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- Additive manufacturing (8)
- Electrowetting (8)
- 3D printing (3)
- Binder Jetting (3)
- Sintering (3)
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- Contact angle (2)
- Droplet actuator (2)
- Electrochemical diodes (2)
- FDM (2)
- Fluoropolymer (2)
- Laser sintering (2)
- Materials (2)
- Mechanical properties (2)
- Microfluidics (2)
- Nylon 12 (2)
- Polymer sintering (2)
- Printed electronics (2)
- Self assembly (2)
- Stiffness (2)
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- Actuation (1)
- Adhesion (1)
- Aluminum (1)
- Amorphous (1)
- Anodic passivation (1)
- Assemblability (1)
- Assembly (1)
- Assembly theory (1)
- Asymmetry (1)
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Articles 1 - 30 of 33
Full-Text Articles in Mechanical Engineering
Spectral Absorption Coefficient Of Additive Manufacturing Materials, Nicholas J. Wallace, Matthew R. Jones, Nathan B. Crane
Spectral Absorption Coefficient Of Additive Manufacturing Materials, Nicholas J. Wallace, Matthew R. Jones, Nathan B. Crane
Faculty Publications
Active thermography techniques are of interest for quality assurance of additive manufacturing processes. However, accurate measurements of thermophysical properties of materials are required to successfully implement active thermography. In particular, the spectral absorption coefficient of materials commonly used in additive manufacturing must be known to accurately predict the spatial distribution of thermal energy generated from absorption of power emitted by a laser or pulsed flash lamp. Accurate measurements of these optical properties are also needed to develop greater understanding of additive manufacturing processes that rely on radiative heat transfer to fuse powders. This paper presents spectral absorption coefficient measurements and …
Impact Of Sintering Time And Temperature On Mechanical Properties In Projection Sintering Of Polyamide-12, Justin Nussbaum, Taranjot Kaur, Julie Harmon, Nathan B. Crane
Impact Of Sintering Time And Temperature On Mechanical Properties In Projection Sintering Of Polyamide-12, Justin Nussbaum, Taranjot Kaur, Julie Harmon, Nathan B. Crane
Faculty Publications
In powder bed fusion additive manufacturing (AM), the fusing process is temperature and time dependent. However, little work has been done to understand how different processing temperatures and times might impact the mechanical properties at longer sintering times than are typical in laser sintering (LS) systems. Prior results with projection sintering have shown that heating for longer times (>1s) improves part toughness compared to laser sintering. In this work, Large Area Projection Sintering (LAPS) is used to sinter entire layers of material simultaneously over the course of a few seconds with spatial control of layer temperature. This work evaluates …
Impact Of Part Thickness And Drying Conditions On Saturation Limits In Binder Jet Additive Manufacturing, Nathan B. Crane
Impact Of Part Thickness And Drying Conditions On Saturation Limits In Binder Jet Additive Manufacturing, Nathan B. Crane
Faculty Publications
Binder jetting (BJ) is a high build-rate additive manufacturing process with growing commercial interest. Growth in BJ applications is driven by the use of finer powders and improved post-processing methods that can produce dense, homogenous final parts. However, understanding of the basic droplet/powder interaction is relatively limited. This paper considers the impact of in-process drying, part geometry, and droplet size on a key printing parameter: binder saturation. Parts of varying thicknesses are printed with a range of saturation levels under various heating conditions. The ratio of the printed part mass to the theoretical part mass is used to detect bleeding. …
Influence Of Droplet Velocity, Spacing, And Inter-Arrival Time On Line Formation And Saturation In Binder Jet Additive Manufacturing, Trenton Colton, Nathan B. Crane
Influence Of Droplet Velocity, Spacing, And Inter-Arrival Time On Line Formation And Saturation In Binder Jet Additive Manufacturing, Trenton Colton, Nathan B. Crane
Faculty Publications
Binder Jetting (BJ) is a low-cost Additive Manufacturing (AM) process that uses inkjet technology to selectively bind particles in a powder bed. BJ relies on the ability to control, not only the placement of binder on the surface but also its imbibition into the powder bed. This is a complex process in which picoliter-sized droplets impact powder beds at velocities of 1-10 m/s. However, the effects of printing parameters such as droplet velocity, size, spacing, and inter-arrival time on saturation level (fraction of pore space filled with binder) and line formation (merging of droplets to form a line) are unknown. …
Adhesion Testing Of Printed Inks While Varying The Surface Treatment Of Polymer Substrates, Clayton Neff, Edwin Elston, Amanda Schrand, Nathan B. Crane
