Rapid Prototyping of Microactuators by Integrating 3D Printed Polymeric Structures with NiTi Thin Film

Velez, Camilo; Kim, Suk-Jun; Babaei, Mahnoush; Patel, Dinesh K.; Knick, Cory R.; Smith, Gabriel L.; Bergbreiter, Sarah

doi:10.1109/mems46641.2020.9056231

Cited by 12 publications

(3 citation statements)

References 9 publications

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“…In this work, we demonstrate a novel fabrication process for manufacturing and integrating 3D microactuators on flexible substrates by leveraging benefits from both additive manufacturing and microfabrication. Additive manufacturing, especially at the microscale using two-photon polymerization (TPP) enables direct writing of complex 3D microstructures with high resolution (<100 nm), [24,25] and robust mechanical integration of 3Dprinted microstructures has been achieved with precise alignment capability on rigid silicon wafers [26,27] and even on flexible PET films. [19,28] To achieve electrical integration and to add functionality to 3D-printed structures, metal sputtering processes common in microfabrication have been successfully integrated with TPP to create electrically conductive 3D microstructures and demonstrated 3D microactuators on rigid substrates.…”

Section: Introductionmentioning

confidence: 99%

3D‐Printed Electrostatic Microactuators for Flexible Microsystems

Kim

Kubicek

Bergbreiter

2023

Adv Funct Materials

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Developing small‐scale, lightweight, and flexible devices with integrated microactuators is one of the critical challenges in wearable haptic devices, soft robotics, and microrobotics. In this study, a novel fabrication process that leverages the benefits of 3D printing with two‐photon polymerization and flexible printed circuit boards (FPCBs) is presented. This method enables flexible microsystems with 3D‐printed electrostatic microactuators, which are demonstrated in a flexible integrated micromirror array and a legged microrobot with a mass of 4 mg. 3D electrostatic actuators on FPCBs are robust enough to actuate the micromirrors while the device is deformed, and they are easily integrated with off‐the‐shelf electronics. The crawling robot is one of the lightest legged microrobots actuated without external fields, and the legs actuated with 3D electrostatic actuators enable a locomotion speed of 0.27 body length per second. The proposed fabrication framework opens up a pathway toward a variety of highly integrated flexible microsystems.

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Section: Introductionmentioning

confidence: 99%

3D‐Printed Electrostatic Microactuators for Flexible Microsystems

Kim

Kubicek

Bergbreiter

2023

Adv Funct Materials

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“…Here, it was demonstrated that NiTi bimorph resistor actuators could be actuated with as little as 0.5 V, requiring just 5-15 mA of power, and at rates faster than 1000 times per second (up to 3 kHz) due to the small volume and rapid heat transfer facilitated by large surface to volume ratios. Expanding upon this work even further, these same NiTi films were integrated with nanoscale 3D printing to enable some impressive actuation metrics [36,37]. Specifically, by 3D printing polymeric materials mated with NiTi films, the following metrics were achieved: >5000 reversible actuation cycles with very limited degradation, low voltage actuation of 3.7 V (which is compatible with common Li-ion batteries), large strokes (85 μm for 415 μm length cantilever), and large force-displacement product of 1.2 × 10 −7 N-m, with an impressively small volume and weight (1.04 × 10 −5 cm 3 and 1.27 × 10 −5 g, respectively).…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Characterization of Nanoscale Shape Memory Alloy MEMS Actuators

Knick¹

2020

Advanced Functional Materials

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The miniaturization of engineering devices has created interest in new actua tion methods capable of large displacements and high frequency responses. Shape memory alloy (SMA) thin films have exhibited one of the highest power densities of any material used in these actuation schemes and can thermally recovery strains of up to 10%. Homogenous SMA films can experience reversible shape memory effect, but without some sort of physical biasing mechanism, the effect is only one-way. SMA films mated in a multi-layer stack have the appealing feature of an intrinsic two-way shape memory effect (SME). In this work, we developed a near-equiatomic NiTi magnetron co-sputtering process and characterized shape memory effects. We mated these SMA films in several "bimorph" configurations to induce out of plane curvature in the low-temperature Martensite phase. We quantify the curvature radius vs. temperature on MEMS device structures to elucidate a relationship between residual stress, recovery stress, radius of curvature, and degree of unfolding. We fabricated and tested laser-irradiated and joule heated SMA MEMS actuators to enable rapid actuation of NiTi MEMS devices, demonstrating some of the lowest powers (5-15 mW) and operating fre quencies (1-3 kHz) ever reported for SMA or other thermal actuators.

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“…TPP is capable of high resolution, up to sub-100 nm, and the ability to directly write in 3D space [19], [20]. The high resolution and ability to write directly in 3D spaces has enabled new micro-optical structures [21], [22], 3D mechanical structures [23]- [25], microactuators [26], and microrobots [27]- [32].…”

mentioning

confidence: 99%

A Two-Step Fabrication Method for 3D Printed Microactuators: Characterization and Actuated Mechanisms

Kim

Velez

Pierre

et al. 2020

J. Microelectromech. Syst.

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The fabrication and integration of microactuators with 3D micromechanisms are necessary to develop microrobots with higher capability and complexity. In this work, a twostep fabrication method combining 3D printing with two-photon polymerization (TPP) and aluminum sputtering is demonstrated. Actuators using two different transduction mechanisms (thermal and electrostatic) were fabricated in this process, and a thermal actuator was printed with a mechanism in three-dimensional space without additional assembly steps. This work also provides parameterized characterizations which can be used as design guidelines for building actuators and mechanisms. A design approach to electrically isolate the actuators from the substrate is introduced so that the device can be functional after two fabrication steps without patterning the metal layer. Metal coverage on the sidewalls of trenches are characterized, which provides a design space for deciding electrode gaps and heights in electrostatic actuators. Using these guidelines, 500 µm long thermal actuators showed a maximum displacement of 18.0 µm at 8.31mW and reliably actuated up to 8,500 cycles. An interdigitated electrostatic comb-drive actuator was also successfully demonstrated, displacing 12.7 µm when 160V was applied. Finally, a 3D actuated mechanism was designed by incorporating a thermal actuator with 3D compliant mechanisms to flap 250 µm long wings. Flapping motion was successfully demonstrated.

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Rapid Prototyping of Microactuators by Integrating 3D Printed Polymeric Structures with NiTi Thin Film

Cited by 12 publications

References 9 publications

3D‐Printed Electrostatic Microactuators for Flexible Microsystems

3D‐Printed Electrostatic Microactuators for Flexible Microsystems

Fabrication and Characterization of Nanoscale Shape Memory Alloy MEMS Actuators

A Two-Step Fabrication Method for 3D Printed Microactuators: Characterization and Actuated Mechanisms

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