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Additive manufacturing processes
Published in Fuewen Frank Liou, Rapid Prototyping and Engineering Applications, 2019
In the UC process, a sonotrode is a textured cylinder that clamps the additive layer or foil (or tape) to the substrate and vibrates at ultrasonic frequencies and micron-scale amplitudes. In the ideal case, the sonotrode and new layer move together, and the vibration energy is transferred from the sonotrode/tape interface zone into the tape/substrate interface. This tape/substrate interface deformed region, called deformation affected zone, experiences plastic deformation that breaks and disperses surface oxides and contaminants, thereby bringing atomically clean metal surfaces into contact and creating a true metallurgical bond.
Fundamentals of Ultrasonic Spot Welding
Published in Susanta Kumar Sahoo, Mantra Prasad Satpathy, Ultrasonic Welding of Metal Sheets, 2020
Susanta Kumar Sahoo, Mantra Prasad Satpathy
The discovery of piezoelectric crystals resulted in successful implementation in the ultrasonics field for various applications. In subsequent years, the intensity of the acoustic power has been increased to produce high-power acoustics, achieved through the development of different allied components [14, 15]. One of the important parts of the ultrasonic welding system is the acoustic horn/sonotrode. It primarily serves two functions: magnifying the amplitude of mechanical vibration required for welding and also acting as a tool which is directly in contact with the workpiece. The ultrasound waves are transmitted through the sonotrode and applied to the welding surface. Thus, any oxide layers or other contaminants on the faying surface are dispersed due to high-frequency vibration, and proper metal-to-metal contact takes place. By that time, the metals have been heated due to interatomic vibration and interfacial friction, which promotes deformation of the material. Many researchers are focused on the various horn design criteria and have performed numerous experiments on different horns to validate their views. In most cases, equations for the horn are derived to compute its resonant length and amplitude gain. Such an analysis is carried out by taking a non-uniform bar, which was excited in a longitudinal vibration mode. This study also demonstrated the effects of the various horn shapes, such as conical, exponential, and catenoidal. Out all of these, catenoidal horns showed the largest amplitude gain [16]. With the support of such studies, many researchers conducted ultrasonic machining experiments using different horns, such as the cylindrical, tapered, and exponential types. Modal and harmonic analysis of horns was also carried out by using finite element analysis. It was noticed that the proper sonotrode shape depends upon the fundamental factors like resonance frequency and the amplitude factor at the output of the sonotrode tip. Moreover, these sonotrode dimensions were also influenced by the stiffness and slenderness ratio [17]. Thus, for getting high amplitude at the sonotrode tip, a new type of horn design is considered, which is superior to other regular horn designs. Generally, resonance frequency depends on the length of the horn, and amplitude depends on the varying cross-sectional area. To manufacture the various horns, size must be reduced from larger diameters to a small horn tip diameter, which may be time-consuming. Thus, a novel folded-type sonotrode was designed and modeled for applications where reduction in dimensions and weight is the prime concern [18]. Furthermore, in order to obtain maximum amplitude magnification, and a higher material removal rate with safe working stress in ultrasonic machining of hard and brittle materials, a new type of horn design was suggested with the help of finite element analysis. The newly designed sonotrode was manufactured without the computer numerical controlled (CNC) machines, and its design was much simpler than that of the exponential sonotrode. It also provided higher amplitude magnification than traditionally designed sonotrodes [19]. A schematic representation of various traditionally designed horns is presented in Figure 2.7.
Optimization of process parameters of ultrasonic metal welding for multi layers foil of AL8011 material
Published in Welding International, 2023
Shah Samir, Komal Dave, Vishvesh Badheka, Dhaval Patel
Solid-state welding generated by ultrasonic metal welding requires high-frequency vibrations and moderate pressure and can be performed on similar or dissimilar metallic work parts. There are primarily four components that make up the ultrasonic welding system. The four components of the system are the transducer, electronic power supply, anvil and clamping mechanism as shown in Figure 1, By employing an ultrasonic transducer, the power supply supplies high-frequency electronic power. For this type of welding, a tool called a sonotrode generates high-frequency mechanical vibrations, which are sent to the workpiece via an auditory connection device. While welding, the anvil holds the workpiece steady and provides a tight clamping force. There are two primary kinds of ultrasonic welding systems. two-part wedge reed system, one-part lateral drives the latest research indicates that ultrasonic welding methods made use of a lateral driving mechanism. The anvil in lateral drive systems is ruggedly constructed to withstand bending and sustain the static clamping force employed to hold the workpiece [2].