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Micromachines 2017, 8(6), 182;

Reliable and Accurate Release of Micro-Sized Objects with a Gripper that Uses the Capillary-Force Method

Laboratory of Cognitive Systems in Mechatronics, Faculty of Electrical Engineering and Computer Science, University of Maribor, SI-2000 Maribor, Slovenia
Author to whom correspondence should be addressed.
Academic Editor: Nam-Trung Nguyen
Received: 22 March 2017 / Revised: 30 May 2017 / Accepted: 3 June 2017 / Published: 8 June 2017
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There have been recent developments in grippers that are based on capillary force and condensed water droplets. These are used for manipulating micro-sized objects. Recently, one-finger grippers have been produced that are able to reliably grip using the capillary force. To release objects, either the van der Waals, gravitational or inertial-forces method is used. This article presents methods for reliably gripping and releasing micro-objects using the capillary force. The moisture from the surrounding air is condensed into a thin layer of water on the contact surfaces of the objects. From the thin layer of water, a water meniscus between the micro-sized object, the gripper and the releasing surface is created. Consequently, the water meniscus between the object and the releasing surface produces a high enough capillary force to release the micro-sized object from the tip of the one-finger gripper. In this case, either polystyrene, glass beads with diameters between 5–60 µm, or irregularly shaped dust particles of similar sizes were used. 3D structures made up of micro-sized objects could be constructed using this method. This method is reliable for releasing during assembly and also for gripping, when the objects are removed from the top of the 3D structure—the so-called “disassembling gripping” process. The accuracy of the release was lower than 0.5 µm. View Full-Text
Keywords: micro-objects; one-finger gripper; gripping; releasing; capillary force micro-objects; one-finger gripper; gripping; releasing; capillary force

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Uran, S.; Šafarič, R.; Bratina, B. Reliable and Accurate Release of Micro-Sized Objects with a Gripper that Uses the Capillary-Force Method. Micromachines 2017, 8, 182.

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