Adhesion Testing Of Printed Inks While Varying The Surface Treatment Of Polymer Substrates, Clayton Neff, Edwin Elston, Amanda Schrand, Nathan B. Crane
Faculty Publications
Additive manufacturing with conductive materials enables new approaches to printed electronics that are unachievable by standard electronics manufacturing processes. In particular, electronics can be embedded directly into structural components in nearly arbitrary 3D space. While these methods incorporate many of the same materials, the new processing methods require standard test methods to compare materials, processing conditions, and determine design limits. This work demonstrates a test method to quantitatively measure the adhesion failure of printed inks deposited on a substrate without changing the ink printing conditions. The proposed method is an adaption of single lap shear testing in which the lap …
Mechanical And Temperature Resilience Of Multi-Material Systems For Printed Electronics Packaging, Clayton Neff, Justin Nussbaum, Chris Gardiner, Nathan B. Crane, James L. Zunino, Mike Newton
Mechanical And Temperature Resilience Of Multi-Material Systems For Printed Electronics Packaging, Clayton Neff, Justin Nussbaum, Chris Gardiner, Nathan B. Crane, James L. Zunino, Mike Newton
Faculty Publications
In this work, two AM technologies were utilized to compare the effectiveness of fabricating a simple electronic device with a conductive trace and hollow cylinder representative of ‘printed packaging’ that would survive harsh environmental conditions. The printed packaging cylinder delineates printed potting for electronics packaging. An nScrypt direct write (DW) system was the primary manufacturing system but a developing technology—coined large area projection sintering (LAPS)—manufactured a subset of samples for comparison. The tests follow Military Standard (MIL STD) 883K and include resiliency evaluation for die shear strength, temperature cycling, thermal shock, and high G loading by mechanical shock. Results indicate …
Wetting Metamorphosis Of Hydrophobic Fluoropolymer Coatings Submerged In Water And Ultrasonically Vibrated, Matthew Trapuzzano, Nathan B. Crane, Rasim Guldiken, Andrés Tejada-Martínez
Wetting Metamorphosis Of Hydrophobic Fluoropolymer Coatings Submerged In Water And Ultrasonically Vibrated, Matthew Trapuzzano, Nathan B. Crane, Rasim Guldiken, Andrés Tejada-Martínez
Faculty Publications
Many important processes, from manufacture of integrated circuit boards, to an insect’s ability to walk on water, depend on the wetting of liquids on surfaces. Wetting is commonly controlled through material selection, coatings, and/or surface texture. However, wetting is sensitive to environmental conditions. In particular, some hydrophobic fluoropolymer coatings are sensitive to extended water exposure as evidenced by a declining contact angle and increasing contact angle hysteresis. Understanding “degradation” of these coatings is critical to applications that employ them. The durability of a series of fluoropolymer coatings were tested by measuring the contact angle before, during, and after extended submersion …
Binder Jetting: A Review Of Process, Materials, And Methods, Mohsen Ziaee, Nathan B. Crane
Binder Jetting: A Review Of Process, Materials, And Methods, Mohsen Ziaee, Nathan B. Crane
Faculty Publications
Binder Jet printing is an additive manufacturing technique that dispenses liquid binding agent on powder. Layers are formed repeatedly to build up a physical article. Binder jetting (BJ) can be adapted to almost any powder with high production rates. The BJ process utilizes a broad range of technologies including printing methods, powder deposition, dynamic binder/powder interaction, and post-processing methods. A wide variety of materials have been demonstrated including polymers, metals, and ceramics, but a common challenge is developing printing and post-processing methods that maximize part performance. This article presents a broad review of technologies and approaches that have been applied …
Impact Of Pulse Length On The Accuracy Of Defect Depth Measurements In Pulse Thermography, James Pierce, Nathan B. Crane
Impact Of Pulse Length On The Accuracy Of Defect Depth Measurements In Pulse Thermography, James Pierce, Nathan B. Crane
Faculty Publications
Pulse thermography is a nondestructive testing method in which an energy pulse is applied to a surface while the surface temperature evolution is measured to detect sub surface defects and estimate their depth. This nondestructive test method was developed on the assumption of instantaneous surface heating, but recent work has shown that relatively long pulses can be used to accurately determine defect depth in polymers. This paper examines the impact of varying input pulse length on the accuracy of defect depth quantification as a function of the material properties. Simulations using both thermoplastics and metals show that measurement error is …
Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes, Garrett Craft, Justin Nussbaum, Nathan B. Crane, J. P. Harmon
Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes, Garrett Craft, Justin Nussbaum, Nathan B. Crane, J. P. Harmon
Faculty Publications
Additive Manufacturing provides many advantages in reduced lead times and increased geometric freedom compared to traditional manufacturing methods, but material properties are often reduced. This paper considers powder bed fusion of polyamide 12 (PA12, Nylon 12) produced by three different processes: laser sintering (LS), multijet fusion (MJF)/high speed sintering (HSS), and large area projection sintering (LAPS). While all utilize similar PA12 materials, they are found to differ significantly in mechanical properties especially in elongation to break. The slower heating methods (MJF/HSS and LAPS) produce large elongation at break with the LAPS process showing 10x elongation and MJF/HSS exhibiting 2.5x the …
Experimental And Theoretical Investigation Of Mechanical Response Of Laser-Sintered Diamond Lattice Structures, Clayton Neff, Neil Hopkinson, Nathan B. Crane
Experimental And Theoretical Investigation Of Mechanical Response Of Laser-Sintered Diamond Lattice Structures, Clayton Neff, Neil Hopkinson, Nathan B. Crane
Faculty Publications
Typically additive manufacturing (AM) processes are limited to a single material per part while many products benefit from the integration of multiple materials with varied properties. To achieve the benefits of multiple materials, the geometric freedom of AM could be used to build internal structures that emulate a range of different material properties such as stiffness, Poisson’s ratio, and elastic limit using only one build material. This paper examines the range of properties that can be simulated using diamond lattice structures manufactured from Nylon 12 with a commercial laser sintering process. Diamond lattices were fabricated with a unit cell length …
Design For Maintainability In Developing Communities—A Case Study On The Uros Islands, Thomas Barlow
Design For Maintainability In Developing Communities—A Case Study On The Uros Islands, Thomas Barlow
Undergraduate Honors Theses
Designing products for developing communities has exposed many of the underlying assumptions that engineers from developed nations have during the design process. There has been much written about these underlying assumptions in order to create a better framework for designing for developing communities. One unexplored, yet important area is the universality of common maintainability principles used in developed countries when designing products used in developing communities. Such principles include: simplicity, diagnosability, standardization of parts, modular subassemblies, minimizing assembly and disassembly parts, labeling components, increased life of moving parts, manuals, and simplifying tools needed for repairs [1]–[3]. The purpose of this …
Evaluation Of Processing Variables In Polymer Projection Sintering, Justin Nussbaum, Nathan B. Crane
Evaluation Of Processing Variables In Polymer Projection Sintering, Justin Nussbaum, Nathan B. Crane
Faculty Publications
Purpose – Projection sintering, a system for selectively sintering large areas of polymer powder simultaneously with a high power projector is introduced. The paper evaluates the suitability of laser sintering process parameters for projection sintering as it uses substantially lower intensities, longer exposure times, and larger areas than conventional laser sintering (LS).
Design/methodology/approach – The tradeoffs in sintering outcomes are evaluated by creating single layer components with varied exposure times and optical intensities. Some of these components were cross-sectioned and evaluated for degree of densification while the single layer thickness and the maximum tensile force was measured for the rest. …
Impact Of Vapor Polishing On Surface Quality And Mechanical Properties Of Extruded Abs, Clayton Neff, Matthew Trapuzzano, Nathan B. Crane
Impact Of Vapor Polishing On Surface Quality And Mechanical Properties Of Extruded Abs, Clayton Neff, Matthew Trapuzzano, Nathan B. Crane
Faculty Publications
Purpose — Additive manufacturing (AM) is readily capable of producing models and prototypes of complex geometry and is advancing in creating functional parts. However, AM processes typically underperform traditional manufacturing methods in mechanical properties, surface roughness, and hermeticity. Solvent vapor treatments (vapor polishing) are commonly used to improve surface quality in thermoplastic parts, but the results are poorly characterized.
Design/methodology/approach — This work quantifies the surface roughness change and also evaluates the effect on hermeticity and mechanical property impacts for “as-printed” and acetone vapor-polished ABS tensile specimens of 1, 2, and 4 mm thicknesses produced by material extrusion (FDM).
