both Energy Director (ED) films and the prepreg, in addition to the joined plates from the PEEK-based composite. The prepreg melting inevitably resulted in fracture of reinforcing fibers. As a result of the study, the most rational mode was reported. Finally, it is proposed to use changes in thicknesses of the lap welded joints as one of the key parameters for controlling the USW process.

Optimizing Ultrasonic Welding Parameters for Multilayer Lap Joints of PEEK and Carbon Fibers by Neural Network Simulation.

The aim of this study is to substantiate the use machine learning methods to optimize a combination of ultrasonic welding (USW) parameters for manufacturing of multilayer lap joints consisting of two outer PEEK layers, a middle prepreg of unidirectional carbon fibers (CFs), and two energy directors (EDs) between them. As a result, a mathematical problem associated with determining the optimal combination of technological parameters was formulated for the formation of USW joints possessing improved functional properties. In addition, a methodology was proposed to analyze the mechanical properties of USW joints based on neural network simulation (NNS). Experiments were performed, and threshold values of the optimality conditions for the USW parameters were chosen. Accordingly, NNS was carried out to determine the parameter ranges, showing that the developed optimality condition was insufficient and required correction, taking into account other significant structural characteristics of the formed USW joints. The NNS study enabled specification of an extra area of USW parameters that were not previously considered optimal when designing the experiment. The NNS-predicted USW mode (P = 1.5 atm, t = 800 ms, and τ = 1500 ms) ensured formation of a lap joint with the required mechanical and structural properties (σUTS = 80.5 MPa, ε = 4.2 mm, A = 273 N·m, and Δh = 0.30 mm).

Application of artificial neural network models to predict ultrasonic welding parameters for joining copper to aluminium sheet

Ultrasonic welding is a method of combining solid-state components that does not require the use of heat or flux and instead relies on vibration to hold the components together. When connecting copper wires to an equipment alternator in electrical and automotive applications, a solid-state joining method is utilized as the preferred connection method. This situation calls for the utilization of ultrasonic welding of metal. In businesses that use ultrasonic metal welding processes, issues with weld quality and strength appear to be the most frequently encountered difficulties. These issues are frequently the result of inadequate parameter selection, which may be traced back to the welding process. To produce ultrasonically welded joints with a thickness of 0.3 mm, the welding characteristics of copper to aluminum connections, such as welding pressure, weld duration, and vibration amplitude, are considered in this study. Compared to the size of this weld, alternative joint construction methods could potentially cause damage to the joint. To conduct the tests, a suitable experimental design was conceived and put into action by employing Taguchi's robust design process in a manner that was tailored to the specifics of the situation. With the help of a synthetic neural network, the answer was predicted, and its accuracy was checked using the mean square relative error, the Nash-Sutcliffe efficiency, and the mean absolute percentage error.

Influence of welding parameters and surface preparation on thin copper–copper sheets welded by ultrasonic welding process

Ultrasonic welding is increasingly used in industry. In this paper, the influence of ultrasonic welding parameters (USW) on the joint strength and quality was analysed. The properties of the USW joints depend on many factors. The work focuses on the influence of the technological parameters and the surface properties of welded EN Cu-ETP copper sheets with a thickness of 1 mm. The impact of the process parameters, such as welding time, pressure, vibration amplitude and the surface roughness on the lap shear strength and the metallographic weld properties was analysed. The welding energy for each variant was also determined. The research was conducted on the basis of a full factorial design of experiments. The optimal process parameters were determined to obtain high-quality joints in terms of strength and weld quality. Based on the presented experimental study, it was demonstrated that the ultrasonic vibration amplitude has the greatest impact on the joint strength. A surface preparation with acetone resulted in the highest tensile strength and welding energy and, making any additional surface treatment prior to welding unnecessary.

