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In this study, ultrasonic horns are designed by using vibration equations, vibration modal analysis and harmonic response analysis in order to compare welding performance when ultrasonic welding is performed at resonance frequencies of 20 kHz and 40 kHz. For the weldability evaluation of the manufactured horn for 20 kHz and 40 kHz, welding strength...
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The introduction of servo-driven ultrasonic technology provides a new level of control to an already fast and flexible welding method. This breakthrough has allowed greater consistency than ever before possible with ultrasonic welding, one of the most widely used processes for bonding polymers. In the medical industry, there is a great need for rel...
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... In contrast, the thickness of the bottom part is not limited as it is placed on the anvil and does not significantly affect the welding process. The thickness limit differs for different materials due to material properties, such as the hardness and their overall weldability [21][22][23]. ...
... The applied wavelength depends on the material and on the frequency used. This means that when the frequency changes, also the critical dimensions of the workpieces, at which the weld strength decreases significantly change [21,22]. The width of the top part perpendicular to the vibration direction has less influence on the weld strength. ...
Ultrasonic welding (USW) is a solid-state welding process based on the application of high frequency vibration energy to the workpiece to produce the internal friction between the faying surface and the local heat generation required to promote the joining. The short welding time and the low heat input, the absence of fumes, sparks or flames, and the automation capacity make it particularly interesting for several fields, such as electrical/electronic, automotive, aerospace, appliance , and medical products industries. The main problems that those industries have to face are related to the poor weld quality due the improper selection of weld parameters. In the present work, 0.3 mm thick copper sheets were joined by USW varying the welding time, pressure, and vibration amplitude. The influence of the process variables on the characteristics of the joints and weld strength is investigated by using the analysis of variance. The results of the present work indicate that welding time is the main factor affecting the energy absorbed during the welding, followed by the pressure and amplitude. The shear strength, on the other hand, resulted mostly influenced by the amplitude, while the other parameters have a limited effect. Regardless the welding configuration adopted, most welds registered a failure load higher than the base material pointing out the feasibility of the USW process to join copper sheets.
... Similarly, ultrasonic plastic welding conical sonotrodes offer better performance than other sonotrode profiles. In [5,6] it is experimentally estimated that for 20 kHz and 40 kHz horns the lower the frequency higher the weldability. The shape optimization of acoustic horns is performed using metaheuristic algorithms [7], but in which mesh size and geometry smoothing techniques are not considered. ...
Ultrasonic welding is a fast, clean and high energy process, no flux or filler metal is required, longer tool life and greater efficiency of a weld can be achieved in just a few seconds. Limited length and thickness of weld are the main drawbacks in this process. Welding of large length and thickness materials leads the ultrasonic welding applications unlimited. The design of the components like booster and sonotrode or horn in ultrasonic welding plays a vital role to improve the length and thickness of the welds by generating uniform amplitudes. In the present work, an ultrasonic sonotrode is designed to improve the weld length with suitable uniform amplitudes on the weld bed surface. The design of sonotrode is significantly difficult to obtain the uniform amplitudes at the large weld length. Here, rectangular sonotrode with multiple slots is designed based on theoretical calculations and numerical analysis is performed to obtain the maximum possible weld lengths with uniform amplitudes at a known operating frequency. The finite element method is used to analyze the actual resonating frequency and amplitude distribution of the sonotrode and obtained the maximum weld length as 400 mm for 15 kHz frequency with 3 slots. HIGHLIGHTS One of the major drawbacks in ultrasonic welding is limited length and thickness of weld. Welding of larger length and thickness improves the ultrasonic welding applications. Modal and harmonic analysis conducted in order to find the dynamic behaviour of the sonotrode. The increase in the weld length of the sonotrode deviates the amplitude distribution within the sonotrode. To overcome this non-uniform amplitude distribution, longitudinal slots are provided in the sonotrode. Also, these slots reduce the weight of the sonotrode.
... And the effect of pressure applied over the welding spot will decide if the weld strength and if it has been successful or still requires increment in the pressure for the fusion to take place for a successful joint. (5) The frequency to be used for the welding processes is 15-40 kHz, which is optimum for plastics and some metals, but Aluminum MMC is having higher tensile strength, the frequency may range up to 70 kHz for the process (Kim et al., 2017). (6) It has a frequency converter, which will use low power and starts to convert to electric power of high frequencies. ...
... (2) The frequency ranges involved in the welding process may have an adverse effect during the process, which usually ranges from 15 to 40 kHz is the usual range for plastics, for metals it may extend up to 70 kHz. Welding strength increases with the welding time under any conditions, at 40 kHz the welding strength is smaller than that at 20 kHz (Kim et al., 2017). This is due to friction heat between the metal sheets at a point where the horn tip is concentrated, and Aluminum diffusion is facilitated better at 20 kHz than at 40 kHz. ...
The Aluminum metal matrix with particulate reinforcements is the new future of the coming industrial revolution due to the higher strength and availability. Composite reinforcements such as SiC, TiB2, B4C, and others contribute significantly to the increased strength of the Aluminum metal matrix, which can be an optimal choice, also at a lower cost, in some applications where Aluminum is considered or proven to withstand high temperatures. Ultrasonic welding is the process, where, we get the electrical energy, which converts and amplifies into vibration energy for the welding to occur. The challenge we face today is the thickness limitations in ultrasonic welding. The ultrasonic welding of the Aluminum metal sheet with the reinforcements may affect it, as the addition of particulate reinforcements will increase the strength of the Aluminum matrix. Ultrasonic welding can only support a metal sheet with a thickness of up to 2.5 mm in the case of an Aluminum plain sheet. However, if the strength of the Aluminum metal matrix increases, the next step is to achieve ultrasonic welding with the same thickness of Aluminum matrix and reinforced composites that have greater strength than a standard Aluminum sheet. This review will focus on the parameters and the factors which may help decrease the difficulties of Ultrasonic Welding of Aluminum MMC, alongside reviewing the current technologies and research works.
... A smaller welding strength was found at 40 kHz than at 20 kHz while keeping all other parameters (i.e., pressure and amplitude) constant. [11] Different levels of process parameters such as weld pressure, time and amplitude affect the weld strength as well, and Taguchi method can be used to select an optimum set of process parameters for further micro-hardness and microstructural analysis. [12] The temperature at the weld interface is also affected by process parameters and can be co-related with joint strength. ...
Manufacturing of battery packs for electric vehicles requires joining at different levels such as cell level, unit level, and module level, which include the joining of highly conductive and dissimilar layers of thin metal foils. Conventional welding techniques such as fusion welding, resistance spot welding, and laser beam welding are not appropriate for the joining of multiple layers of metal foils with a comparatively thicker tab because they face difficulties in producing large weld nuggets and generate weld defects such as brittle phases. Ultrasonic welding, a solid-state technique, has been found to be the most successful joining process for battery pack manufacturing. Several studies focused on the joining of two layers of dissimilar materials while very few have successfully characterized the welding performance of multi-layer ultrasonic metal welding. In this study, a set of weld attributes was introduced, and weld parameters have been optimized for sound quality joints using optical microscopy and nanoindentation based on those attributes. Different failure types were associated with weld quality based on microscopic images of fractured specimens. A correlation between weld parameters and weld attributes (i.e., bond density and post weld thickness) was developed to provide some insights into their interdependencies.
