Microextrusion 3D Printing of Optical Waveguides and Microheaters

The drive for smaller and more compact devices presents several challenges in materials and fabrication strategies. Although photolithography is a well-developed method for creating microdevices, the disparate requirements in fabrication strategies, material choices, equipment and process complexities have limited its applications. Microextrusion printing (μEP) provides a promising alternative for microfabrication. Compared to the traditional techniques, the attractions lie in the wide range of printable material choice, greater design freedom, fewer processing steps, lower cost for customized production, and the plurality of compatible substrates. However, while extrusion-based 3D printing processes have been successfully applied at the macroscale, this seeming simplicity belies the dynamic complexities needed for consistent, repeatable, and cost-effective printing at the microscale. The fundamental understanding of the microextrusion printing process is still lacking. One primary goal of this dissertation, therefore, is to develop the fundamental understanding of μEP. This study elucidates the underlying principles of this printing technique, offering an overall roadmap - stepwise guide for successful printing based on both results in the literature and our experimental tests. The primary motivation is to provide users at both the research and industrial platforms with the requisite knowledge base needed for adapting μEP for microfabrication. Ultimately, this understanding, optimization of materials properties, and process parameters dictate the resolution and quality of the printed features. Following the improved understanding of microextrusion printing, two complementary goals were set. First, in order to test and validate the applicability the framework, a high-resolution microextrusion 3D printer was designed and implemented to enable high precision printing of microdevices and microstructures. Second, taking advantage of the guiding framework and printing platform, printing of novel materials and devices including flexible optics and a high-temperature microheater were explored and demonstrated. One common thread is observed throughout this work, that is, the development of the fundamental understanding of microextrusion 3D printing and its application for creating functional microdevices and structures. This work opens new possibilities and versatile approach for low-cost patterning of materials and functional devices

SOFT , MULTILAYERED ELECTRONICS FOR WEARABLE DEVICES AND METHODS TO PRODUCE THE SAME

Disclosed herein is an efficient fabrication approach to create highly customizable wearable electronics through rapid laser machining and adhesion - controlled soft materials assembly . Well - aligned , multi - layered materials can be created from 2D and 3D elements that stretch and bend while seamlessly integrating with rigid components such as micro chip integrated circuits ( IC ) , discrete electrical components , and interconnects . These techniques are applied using commercially available materials . These materials and methods enable custom wearable electronics while offering versatility in design and functionality for a variety of bio - monitor ing applications

Hand-drawn resistors, capacitors, diodes, and circuits for a pressure sensor system on paper

Hand-written fabrication techniques offer new ways of developing customizable, biodegradable and low-cost electronic systems. In this work, a new level of complexity is demonstrated for hand-written electronics by fabricating passive components, circuits and a sensorsystem on paper. The system comprises a pencil-written graphite force-sensitive-resistor, a pencil-drawn RC-filter, a pen-written half-wave rectifier, and a commercial front-end voltage amplifier. The sensor system exhibits a linear response for pressures up to 1.2 kPa, and a sensitivity of 51 mV kPa-1 . Furthermore, the electrical and mechanical performance of the single components and circuits is studied. Diodes fabricated through pen-written deposition of silver and nickel contacts on amorphous Indium-Gallium-Zinc-Oxide coated paper show rectification ratios up to 1:8. Tensile and compressive bending measurements applied to all pencil-written components for radii down to 0.1 mm indicate minor influence of strain. Similar results are obtained for circuits created from these individual components. Diodes and half-wave rectifiers show a stable behavior when bent to a radius of 5 mm. The presented techniques can enable the development of flexible and eco-friendly wearables and sensors for consumer and healthcare applications, and are an effective way for school-pupils to explore the world of electronics

Development of Open Source Software and Hardware Tool-Chains for Novel Electronics