Investigation of Actual Phenomena and Auxiliary Ultrasonic Welding Parameters on Seam Strength of PVC-Coated Hybrid Textiles

Abstract A study of polyvinylchloride-coated woven polyester fabric welding potential was conducted using continuous ultrasonic welding machines. The effect of cooling air, anvil wheel status, anvil wheel width, material surface contact, and welding gap on seam strength was studied. Three main welding parameters with different levels were selected based on 5 and 10 mm welding widths using old and new anvil wheels with and without cooling air. A lapped type of seam was applied under full factorial design. A microstructure was captured to examine the formation of welding joints, and seam tensile properties were determined. Comparative analysis of comparable welding parameters was analyzed for a gap against pressure and amplitude against power. The actual weld phenomenon was also analyzed based on the recorded machine parameters. The results showed that auxiliary parameters had a significant effect on seam strength. A microscopic image of a welded seam indicated that cooling air reduced the number and size of holes produced. Weld seam with controlled pressure or power provided higher seam strength than that of the controlled gap or amplitude. The actual phenomenon of welding parameters was important to evaluate weld seam quality, whereby the obtained results indicated good quality at lower power and pressure.

Orthogonal experiments and bonding analysis of ultrasonic welded multi-strand single core copper cables

The join demand for multi-strand single core copper cables in battery packs is increasing vigorously for new energy vehicles. In this paper, the influences of ultrasonic welding parameters on the microstructure, gap fraction and T-peel strength of the copper cable joints were studied systematically by orthogonal experiments. Under the optimum combination of parameters (welding time = 0.8 s, pressure = 4 bar, amplitude = 62.4 μm), a contact joint with low gap fraction of 2.07% was obtained and the maximum T-peel force reached 432.9 N. The T-peel fracture characterized by dimples indicates that metallurgical bonding was formed between copper wires, rather than simple mechanical interlock. Furthermore, the electron backscattered diffraction (EBSD) technology was used to analyze grain boundary types and texture evolution during ultrasonic welding. After ultrasonic welding, continuous 〈111〉 texture and lots of large angle grain boundaries (LAGBs) that composed of high-density dislocations and substructure were found in bonding interfaces of copper wires, which indicates that serious plastic deformation has occurred in bonding region. When interfacial temperature of cables joints provides enough energy for dislocations motion and rearrangement, the dislocations and substructure nucleate and grow into equiaxed grains through the process of copper recrystallization under high interfacial temperature, which promotes the formation of new interfaces between the copper wires.

Effect of ultrasonic welding process parameters on peel strength of membranes for tents

Ultrasonic welding is a universal, clean, and secure alternative joining method. Alternative joining technologies are used increasingly to fulfill specific functional requirements of the seam, such as fluid impermeability to achieve positive bonding during the assembly of technical textiles. In this research, the effect of important ultrasonic welding parameters on peel strength and weld seam thickness was investigated for flexible and lightweight textile material, which is a valuable innovative hybrid textile for technical applications like architectural, construction, and protective textiles. Three main welding parameters with three different levels were selected based on the preliminary test results of 6 and 12 mm welding widths, and a superimposed type of seam was applied. Light scanning microscopic images were used to examine the effective weld locations and their morphology at the joining interface. The parametric influence of ultrasonic welding technique on-seam quality and their tendencies in the relationship were analyzed. Optimized peel strength yielding parametric levels were also assessed numerically. The result shows that the optimal peel strength value was obtained at a welding speed of 2.318 m/min, power of 119.382 W, and pressure force of 349.729 N for a 12 mm welding width. The weld seam thickness had an inverse relationship with the peel strength, and a higher amount of thickness was reduced to 12 mm welding width than 6 mm. Microscopic cross-sectional image of weld seam indicated that a compressed yarn between the coating material at higher welding power and pressure force in lower welding speed. A nonlinear quadratic numerical model was developed to predict the peel strength, and their results were close to the regressed diagonal line against the actual points. The statistical analysis was carried out to show the significant effect of process parameters on peel strength, whereby the obtained results were statistically significant.

Producing a Dissimilar Joint of Copper to Austenitic Stainless Steel by Ultrasonic Welding

Abstract There are several possibilities for establishing a cohesion joint between dissimilar metals. In the case of thin sheets, the ultrasonic welding process is suitable. This process can establish a cohesion joint rapidly, with a low heat input between the thin sheets. The authors have tried to determine the optimal ultrasonic welding parameters for copper and austenite stainless steel joining by using an experimental method of joining. Suitable results were obtained by welding tests due dissimilarities in the chemical, physical and mechanical properties of the copper and stainless steel. A standard size sheet thickness and test sample was used for the welding by different parameters. The parameters were refined based on the theoretical and practical knowledge during the experiments. The experimental welding was made by a Branson L20 type welder machine. The joint made by the different parameters was inspected by shearing-tensile tests (maximal force level).

