Ultrasonic-Assisted Metal Staking with 15 kHz Oscillation Frequency

To comply with increasing product requirements, the use of function-optimized materialsis claimed. Joining technology thereby becomes increasingly important to use high strength materialonly in postulated sections. Staking is a joining by forming technology that is highly reliable andcost efficient. High process forces and sufficient formability of the material limit the suitability inclaimed miniaturization for use in industrial applications. A promising approach to break these processlimitations is the use of superposed high frequency oscillation, whereby joining forces could bedecreased. The present study indicates first trials of an ultrasonic (US) assisted staking process of highstrength martensitic steel. Based on high temporal instrumentation, such as laser vibrometer, contactdetection and high-resolution force measurement, the process sequence is characterized and studiedin detail. The researches confirm high potential in force reduction of mean values due to superimposedhigh frequency oscillation with a high dependency on amplitudes. In process, two differentforce-characteristics within three regimes can be identified. Since US assisted forming processes arewell known in literature with harmonic oscillating force signals during process, hammering and soirregular force peaks with changes in contact signal within process, are identified for first time anddemonstrate a highly promising field of application.

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Ultraschallunterstützte Umformung von Metallen*/Ultrasonic-assisted forming of metals - Development of a test bench for material characterization with 15 kHz ultrasonic vibrations

wt Werkstattstechnik online ◽

10.37544/1436-4980-2015-10-51 ◽

2015 ◽

Vol 105 (10) ◽

pp. 715-721

Author(s):

M. Michalski ◽

M. Merklein

Keyword(s):

High Frequency ◽

Material Characterization ◽

Test Bench ◽

Flow Behavior ◽

High Frequency Oscillation ◽

Experimental Investigations ◽

Metallic Materials ◽

Frequency Oscillation ◽

Ultrasonic Assisted ◽

Forming Tools

Umformwerkzeuge, die mit einer hochfrequenten mechanischen Schwingung überlagert werden, ermöglichen eine deutliche Reduzierung der benötigten Umformkräfte. Darauf aufbauend werden am Lehrstuhl für Fertigungstechnologie experimentelle Untersuchungen mit verschiedenen metallischen Werkstoffen durchgeführt, um deren Fließverhalten bei Ultraschallüberlagerung mit 15 kHz zu charakterisieren. Die aktuelle Studie befasst sich mit der Entwicklung und der Qualifizierung eines geeigneten Prüfstands.   Forming tools that are superimposed with a high frequency oscillation enable a considerable reduction of the required forming forces. On this basis experimental investigations with various metallic materials are conducted at the Institute of Manufacturing Technology to characterize the flow behavior during ultrasonic-assisted forming with 15 kHz oscillation frequency. This study is concerned with the development and the qualification of a suitable test bench.

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Ultraschallunterstütztes Umformen und Verstemmen/Ultrasonic-assisted forming and caulking – Current results of the joint research project “UltraCaulk”

wt Werkstattstechnik online ◽

10.37544/1436-4980-2017-01-02-54 ◽

2017 ◽

Vol 107 (01-02) ◽

pp. 52-58

Author(s):

U. Leicht ◽

M. Michalski ◽

M. Merklein

Keyword(s):

High Frequency ◽

Material Flow ◽

High Frequency Oscillation ◽

Research Project ◽

Joint Research ◽

Influence Of Process Parameters ◽

Joint Research Project ◽

Ultrasonic Assisted ◽

Force Reduction ◽

Ultrasonic Influence

Durch Überlagerung hochfrequenter Schwingungen in Umformprozessen können Prozesskräfte deutlich reduziert werden. Im Verbundprojekt UltraCaulk wird daher neben grundlegenden Untersuchungen zur Charakterisierung des Werkstoffverhaltens unter Ultraschall auch die Übertragbarkeit identifizierter Mechanismen auf den industriellen Verstemmprozess untersucht. Der Fachbeitrag beschreibt den Zusammenhang zwischen verschiedenen Prozessparametern und der resultierenden Kraftreduzierung sowie der Probenerwärmung.   Substantial force reductions can be achieved by superimposing high frequency oscillation on forming processes. The joint research project UltraCaulk focusses on fundamental investigations on the material flow behaviour during ultrasonic influence and the transferability of identified mechanisms on industrial caulking processes. This study analyses the influence of process parameters on the resulting force reduction and specimen heating.