3-D printing technologies have become widely adopted and have spurred innovation and efficiency across many markets. A large contributor to the success of 3-D printing are open source, low cost electronics. On-site circuit manufacturing, however, has not become as widely utilized as 3-D printing. This project attempts to address this problem by proposing and demonstrating an open source circuit board milling machine which is inexpensive, easily manufactured, and accurate. In three interdependent sub-projects, this thesis defines a standard method for designing open source hardware, the design of the bespoke circuit mill, and explores an application of the mill for novel circuit manufacturing. The first sub-project develops a standardized process for designing, prototyping, and distributing open source hardware. Following these steps can help ensure success for each individual part of the project. In order to validate the procedure, a case study is explored of designing low cost parametric glass slide driers. The second sub-project details the design and construction of a circuit prototyping machine. The open source design procedure is implemented to assure maximum effectiveness. A software interface is also designed to control and carry out processing steps on the milling machine. The mill minimizes lead time and production costs of experimental circuitry. The mill also stands as a strong open source tool that can help foster growth in distributed manufacturing of electronics for a wide array of applications. The third and final sub-project explores a flexible and scalable power monitoring system. The electronics are designed according to the open source design procedure and are manufacturable with the circuit milling machine. The power meter can be used to monitor and log power consumption of a wide range of loads, including both AC and DC

Diseño y control de exoesqueleto robótico para la rehabilitación y asistencia de los movimientos de la mano

Programa de Doctorado en Tecnologías Industriales y de Telecomunicación por la Universidad Miguel Hernández de ElcheHands are one of the main instruments used by humans for interacting with physical environment. Furthermore, hands play an important role in other aspects of daily living such as non-verbal communication or postural control assisted by external supports. Therefore, individuals that suffer some kind of hand impairment become dependent in many common situations, reducing their quality of life. Developments in the field of robotics result in potential solutions to overcome their dependency. In particular, wearable devices such as exoskeletons can help to lessen the impact of the impairment by becoming a new tool for providing more intense and effective rehabilitation therapies, or by their potential applications to assist people during their activities of daily living in a domestic environment. This Doctoral Thesis focuses on the development of a robotic exoskeleton that, due to its constructive features, can be applied to both rehabilitation and assitance environments. As an innovation, this exoskeleton has a new type of force sensor architecture, integrable in the device, favoring the lightness and portability of the equipment and offering a versatile force control interface in a multitude of environments. Along with the force interface, other types of interfaces based on biological and kinematic parameters are studied, in order to provide the system with the necessary versatility to adapt to different user profiles. In addition, two practical applications of the device are presented in complex rehabilitation settings and everyday situations not previously studied. The results of this work are compiled in four publications in journals indexed in the Journal Citation Reports (JCR). The publication Multimodal robotic system for upper-limb rehabilitation in physical environment studies the integration of the hand exoskeleton in a system of robots and sensors that allow the implementation of manipulative therapies in real environments, using a human-machine interface based on electromyographic signals. As an alternative to electromyography for advanced stages of rehabilitation, new interfaces based on motion capture and force feedback are proposed, results are published in the paper Hand exoskeleton for rehabilitation therapies with integrated optical force sensor. A detailed description of the force sensor integrated in the exoskeleton can be found in the publication Customizable optical force sensor for fast prototyping and cost-effective applications. Finally, the publication Exploring new potential applications for Hand Exoskeletons: Power grip to assist human standing studies the applicability of hand exoskeletons to improve postural control