Findings …
Controlling Normal Stiffness In Droplet-Based Linear Bearings, Qi Ni, Nathan B. Crane
Controlling Normal Stiffness In Droplet-Based Linear Bearings, Qi Ni, Nathan B. Crane
Faculty Publications
While Capillary forces are negligible relative to gravity at the macroscale, they provide adequate force to effectively manipulate millimeter to micro meter objects. The fluidic actuation can be accomplished using droplets that also act as bearings. While rotary droplet bearings have been previously demonstrated, this paper considers the performance potential of discrete droplets acting as linear bearings. Specifically, it addresses the positioning accuracy of a droplet-based bearing consisting of a droplet between a moving plate and a stationary substrate with constrained wetting region under a normal load using both closed form analytical solutions and numerical simulations. The vertical force and …
Surface Acoustic Wave Based Pumping In A Microchannel, Tao Wang, Qi Ni, Nathan B. Crane, Rasim Guldiken
Surface Acoustic Wave Based Pumping In A Microchannel, Tao Wang, Qi Ni, Nathan B. Crane, Rasim Guldiken
Faculty Publications
Pumping and manipulation of liquids in microfluidic channels is important for many mechanical, chemical and biomedical applications. Surface acoustic wave based devices fabricated on high-efficiency piezoelectric substrates have been recently investigated for mixing and separation application within microfluidic channels. In this paper, we introduce a novel integrated surface acoustic wave based pump for liquid delivery and precise manipulation within a microchannel. The device employs a hydrophobic surface coating (Cytop) in the device design for decreasing the friction force and increasing the bonding. Contrary to previous surface acoustic wave based pump, this device does not need precise layers of water and …
Binder-Jet Printing Of Fine Stainless Steel Powder With Varied Final Density, Mohsen Ziaee, Eric M. Tridas, Nathan B. Crane
Binder-Jet Printing Of Fine Stainless Steel Powder With Varied Final Density, Mohsen Ziaee, Eric M. Tridas, Nathan B. Crane
Faculty Publications
Binder jetting is an additive manufacturing process that produces relatively weak porous parts that are strengthened through sintering and/or infiltration. This paper reports on two different methods of preparing fine 316 stainless steel powder and their impact on the final sintered density and dimensions relative to direct printing into -22 micron powder. The first method uses agglomerates of fine powder. In the second, nylon 12 powders are mixed with the steel powder as a fugitive space holder to increase porosity. Sintered density and sintering shrinkage of agglomerate material are shown to vary with the density of the spread powder bed. …
Skin Strain Measurement To Predict Knee Joint Angles Through Nanocomposite Stain Gauges, Adin Martineau, James Tracy, Gavin Collins, Parker Rosquist, Dustin A. Bruening, Matt K. Seeley, David T. Fullwood, Anton E. Bowden
Skin Strain Measurement To Predict Knee Joint Angles Through Nanocomposite Stain Gauges, Adin Martineau, James Tracy, Gavin Collins, Parker Rosquist, Dustin A. Bruening, Matt K. Seeley, David T. Fullwood, Anton E. Bowden
Biomedical Engineering Western Regional Conference
Explores the possibility of using high deflection nanocomposite strain gauges as knee joint angle sensor.
Redesign Of Computer Keyboards For Hospital And Consumer Use, Kent Williams, Brian Jensen, Anton Bowden
Redesign Of Computer Keyboards For Hospital And Consumer Use, Kent Williams, Brian Jensen, Anton Bowden
Biomedical Engineering Western Regional Conference
Application of carbon nanotube coatings to computer keyboards in order to reduce the spread of bacteria in hospitals and homes.
Keywords: carbon nanotube, bacteria, antimicrobial, keyboard, design, MRSA, biofilm
A Nanocomposite Sensor Neck Sleeve For Tracking In Vivo Spine Kinematics In The Alpaca, Colton Porter Graham, Anton Bowden
A Nanocomposite Sensor Neck Sleeve For Tracking In Vivo Spine Kinematics In The Alpaca, Colton Porter Graham, Anton Bowden
Biomedical Engineering Western Regional Conference
Chronic low back pain in the US is often attributed to intervertebral disc degeneration. Camelids, particularly alpacas, pose a potential model for spinal treatment due to similarity of the spinal structure and vertical loading. Alpacas also exhibit a high rate of natural disc degeneration. To gain more understanding about how disc degeneration is caused in alpacas it is necessary to understand the loading and motion of the alpaca cervical spine. The goal of the present work was to incorporate nanocomposite sensors into a custom-designed neck sleeve to track the daily in-vivo neck motion of an alpaca in its natural environment.
Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane
Controlled Manipulation Of Floating Objects On Deformed Fluid Interfaces And Conditions For Stable Equilibria, Jose M. Carballo, Qi Ni, Jose Vasquez, Nathan B. Crane
Faculty Publications
At the millimeter scale, interactions between floating and semi-immersed objects are significant. The local curvature of the interface is modified by the weight/buoyancy forces of floating objects, and by the surface properties of semi-immersed objects. The curvature changes generate attractive (or repulsive) interactions between floating parts, and semi-immersed objects. This work demonstrates how electrowetting can manipulate these interactions in order to position, align, assemble and transport parts attached to the fluid interface. This demonstrates one way in which fluid interfaces can provide an alternative to standard pick and place technology for part positioning/assembly. Typically, the part/rod forces are purely attractive …
Open-Loop Electrowetting Actuation With Micro-Stepping, Qi Ni, Daniel E. Capecci, Nathan B. Crane
Open-Loop Electrowetting Actuation With Micro-Stepping, Qi Ni, Daniel E. Capecci, Nathan B. Crane
Faculty Publications
Microfluidic-driven mechanical actuation opens new possibilities for positioning and manipulating delicate small components. However, existing microfluidic actuation methods are not well-suited to positioning with high resolution. This paper reports a method for precise, open-loop control of droplet position in finite steps by varying the duty cycle of the input signal in electrowetting actuation. When wetted to a solid object, both the droplet and the solid can be actuated. Unlike conventional electrowetting actuation methods, positioning resolution in our proposed method can be much smaller than the size of the underlying electrodes without requiring closed loop feedback control system. Using a leaky …
Robust Bi-Directional Continuous Electrowetting Based On Metal-Semiconductor (M-S) Diodes, Qi Ni, Daniel E. Capecci, Millicent Schlafly, Nathan B. Crane
Robust Bi-Directional Continuous Electrowetting Based On Metal-Semiconductor (M-S) Diodes, Qi Ni, Daniel E. Capecci, Millicent Schlafly, Nathan B. Crane
Faculty Publications
We demonstrate bi-directional continuous electrowetting by embedding metal-semiconductor diodes in the electrowetting substrate. Unlike conventional electrowetting on dielectric (EWOD), bi-directional continuous electrowetting uses a single electrode pair to actuate a droplet through long distances. As long as the voltage potential is maintained between two end electrodes, the droplet moves toward the electrode with the higher potential. However, previously reported material systems had limited success in repeated actuation. In this work, diodes based on Schottky barriers were fabricated by forming metal-semiconductor junctions between titanium and high resistivity n-type silicon. The performance enhancements were evaluated using current-voltage measurements of interface pairs. When …
Stress-Limiting Test Structures For Rapid Low-Cost Strength And Stiffness Assessment, Andrew Katz, Craig P. Lusk, Nathan B. Crane
Stress-Limiting Test Structures For Rapid Low-Cost Strength And Stiffness Assessment, Andrew Katz, Craig P. Lusk, Nathan B. Crane
Faculty Publications
Purpose: Evaluate the use of a simple printed geometry to estimate mechanical properties (elastic modulus, yield strength) with inexpensive test equipment.
Design Methodology/Approach: Test geometry is presented that enables controlled strains with manual deformation and repeatable measurement of vibrational frequencies. This is tested with multiple FDM machines to assess measurement accuracy and repeatability. Printing orientation and some printing parameters are varied to assess the measurement sensitivity.
Findings: The test methods show good correlation with manufacturer material specifications in the X-Y plane and reported elastic strain limits. It is also sensitive to printing orientation and printing parameters.
