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A. Deutschinger, W. Brenner, B. Volland, K. Ivanova, T. Ivanov, I. Rangelow:
"Characterization of an electro thermal micro gripper by the use of a micro assembly station and dynamic SEM measurements";
Talk: 4M Cell handling and Actuation Follow-up Workshop, Wien; 06-19-2008 - 06-20-2008; in: "4M Cell handling and Actuation Follow-up Workshop", (2008).

In the last two decades a variety of micro gripper
types have been developed with different actuation
technologies. All types have different advantages and
disadvantages e.g. electrostatic, magnetic or thermal
disturbance of the local environment around the gripper.
Gripping in micro dimensions is problematic mainly
because of strong adhesion.
An electro thermal gripper, which has been
introduced by Ivanova, Volland et al. in [1] seems to be
a good candidate for a useful device for the
microsystems community. Therefore, several tests for
electrical and mechanical characterization issues have
been investigated in recent work, and an excerpt will be
presented in this paper. Some characteristics of the socalled
duo-action gripper (closed and open) are for
example a maximum opening width of 11.5 μm, a
minimum of 3.3 μm and 4 μm in the resting position.
The maximum input power has been determined to be
50...80 mW per actuator, resulting in a current density in
the cross-section of the actuator´s metal layer of up to
1,27 MA/cm2. At higher values it seems that
electromigration occurs as a result of the high current
density and temperature (≈200 °C) and the metal layer
on the gripper suffers damage. Other characteristics have
been investigated such as the cut-off frequency and
undesirable effects such as z-deflection and an increase
in length. Gripping experiments will be conducted after
optimisation of performance.

Project Head Werner Brenner:
Methoden und Werkzeuge für Handhabung und Montage in der Mikrodimension (Tech. abgeschlossen 2007)