SWISS FOCUS | ARTICLE
<< Figure 3: Flex-Gripper for medical needles (diameter 0.3-0.7 mm). Monolithic micro gripper developed for an
automatic assembly machine to hold a medical needle, this gripper has been tested during more than four million cycles with success. The flexure kinematics ensure high repeatability and a symmetric aperture. >>
>> Continued from page 9
On the other hand, due to their physical principles, flexures do present some limitations such as:
• Limited stroke • Restoring force • Complex kinematics • Limited load capacity
Example of applications: are found in figures 1 and 2 Figure 1: The innovative design of the flexure used as guiding principle, avoids any friction, wear and backlash. Thanks to the specific design, only one actuator is needed to keep angular error below 15 µrad over the full travel range. The first resonant frequency is up to 395 Hz.
Figure 2: Axes dedicated to micro electrical discharge machining need to have very high dynamic response in terms of movement, in order to be more efficient. Nevertheless, high accuracy is also required. A tailored micro positioning device with strokes of 5 mm, resolution of movements of a few nanometre and vibration modes higher than 400 Hz was developed and successfully tested.
Conclusion Increasing demands for systems more efficient in terms of precision, dynamics or cleanliness make the use of flexible structures more and more interesting. New technology such as Femtoprint opens more possibilities for manufacturing flexures out of fused silica, increasing the potential for new products. With flexures it is indeed possible to create new mechanisms with outstanding features.
Reference: On the bending strength of fused silica flexures fabricated by ultrafast lasers, Yves Bellouard, Optical Materials Express, Vol. 1, Issue 5, pp. 816-831 (2011).
MECARTEX SA
www.mecartex.ch
New technology such as Femtoprint opens more possibilities for manufacturing flexures out of fused silica, increasing the potential for new products. With flexures it is indeed possible to create new mechanisms with outstanding features.
<< Figure 4: Flexible joint out of fused silica. >>
10 | commercial micro manufacturing international Vol 6 No.6
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