Detection of terminal oscillation pattern in ultrasonic metal welding

Mostafavi, Shimaalsadat; Hesser, Daniel Frank; Markert, Bernd

doi:10.1016/j.jmapro.2019.03.035

Cited by 18 publications

(9 citation statements)

References 20 publications

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“…According to literature review, only Mostafavi et al [12] observed sidebands in the oscillations during the welding process; however, it has to be noted that only few research groups investigated the oscillation behavior of one or more components during USMW of terminals and stranded wires. As Balz et al [14] as well as Abi Raad et al [13] did not observe sidebands, the assumption can be made that the emergence of sidebands depends on the geometry and/or the material of the joining partners.…”

Section: Resultsmentioning

confidence: 99%

“…Inter alia Mostafavi translated the findings of this work into the observations he made at his investigations. He proposed that sidebands are occurring during USMW when a change of relative motion between components is taking place [12]. Following this assumption, the relative motion between anvil, terminal, and wire changes when increasing the weld time beyond the optimal parameter set, thus performing over-welding, as sidebands were detected for these components.…”

Section: Resultsmentioning

confidence: 99%

“…Although USMW is widely used for this type of joints whereas ultrasonic oscillation is the main driver for the frictional heat, disruption of passivation layers, and other effects, only few literature exist on the investigation of the oscillation behavior of the USMW components during the joining of wires and terminals. Mostafavi et al investigated the influence of terminal modifications on the time and frequency domains during the welding procedure of brass terminal/aluminum wire joints via piezoelectric transducers mounted on the terminals [12]. The signals observed also exhibited the existence of strong harmonics at multiples of 2 to 5 based on the fundamental frequency.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the oscillation behavior during ultrasonic welding of EN AW-1070 wire strands and EN CW004A terminals

et al. 2021

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For fulfilling the demand of durable yet lightweight electrical connections in transportation industries, ultrasonic metal welding (USMW) sees widespread use in these branches. As the ultrasound oscillations utilized in the welding procedure occur at a range of only a few micrometers at frequencies of 20–100 kHz for an overall duration of only 50–1500 ms, it is not possible to observe the compaction behavior with the bare eye. This paper focusses on investigating the oscillation behavior of the horn, the anvil, and the joining partners during the welding procedure by utilizing an array of synchronized laser vibrometers and performing welds with incrementing time stages. The oscillation data is correlated with temperature measurements in the welding zone as well as tensile testing results. Inter alia the formation of sidebands at the fundamental frequency as well as 2nd- and 3rd-order harmonics has been observed for the anvil, terminal, and wire front face when exceeding optimal weld time which would lead to maximum joint strength. Following the assumption of other research groups, the cause of these sidebands could be a change in relative motion of these components. As the terminal is slipping with increasing weld time, it could be assumed that the reason for the sidebands is low-frequency movement of the anvil, modulated onto the fundamental frequency, additionally indicating successful bonding of the stranded wire and the terminal. Furthermore, this slipping of the terminal on the anvil could lead to increased wear of the anvil knurls.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Analysis of the oscillation behavior during ultrasonic welding of EN AW-1070 wire strands and EN CW004A terminals

et al. 2021

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“…At the cross section in Figure 7b, the bond line was not observed due to the characteristics of solid phase bonding. When resistance welding, the bond line is observed but both heat affected zone and bonding line are not observed, since ultrasonic metal welding is one of the plastic-flow welding methods [26,27]. However, it was confirmed that two metals were closely bonded to each other after observing the weldment under 3000 times magnification, as shown Figure 7c.…”

Section: Evaluation Of Mechanical Joint Performancementioning

confidence: 95%

An Analysis of Mechanical Properties for Ultrasonically Welded Multiple C1220-Al1050 Layers

Kim

et al. 2019

Applied Sciences

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This study analyzed the characteristics of aluminum and copper sheets under multi-layer ultrasonic welding, and observed the strength, fracture type, and interface of the weld zone according to location. In addition, an experimental plan was developed using the Taguchi method to optimize the quadruple lap ultrasonic welding process conditions of 0.4t aluminum and copper sheets, and the experiment was performed for each of 25 welding condition. For strength evaluation, the ultrasonic welding performance was evaluated by measuring the tensile strength as a composite material and the shear force at the weld interface through two types of tensile tests: simultaneous tensile and individual tensile. To identify the individual shear strengths of the multi-layer dissimilar ultrasonic welds, three types of tensile tests were performed for each specimen depending on the location of the welded, and as the distance from the horn increased, each of shear strength decreased while the difference in strength value increased. For quadruple lap welding of pure aluminum and copper sheets, the S/N (Signal to Noise Ratio) was the highest at 64.48 with a coarse-grain pattern and optimal welding conditions, and this was selected as the optimal condition. To evaluate the optimized welding condition, additional tests were conducted using the welding conditions that showed the maximum strength values and the welding conditions optimized using the Taguchi method through simple tests. A strength evaluation of the optimized weldment was performed, and for a simultaneous tensile test, it was found that the strength of the optimized weldment was improved by 45% compared to other cases.

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“…However, the intriguing major aspects of USMW are topics of profound research for decades. This includes the effect of the process parameters on the interface temperature growth from realtime monitoring [34,66], derivation of the frequency content of the ultrasonic vibrations in the mating parts [35] and depiction of sonotrode vibration trajectories [46].…”

Section: Introductionmentioning

confidence: 99%

Molecular dynamics simulation of interface atomic diffusion in ultrasonic metal welding

Mostafavi

Bamer

Markert

2021

Int J Adv Manuf Technol

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The formation of a reliable joint between a large number of aluminum strands for battery applications is crucial in automotive industry, especially in the technology of autonomous vehicles. Therefore, in this study, mechanical deformations and diffusion patterns of the mating interface in ultrasonic welding of aluminum were investigated using molecular dynamics simulations. Furthermore, microscopic observations of the joints between aluminum strands from ultrasonic welding illustrating the influence of two process parameters were done. To study the nanomechanics of the joint formation, two aluminum crystallites of different orientations were built. The impact of the sliding velocity and the compression rate of the upper crystal block on the diffusion pattern at the interface of the two crystallites were quantified via the diffusion coefficient. Tensile deformations of several joint configurations were performed to investigate the load-bearing capacity of the solid state bond, taking into account the compression rate, the sliding velocity and the crystallite orientation. The atomic scale simulations revealed that the orientations of the crystallites govern the interface diffusion and the tensile strength of the joint significantly. Furthermore, interface atom diffusion increased with increasing the sliding velocity. Additionally, it was observed that a higher sliding velocity enhances the friction heat generation between the crystallites and significantly increases the interface temperature.

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Detection of terminal oscillation pattern in ultrasonic metal welding

Cited by 18 publications

References 20 publications

Analysis of the oscillation behavior during ultrasonic welding of EN AW-1070 wire strands and EN CW004A terminals

Analysis of the oscillation behavior during ultrasonic welding of EN AW-1070 wire strands and EN CW004A terminals

An Analysis of Mechanical Properties for Ultrasonically Welded Multiple C1220-Al1050 Layers

Molecular dynamics simulation of interface atomic diffusion in ultrasonic metal welding

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