Automated assembly of hingeless 90° out-of-plane microstructures

Tsang, See-Ho; Sameoto, Dan; Foulds, Ian G.; Johnstone, Robert W.; Parameswaran, M.

doi:10.1088/0960-1317/17/7/014

Cited by 30 publications

(27 citation statements)

References 16 publications

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“…These elastic instabilities offer a new form of actuation. For example, buckling, as a design principle, has been used to actuate soft robots, to make tunable metamaterials, to fabricate complex micro/nanomaterials, and control adhesive surfaces . We have demonstrated that reversible buckling of elastomeric beams may be employed for torsional soft actuators by applying negative pressure to an elastomeric structure made of interconnected cavities that reversibly deform, and for linear actuators inspired by muscle …”

mentioning

confidence: 99%

Fabricating 3D Structures by Combining 2D Printing and Relaxation of Strain

Cafferty

Campbell

Rothemund

et al. 2018

Adv Materials Technologies

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materials to achieve extreme overhangs, and are limited by trade-offs between the speed of printing and the minimum feature sizes and surface roughness. [8,9] In contrast, "2D printing" techniques (such as digital printing and screen printing) are rapid, relatively inexpensive, and routinely achieve sub-millimeter feature sizes.Nature has also evolved the ability to form complex 3D structures (e.g., leaves, flowers, and tendrils) from initially quasiplanar structures. [10][11][12][13][14][15] These 2D to 3D transformations have inspired the design of synthetic structures that display complex changes in shape when subjected to appropriate stimuli (surface or interfacial stress, edge stress, misfit strain, residual stress, differential growth, swelling, and mechanical instabilities). [16,17] These processes also suggest possible routes to micro-and nanoelectromechanical systems (MEMS and NEMS), [18,19] and to systems for drug delivery, [20] actuation, [19,21] microrobotics, [22,23] and new materials. [23,24] In this paper, we describe a technique to fabricate 3D structures from planar elastomeric bilayers with mismatched strain that is compatible with digital printing. We determine that a relatively simple set of primitive structures printed on a prestretched 2D sheet can result in a variety of complex 3D objects by producing both positive and negative curvature of whole parts, as well as "pop-up" structures on 2D or 3D sheets. This paper describes the fabrication of elastomeric three-dimensional (3D) structures starting from two-dimensional (2D) sheets using a combination of direct-ink printing and relaxation of strain. These structures are fabricated in a two-step process: first, elastomeric inks are deposited as 2D structures on a stretched elastomeric sheet, and second, after curing of the elastomeric inks, relaxation of strain in the 2D sheet causes it to deform into a 3D shape. To predict bending of elastomeric objects fabricated with this technique, a simple mechanical model is developed. The strategy of using initially 2D materials to fabricate 3D structures offers four new features that complement digital fabrication techniques. (i) It provides a simple route to create shapes with complex curves, suspended features, and internal cavities. (ii) It is a faster method of fabricating some types of shapes than "conventional" 3D printing, because the features are printed in 2D. (iii) It forms surfaces that can be both smoother, and structured in a way that is not compatible with layer-by-layer processing. (iv) It forms structures that can be deformed reversibly after fabrication by reapplying strain. This paper demonstrates these features by fabrication of helices, structures inspired by cubes and tables, "pop-up" structures, and soft grippers. 3D PrintingThe term "3D printing" encompasses additive manufacturing techniques that use one or more translational elements (stage and/or printing heads) that are controlled by a computer to move an ink deposition nozzle, or laser-writing optics, to fabricate a digitally ...

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mentioning

confidence: 99%

Fabricating 3D Structures by Combining 2D Printing and Relaxation of Strain

Cafferty

Campbell

Rothemund

et al. 2018

Adv Materials Technologies

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“…As demonstrated by Tsang et al, 23 various SU-8 planar components attached to long serpentine springs were fabricated and anchored to the substrate. The out-of-plane assembly of these components was accomplished by pushing the planar structures laterally until they rotated to the desired 901 position.…”

Section: Parts and Actuatorsmentioning

confidence: 99%

SU-8 for Microsystem Fabrication

Chiu

Cheng

2014

Photocured Materials

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SU-8 is a negative-tone photoresist that can be used to fabricate thick, high aspect ratio structures. The thickness of SU-8 structures ranges from several micrometers to several hundred micrometers or up to millimeters by direct spin coating or stacking of multiple layers of dry films. Being a negative resist, SU-8 can be used to fabricate complex three-dimensional structures such as sealed microchannels or tilted optical surfaces by multiple exposures. Another feature of SU-8 is that its properties can be controlled and modified during processes by the exposure doses, baking temperature, or even additives. This provides possibilities for novel device design and fabrication without complex fabrication processes. SU-8 has relatively low loss and absorption in the RF and visible spectral ranges, therefore, it has been used to fabricate various sensing, optical, and RF components and systems. This chapter summarizes the basic material properties and fundamental fabrication processes of SU-8. Examples of various structures, actuators, sensors, and fluidic/optical/RF components are presented to demonstrate the wide possibility of devices that can be implemented in SU-8.

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“…The test structures were then placed on microstructures, which could be manually assembled vertical to the substrate after fabrication [7]. Using the vertical stages, side view of the curvature test structures was captured (figure 5), which was analyzed for curvature measurements and geometrical parameter extractions.…”

Section: Test Structuresmentioning

confidence: 99%

“…Research areas that can benefit from three-dimensional microstructures are micro-optics, micro-sensors, micro-actuators, and micro-antennas. MEMS structures can be either assembled after fabrication is completed [7] or during a fabrication process [1,8]. These two types of assemblies can be either assisted by external means [7,8] or developed from stress induced within the structures [1,9].…”

Section: Introductionmentioning

confidence: 99%

Polymer MEMS fabrication process for self-assembled millimeter-wave on-chip antennas

Lee

Parameswaran

2011

2011 16th International Solid-State Sensors, Actuators and Microsystems Conference

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A novel micro-electro-mechanical systems (MEMS) fabrication process for self-assembled antennas has been characterized. Self-assembled vertical monopole antennas were previously reported [1]. The vertical on-chip antennas provide higher efficiency over conventional planar on-chip antennas. However, the metallization step of the antennas was performed after the release and self-assembly of the devices resulting in minimal deposition of metal on the backside of the antennas. In the presented work, two separate metallization steps are performed before and after the structural layers are patterned to achieve an even thickness of metal layers on both the top and bottom surfaces of the antennas in order to reduce dielectric loss. Additionally, bridging structures are integrated between the stress-inducing blocks to further enhance self-assembled curvatures with a brief exposure of SU-8.

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Automated assembly of hingeless 90° out-of-plane microstructures

Cited by 30 publications

References 16 publications

Fabricating 3D Structures by Combining 2D Printing and Relaxation of Strain

Fabricating 3D Structures by Combining 2D Printing and Relaxation of Strain

SU-8 for Microsystem Fabrication

Polymer MEMS fabrication process for self-assembled millimeter-wave on-chip antennas

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