Digital fabrication of custom interactive objects with rich materials

As ubiquitous computing is becoming reality, people interact with an increasing number of computer interfaces embedded in physical objects. Today, interaction with those objects largely relies on integrated touchscreens. In contrast, humans are capable of rich interaction with physical objects and their materials through sensory feedback and dexterous manipulation skills. However, developing physical user interfaces that offer versatile interaction and leverage these capabilities is challenging. It requires novel technologies for prototyping interfaces with custom interactivity that support rich materials of everyday objects. Moreover, such technologies need to be accessible to empower a wide audience of researchers, makers, and users. This thesis investigates digital fabrication as a key technology to address these challenges. It contributes four novel design and fabrication approaches for interactive objects with rich materials. The contributions enable easy, accessible, and versatile design and fabrication of interactive objects with custom stretchability, input and output on complex geometries and diverse materials, tactile output on 3D-object geometries, and capabilities of changing their shape and material properties. Together, the contributions of this thesis advance the fields of digital fabrication, rapid prototyping, and ubiquitous computing towards the bigger goal of exploring interactive objects with rich materials as a new generation of physical interfaces.Computer werden zunehmend in Geräten integriert, mit welchen Menschen im Alltag interagieren. Heutzutage basiert diese Interaktion weitgehend auf Touchscreens. Im Kontrast dazu steht die reichhaltige Interaktion mit physischen Objekten und Materialien durch sensorisches Feedback und geschickte Manipulation. Interfaces zu entwerfen, die diese Fähigkeiten nutzen, ist allerdings problematisch. Hierfür sind Technologien zum Prototyping neuer Interfaces mit benutzerdefinierter Interaktivität und Kompatibilität mit vielfältigen Materialien erforderlich. Zudem sollten solche Technologien zugänglich sein, um ein breites Publikum zu erreichen. Diese Dissertation erforscht die digitale Fabrikation als Schlüsseltechnologie, um diese Probleme zu adressieren. Sie trägt vier neue Design- und Fabrikationsansätze für das Prototyping interaktiver Objekte mit reichhaltigen Materialien bei. Diese ermöglichen einfaches, zugängliches und vielseitiges Design und Fabrikation von interaktiven Objekten mit individueller Dehnbarkeit, Ein- und Ausgabe auf komplexen Geometrien und vielfältigen Materialien, taktiler Ausgabe auf 3D-Objektgeometrien und der Fähigkeit ihre Form und Materialeigenschaften zu ändern. Insgesamt trägt diese Dissertation zum Fortschritt der Bereiche der digitalen Fabrikation, des Rapid Prototyping und des Ubiquitous Computing in Richtung des größeren Ziels, der Exploration interaktiver Objekte mit reichhaltigen Materialien als eine neue Generation von physischen Interfaces, bei

3D PRINTING, OPEN-SOURCE TECHNOLOGY AND THEIR APPLICATIONS IN RESEARCH

Open-source software received tremendous success as it drives down the cost of software and expand the distribution. Open-source hardware, as part of the open-source movement, has just risen into public attention for its potential to further drive down the cost of all kinds of manufacturing goods and reshape the manufacture chain. In this report we explores the history, development and the future of open-source hardware project, summarizing the opportunities, challenges and possible solutions. 3D printing is demonstrated as a booster to assist open-source hardware’s development. Low-cost 3D printer enables at-home and in-time fabrication, the download-print-use-improve-distribute cycle is established to encourage more to make and in turn to benefit more. Researchers, teachers and scientists are the first to receive the benefit since they are often lack of budget to purchase much expensive research tools with only limited function. To demonstrate the power of open-source 3D printing in driving down research cost. A library of 3D printable optics components are designed, printed and tested. The study shows significantly reduced research cost – more than 97% equipment investment is saved with some of the optical parts representing only 1% of the cost of its commercial version. Cost reduction stimulates a much broader participants that can further help in modifying, improving the project or even developing new project, this is how open-source hardware innovation chain is established. In the end it is summarized as the technology advances, printers suitable for all kinds of material such as metals, bio-materials, semiconductors are become feasible, the open-source paradigm has the potential to replace the tradition manufacture and activate the new future

