Dynamic correction of oscillatory forces during ultrasonic-assisted metal forming

Michalski, Markus; Leicht, Uwe; Heath, Andrew C.; Merklein, Marion

doi:10.1007/s11740-017-0762-3

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…In Ref. [12], it is described how the dynamic measured force can be corrected dependent on the frequency for ultrasonicassisted forming processes.…”

Section: Press-fit With Ultrasoundmentioning

confidence: 99%

Ultrasonic excitation during press-fit joining of electrical contacts

Halm

Otto

Stark

et al. 2020

Int J Adv Manuf Technol

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Ultrasonic excitation of pins during a press-in process can reduce the press-in force. There are various theories describing the reason for the force reduction. In this paper, the printed circuit board (PCB) was excited to reduce the press-in force. The advantages of this process in comparison with the excitation of the pin are its suitability for already embedded pins. Another point is that several pins at the same time can be joined with the PCB. A new pin geometry was developed, and an appropriate aluminum-based alloy was chosen to show the effects of ultrasonic excitation. The influence of the amplitude of the ultrasound on the press-in force and the deformation of pin and plated through hole (PTH) were studied. With an excitation amplitude of 20 μm, the press-in force could be reduced by more than 80%. Furthermore, it is found that the force needed for plastic deformation and the friction are reduced by ultrasound. The higher the amplitude, the more deforms the PTH while the pin deforms less.

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“…In Ref. [12], it is described how the dynamic measured force can be corrected dependent on the frequency for ultrasonicassisted forming processes.…”

Section: Press-fit With Ultrasoundmentioning

confidence: 99%

Ultrasonic excitation during press-fit joining of electrical contacts

Halm

Otto

Stark

et al. 2020

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…For this purpose, the staking die is excited with an impact hammer and the output is measured with the force sensor. This way, the determination of the transfer function is possible by means of the approach in 17 and dynamic forces are evaluated correctly.…”

Section: Methodsmentioning

confidence: 99%

“…However, in the high-frequency range, the gauging of oscillating forces is highly affected by the setup's frequency response and thus, by the position of the force sensor and dynamic behavior of the whole setup. 17 Hence, the determination of the transfer function is needed. With regard to ultrasonic-assisted joining processes, previous studies focused merely on the mean forces, remained unclear with regard to force measurement, or limited the significance with respect to the oscillating forces.…”

Section: Introductionmentioning

confidence: 99%

A novel ultrasonic-assisted staking process for mechanical fasteners

Jäckisch

Merklein

2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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Increasing material variety in car body engineering causes new challenges regarding the joining processes and therefore, leads to an enhanced usage of mechanical joining technologies. Mechanical fasteners, as self-piercing nuts, can be staked cost-efficiently without a pre-punching operation to create detachable joints. Nevertheless, elevated workpiece strengths lead to high forming forces and a limited application range. One promising approach to reduce tool and workpiece loads in forming operations is superimposing a high-frequency oscillation to the tool movement. The so-called ultrasonic assistance enables an immediate and considerable reduction of the material's flow stress. This beneficial softening effect has been confirmed for several materials and processes. Since the process management and monitoring are highly affected by the frequency-dependent dynamic behavior of the whole test setup, the application of ultrasonic assistance is already challenging for basic forming operations. Hence, only a few studies have been investigating ultrasonic-assisted joining processes. In particular, joining processes with auxiliary elements have been hardly considered. Within the scope of this work, a novel ultrasonic-assisted staking process for mechanical fasteners is proposed. Therefore, the punch movement for the installation of a self-piercing nut into an aluminum sheet is superimposed with a 20 kHz oscillation of 10 µm, 15 µm, and 20 µm amplitude. Ultrasonic assistance in the initial staking phase, characterized by moderate loads, causes irregular tool–specimen contact. Since the effect is promoted by increasing amplitudes, a correlation with the elastic tool deflection is presumed. Additionally, the transferability of the ultrasonic-based force reduction to mechanical joining with auxiliary element is confirmed and a beneficial influence on the joint formation is identified. Thus, ultrasonic assistance is proven as a promising approach for the extension of existing process limits.

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Influence of Ultrasonic Assistance on the Forming Limits of Steel

Jäckisch

Merklein

2021

Forming the Future

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Dynamic correction of oscillatory forces during ultrasonic-assisted metal forming

Cited by 9 publications

References 8 publications

Ultrasonic excitation during press-fit joining of electrical contacts

Ultrasonic excitation during press-fit joining of electrical contacts

A novel ultrasonic-assisted staking process for mechanical fasteners

Influence of Ultrasonic Assistance on the Forming Limits of Steel

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