Effect of ultrasonic welding process parameters on hydrostatic pressure resistance of hybrid textiles for weather protection

In the research project presented in this paper, the effects of welding width, pressure force, power, and speed of ultrasonic welding parameters on hydrostatic pressure resistance were examined. A flexible and lightweight PVC-coated hybrid textile material with uniform thickness was used for weather protection purposes. Three main welding parameters at three different levels were selected based on the preliminary test results involving welding widths of 6 and 12 mm. A lapped type of seam was applied for ultrasonic welding and conventional joining techniques. A conventionally sewn zigzag seam was produced using three main factors at two different levels according to the application area. To avoid seam permeability, the conventional seam was sealed with tape by means of hot-air tape welding and subsequently investigated regarding its hydrostatic pressure resistance. The hydrostatic pressure resistance value of the conventional seam was then compared with ultrasonic weld seams of 6 and 12 mm welding width, and its parametric influence on the quality of the seam was analyzed. The result shows that the ultrasonic weld seam with a 12 mm welding width provided a higher hydrostatic pressure resistance than the 6 mm welding width and the conventionally sewn seam. Statistical analyses were also carried out to prove the significant effect of welding process parameters on hydrostatic pressure resistance, whereby the obtained results were statistically significant. A suitable nonlinear numerical model was also developed to predict the hydrostatic pressure resistance.

Effects of welding pressure on high-power ultrasonic spot welding of Cu/Al dissimilar metals

Although high-power ultrasonic welding (HPUSW) can provide better welding results about highly conductive materials, the welding mechanism is not well understood. In this study, the effects of welding pressure on dynamic process and joint characteristics (strength and fracture) of HPUSW were investigated. High pressure produces lower vibration amplitude of the upper and bottom specimens. Under excessive pressure, the vibration amplitude of sonotrode is significantly reduced, as compared to that under lower pressure during the initial welding period. The distribution of plastic strain follows the principle of crack growth and expansion. Excessive pressure results in the extrusion of trace elements from base material to the interface, which affects the process of interfacial diffusion. The maximum welding strength is obtained as the depth of penetration of sonotrode reaches its maximum value without the production of cracks. The results obtained in this work provide guidelines for optimizing the ultrasonic welding parameters.

Investigation of Imperfections Formed at the Ultrasonic Welding of Copper Sheets

Abstract Ultrasonic welding is a very useful and simple welding process. It is suitable for establishing a joint between thin sheets and dissimilar metals with short preparation and finish work time [1]. Some welding defects were detected due to less than optimal ultrasonic welding parameters. These defects were ruptures, surface colour change and unacceptable deformations. This article aims to identify these failures and their causes.

ВЛИЯНИЕ ПАРАМЕТРОВ УЛЬТРАЗВУКОВОЙ СВАРКИ НА ПРОЧНОСТЬ КОНТАКТНЫХ СОЕДИНЕНИЙ ВЫВОДОВ ИНТЕГРАЛЬНЫХ МИКРОСХЕМ

ВЛИЯНИЕ ПАРАМЕТРОВ УЛЬТРАЗВУКОВОЙ СВАРКИ НА ПРОЧНОСТЬ КОНТАКТНЫХ СОЕДИНЕНИЙ ВЫВОДОВ ИНТЕГРАЛЬНЫХ МИКРОСХЕМ

An Experimental Study on the Tensile Behaviors of Ultrasonic Welded T-joints for Polyamide Composite

In this paper, an experimental investigation on ultrasonic welding of polyamide composites reinforced with glass fiber has been carried out. The effect of ultrasonic welding parameters, such as welding time, air pressure, hold time and the amount of glass fiber in the composite on tensile strength of weld joints were determined using response surface methodology. This methodology was applied for developing a mathematical model which can predict the main effects of the above parameters and their impacts on tensile strength of T-welded ultrasonic joints in 4-mm thick polyamide composite sheets. The analysis of variance was performed to check the adequacy of the developed model. A comparison was also made between the predicted and actual results. The results showed that a maximum failure force of about 4759 N is obtained when vibration amplitude, air pressure welding time, holding time and amount of glass fiber are 35 microns, 3.6 bar, 1.84 seconds, 0.9 seconds and 41 percent, respectively .The joint strength of welded parts increased with the fiber content in the composites.