Aerosol-jet-printed, conformable microfluidic force sensors

This is the final version. Available on open access from Cell Press via the DOI in this recordData and code availability: The authors declare that data supporting the findings of this study are available within the article, the Supplemental information, and the DSpace@Cambridge data repository (https://doi.org/10.17863/CAM.63758).Force sensors that are thin, low-cost, flexible, and compatible with commercial microelectronic chips are of great interest for use in biomedical sensing, precision surgery, and robotics. By leveraging a combination of microfluidics and capacitive sensing, we develop a thin, flexible force sensor that is conformable and robust. The sensor consists of a partially filled microfluidic channel made from a deformable material, with the channel overlaying a series of interdigitated electrodes coated with a thin, insulating polymer layer. When a force is applied to the microfluidic channel reservoir, the fluid is displaced along the channel over the electrodes, thus inducing a capacitance change proportional to the applied force. The microfluidic molds themselves are made of low-cost sacrificial materials deposited via aerosol-jet printing, which is also used to print the electrode layer. We envisage a large range of industrial and biomedical applications for this force sensor.European Research Council (ERC)Engineering and Physical Sciences Research Council (EPSRC)Wellcome Trus

A Modular Open-Technology Device to Measure and Adjust Concentration of Sperm Samples for Cryopreservation

Repositories for aquatic germplasm can safeguard the genetic diversity of species of interest to aquaculture, research, and conservation. The development of such repositories is impeded by a lack of standardization both within laboratories and across the research community. Protocols for cryopreservation are often developed ad hoc and without close attention to variables, such as sperm concentration, that strongly affect the success and consistency of cryopreservation. The wide dissemination and use of specialized tools and devices can improve processing reliability, provide data logging, produce custom hardware to address unique problems, and save costs, time, and labor. The goal of the present work was to develop a low-cost and open-technology approach to standardize the concentration of sperm samples prior to cryopreservation. The specific objectives were to: 1) fabricate and test a peristaltic pump and optical evaluation module (POEM); 2) fabricate and test a prototype of the modular, open-technology concentration measurement and adjustment system (CMAS), which incorporated the POEM; 3) identify opportunities to extend the CMAS to microliter volumes through low-cost resin 3-D printing, and 4) identify strategies from this work that can be applied to future open fabrication efforts. The POEM and CMAS were prototyped and tested with biological samples. A relationship between optical signal and cell concentration of channel catfish (Ictalurus punctatus) sperm samples was established by linear regression. In a blind trial, cell concentrations were estimated with the POEM and correlated closely to their known concentrations (linear regression R2 = 0.9945) in a range of 1 × 108 to 4 × 109 cells/mL. The CMAS was able to estimate and adjust the concentration of a sample of the marine microalgae Tetraselmis chuii as a preparatory step for cryopreservation. To explore the possible use of the CMAS with microliter sample volumes in future work, evaluation of low-cost resin 3-D printing showed that this technology can approach conventional microfabrication techniques in feature quality and resolution. The development of the CMAS as open technology can provide opportunities for community-level standardization in cryopreservation of aquatic germplasm, invite new users, makers, and developers into the open-technology community, and increase the reach and capabilities of aquatic germplasm repositories

Aerosol-jet-printed, conformable microfluidic force sensors

This is the final version. Available on open access from Cell Press via the DOI in this recordData and code availability: The authors declare that data supporting the findings of this study are available within the article, the Supplemental information, and the DSpace@Cambridge data repository (https://doi.org/10.17863/CAM.63758).Force sensors that are thin, low-cost, flexible, and compatible with commercial microelectronic chips are of great interest for use in biomedical sensing, precision surgery, and robotics. By leveraging a combination of microfluidics and capacitive sensing, we develop a thin, flexible force sensor that is conformable and robust. The sensor consists of a partially filled microfluidic channel made from a deformable material, with the channel overlaying a series of interdigitated electrodes coated with a thin, insulating polymer layer. When a force is applied to the microfluidic channel reservoir, the fluid is displaced along the channel over the electrodes, thus inducing a capacitance change proportional to the applied force. The microfluidic molds themselves are made of low-cost sacrificial materials deposited via aerosol-jet printing, which is also used to print the electrode layer. We envisage a large range of industrial and biomedical applications for this force sensor.European Research Council (ERC)Engineering and Physical Sciences Research Council (EPSRC)Wellcome Trus