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Analysis of the Cutting Force With Ultrasonic Assisted Manufacturing of Steel (S235JR)

Volume 2: Advanced Manufacturing ◽

10.1115/imece2017-71238 ◽

2017 ◽

Author(s):

Philipp Zopf ◽

Franz Haas

Keyword(s):

Cutting Force ◽

Force Measurement ◽

Positive Influence ◽

Drilling Process ◽

Application Range ◽

Manufacturing Method ◽

First Case ◽

Ultrasonic Assisted ◽

Hard And Brittle Materials ◽

Force Reduction

The manufacturing of hard and refractory materials such as ceramics, glass or carbide poses particular challenges on tools and machines. The Sauer Limited a company of the DMG Mori Corporation has developed ultrasonic tool holders working in a frequency range from 15 to 60 kHz. The ultrasonic vibrations are superimposing the tool movement in the tool axis especially for the application on special materials. This technique causes a structural weakening in the contact area and facilitates the machining. For these special materials, a force reduction, mainly in drilling into carbide with diamond tools, of up to 30 percent is possible. This made the authors try to expand the application range of this method. To achieve evaluable results, the authors decided to start working with existing processes. This also makes it easier to understand the mechanism of the positive influence of the ultrasonic assistance. It is difficult to compare a grinding process of hard and brittle materials to the drilling of steel as these two operations are different in many ways. In the first case of investigation, the authors use tools with geometrically undefined edges, where as in the second case, the edges are geometrically defined. To get valid results of the tests, it has then been decided to investigate drilling. This manufacturing method anticipates the best results. The main target of the investigation is to reduce the cutting force. It is measured with a force measurement platform underneath the workpiece. Concerning the direction of the ultrasonic assistance, the authors expect lower cutting forces, longer endurance of the tool, a reduction of the burr height and a better surface quality in the drilling process. To verify the frequencies and the amplitudes, an FFT-analysis is performed. This analysis shows the increase of the damping. This raise depends on the infeed rate of the tool and thus reduces the amplitude of the cutting force.

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Ultrasonic Assisted Clinching of Aluminium Alloy Sheets

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.966-967.641 ◽

2014 ◽

Vol 966-967 ◽

pp. 641-650 ◽

Cited By ~ 2

Author(s):

Frederik Heßeln ◽

Martin Christoph Wanner

Keyword(s):

Aluminium Alloy ◽

High Strength Steel ◽

High Strength ◽

Forming Force ◽

Research Activity ◽

Positive Effects ◽

Current Research Activity ◽

Ultrasonic Assisted ◽

Force Reduction ◽

Ultrasonic Softening

Ultrasonic assisted clinching applies ultrasonic energy to the punch during the process. Prior studies detected a forming force reduction [1]. Current research activity focusses on the possibility to use the positive effects of ultrasonic softening mechanisms in clinching processes to join high-strength steel and aluminium. An ultrasonic unit with a power of 1 kW was installed into a c-shaped clinching bow to overlay a vibration with a frequency of 20 kHz onto the clinching process. This Paper describes the integration of the ultrasonic unit in the clinching process and presents current research results focusing on concept verification.

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Tool System for Ultrasonic-Assisted Forming and Material Characterisation with 15 kHz Oscillation Frequency

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.794.427 ◽

2015 ◽

Vol 794 ◽

pp. 427-434 ◽

Cited By ~ 4

Author(s):

Markus Michalski ◽

Uwe Leicht ◽

Sebastian Engler ◽

Marion Merklein

Keyword(s):

Load Capacity ◽

High Strength ◽

Soft Materials ◽

Compression Tests ◽

Oscillation System ◽

Oscillating Systems ◽

Ultrasonic Assisted ◽

Force Reduction ◽

Oscillation Frequencies ◽

High Sound

It is well-known that superimposed ultrasonic tool vibrations are capable of decreasing the forming force and the interfacial friction during the deformation of metal. The complex causes of this phenomenon were mainly investigated by focusing on oscillation frequencies above 20 kHz. Due to limitations of the load capacity and the power of the oscillating systems, mostly soft materials, such as aluminium and copper, were analysed. The present study is concerned with the development of a tool system for ultrasonic-assisted compression tests with a 15 kHz oscillation system. The advantages of this type of oscillating system are an increased power and robustness, which allow the testing of high strength materials. In preliminary ultrasonic-assisted compression tests with a S235JR steel a force reduction of up to 63 % was measured. The major challenges identified during the preliminary investigations are a transversal drift of the specimen, a periodic separation between the die and the specimen, a high sound emission and a high demand on the measuring and signal processing technology. Based on the technical challenges and the determined requirements a tool system is introduced.

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