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A large stroke, high force paraffin phase transition actuator
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
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2002 (English)In: Sensors and Actuators A-Physical, ISSN 0924-4247, Vol. 96, no 2-3, 189-195 p.Article in journal (Refereed) Published
Abstract [en]

An actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated. The actuator consists of a ring-shaped paraffin cavity confined by two joint silicon diaphragms with rigid centers. When the paraffin is melted, the resulting hydrostatic pressure deflects the joined rigid centers in one direction only. The magnitude of the deflection is primarily a function of the geometrical relation between the two diaphragms, giving the opportunity to tailor the behavior of the actuator in a large range. Conventional IC-processing techniques have been used to fabricate a prototype with a width of 68 mm and a thickness of 825 μm. The prototype attained a maximum deflection of ca. 90 μm. Loaded with 3 N it still exhibits a deflection of ca. 75 μm. The device can be used as a thermal switch.

Place, publisher, year, edition, pages
2002. Vol. 96, no 2-3, 189-195 p.
National Category
Materials Engineering
URN: urn:nbn:se:uu:diva-89915DOI: 10.1016/S0924-4247(01)00785-3OAI: oai:DiVA.org:uu-89915DiVA: diva2:161775
Available from: 2002-05-16 Created: 2002-05-16 Last updated: 2013-06-13
In thesis
1. Miniature Phase-Transistion Actuators
Open this publication in new window or tab >>Miniature Phase-Transistion Actuators
2002 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Clearly, there is a need for simple, strong actuators capable of large strokes in miniaturized systems such as valves and optical shutters.

The basis for this work is the microstructure technology with processing techniques adopted from the integrated circuit industry. In many cases alternative techniques have been developed to obtain features not achievable with conventional silicon technology. Techniques to fabricate thermally activated phase transition actuators capable of large strokes, as well as strong, piezoceramic actuators, have been investigated

Multilayered piezoceramic actuators have been fabricated and used in a miniature linear motor. A technique to build freestanding, three-dimensional structures drop by drop using a micromachined ink jet head and a slurry of piezoceramic particles has been developed. Ion track technology was used to create narrow pores in polyimide. To make bimorph-like structures capable of large strokes, these pores were impregnated with paraffin- a material with a large volume expansion associated with its solid-to-liquid phase transition. Paraffin was used in a silicon thermal switch intended for a passive thermal control system, and in a device to be used as a valve in a gas regulation system. Finally, paraffin actuators for integration in thermoplastic microfluidic systems have been developed.

During the course of this work not only the importance of identifying the best materials for a given application has been addressed and acknowledged, but also that of finding a processing route on occasion far from the conventional one, and perhaps most important, that of anticipating the often surprising effects following from miniaturization.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2002. 28 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 728
Materials science, Materialvetenskap
National Category
Materials Engineering
Research subject
Materials Science
urn:nbn:se:uu:diva-2138 (URN)91-554-5345-7 (ISBN)
Public defence
2002-06-06, Ångströmslaboratoriet 2002, Uppsala, 09:30
Available from: 2002-05-16 Created: 2002-05-16Bibliographically approved

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Klintberg, LenaSchweitz, Jan-ÅkeThornell, Greger
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