Research Limitations/Implications: Further work …
Electrowetting Force And Velocity Dependence On Fluid Surface Energy, Qi Ni, Daniel E. Capecci, Nathan B. Crane
Electrowetting Force And Velocity Dependence On Fluid Surface Energy, Qi Ni, Daniel E. Capecci, Nathan B. Crane
Faculty Publications
Electrowetting on Dielectric is a phenomenon in which the shape and apparent contact angle of a droplet changes when an electric field is applied across the droplet interface. If the field is asymmetric with respect to the droplet, then a net force can be applied to the droplet. In this work, we have measured the electrowetting force by confining the droplet shape beneath a glass plate and measuring the force on the plate. The force was measured as a function of voltage for a range of fluids with different surface energy. Measured forces show excellent agreement with predictions based on …
Long Life Electrochemical Diodes For Continuous Electrowetting, Mehdi Khodayari, Ben Hahne, Nathan B. Crane
Long Life Electrochemical Diodes For Continuous Electrowetting, Mehdi Khodayari, Ben Hahne, Nathan B. Crane
Faculty Publications
The rate of electrochemical reactions in some systems varies with the polarity of the overpotential on the working electrode, introducing diode-like behavior at the electrode/electrolyte interface. However, with repeated bipolar cycling, the electrochemical current damages the electrodes. We have connected electrochemical diodes in series with opposing polarities to reduce the diode current while charging a capacitive circuit. We have previously used this capacitive circuit arrangement to actuate aqueous droplets continuously using the electrowetting (EW) effect. In this study, the performance of electrochemical diodes under repeated voltage cycles is investigated. Aluminum and titanium electrodes in contact with three electrolyte solutions (0.1 …
Floating Electrode Electrowetting On Hydrophobic Dielectric With An Sio2 Layer, Mehdi Khodayari, Benjamin Hahne, Nathan B. Crane, Alex A. Volinsky
Floating Electrode Electrowetting On Hydrophobic Dielectric With An Sio2 Layer, Mehdi Khodayari, Benjamin Hahne, Nathan B. Crane, Alex A. Volinsky
Faculty Publications
Floating electrode electrowetting is caused by dc voltage applied to a liquid droplet on the Cytop surface, without electrical connection to the substrate. The effect is caused by the charge separation in the floating electrode. A highly-resistive thermally-grown SiO2 layer underneath the Cytop enables the droplet to hold charges without leakage, which is the key contribution. Electrowetting with an SiO2 layer shows a memory effect, where the wetting angle stays the same after the auxiliary electrode is removed from the droplet in both conventional and floating electrode electrowetting. Floating electrode electrowetting provides an alternative configuration for developing advanced electrowetting-based devices.
Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky
Electrochemical Explanation For Asymmetric Electrowetting Response, Mehdi Khodayari, Nathan B. Crane, Alex A. Volinsky
Faculty Publications
In electrowetting, a droplet/substrate contact angle is modulated by applying a potential difference between the droplet and the substrate. Typically, the droplet potential is changed via an auxiliary electrode dipped in the droplet. Here, it is shown that electrochemical reactions lead to a potential drop on the auxiliary electrode in electrowetting, which degrades the droplet contact angle modulation. The magnitude of this effect depends on the voltage polarity. This problem can be addressed by using a dielectric layer, such as SiO2, which can prevent electrochemical reactions with the electrowetting substrate and the auxiliary electrode.
A Material System For Reliable Low Voltage Anodic Electrowetting, Mehdi Khodayari, Jose Carballo, Nathan B. Crane
A Material System For Reliable Low Voltage Anodic Electrowetting, Mehdi Khodayari, Jose Carballo, Nathan B. Crane
Faculty Publications
Electrowetting on dielectric is demonstrated with a thin spin-coated fluoropolymer over an aluminum electrode. Previous efforts to use thin spin-coated dielectric layers for electrowetting have shown limited success due to defects in the layers. However, when used with a citric acid electrolyte and anodic voltages, repeatable droplet actuation is achieved for 5000 cycles with an actuation of just 10 V. This offers the potential for low voltage electrowetting systems that can be manufactured with a simple low-cost process.
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Fluidic Assembly At The Microscale: Progress And Prospects, Nathan B. Crane, Onursal Onen, Jose Carballo, Qi Ni, Rasim Guldiken
Faculty Publications
Assembly permits the integration of different materials and manufacturing processes to increase system functionality. It is an essential step in the fabrication of useful systems across size scales from buildings to molecules. However, at the microscale, traditional “grasp and release” assembly methods and chemically inspired self-assembly processes are less effective due to many scaling effects. Many methods have been developed for improving microscale assembly. Often these methods include fluidic forces or the use a fluidic medium in order to enhance their performance. This paper reviews basic assembly theory and modeling methods. Three basic assembly strategies (tool-directed, process-directed, and part-directed) are …