Globally distributed additive manufacturing is a relatively new frontier in the field of product lifecycle management. Designers are independent of additive manufacturing services, often thousands of miles apart. Manufacturing data must be transmitted electronically from designer to manufacturer to realize the benefits of such a system. Unalterable blockchain legers can record transactions between customers, designers, and manufacturers allowing each to trust the other two without needing to be familiar with each other. Although trust can be established, malicious printers or customers still have the incentive to produce unauthorized or pirated parts. To prevent this, machine instructions are encrypted and electronically transmitted to the printing service, where an authorized printer decrypts the data and prints an approved number of parts or products. The encrypted data may include G-Code machine instructions which contain every motion of every motor on a 3D printer. Once these instructions are decrypted, motor drivers send control signals along wires to the printer's stepper motors. The transmission along these wires is no longer encrypted. If the signals along the wires are read, the motion of the motor can be analyzed, and G-Code can be reverse engineered. This thesis demonstrates such a threat through a simulated attack on a G-Code controlled device. A computer running a numeric controller and G-Code interpreter is connected to standard stepper motors. As G-Code commands are delivered, the magnetic field generated by the transmitted signals is read by a Hall Effect sensor. The rapid oscillation of the magnetic field corresponds to the stepper motor control signals which rhythmically move the motor. The oscillating signals are recorded by a high speed analog to digital converter attached to a second computer. The two systems are completely electronically isolated. The recorded signals are saved as a string of voltage data with a matching time stamp. The voltage data is processed through a Matlab script which analyzes the direction the motor spins and the number of steps the motor takes. With these two pieces of data, the G-Code instructions which produced the motion can be recreated. The demonstration shows the exposure of previously encrypted data, allowing for the unauthorized production of parts, revealing a security flaw in a distributed additive manufacturing environment. / Master of Science / Developed at the end of the 20th century, additive manufacturing, sometimes known as 3D printing, is a relatively new method for the production of physical products. Typically, these have been limited to plastics and a small number of metals. Recently, advances in additive manufacturing technology have allowed an increasing number of industrial and consumer products to be produced on demand. A worldwide industry of additive manufacturing has opened up where product designers and 3D printer operators can work together to deliver products to customers faster and more efficiently. Designers and printers may be on opposite sides of the world, but a customer can go to a local printer and order a part designed by an engineer thousands of miles away. The customer receives a part in as little time as it takes to physically produce the object. To achieve this, the printer needs manufacturing information such as object dimensions, material parameters, and machine settings from the designer. The designer risks unauthorized use and the loss of intellectual property if the manufacturing information is exposed. Legal protections on intellectual property only go so far, especially across borders. Technical solutions can help protect valuable IP. In such an industry, essential data may be digitally encrypted for secure transmission around the world. This information may only be read by authorized printers and printing services and is never saved or read by an outside person or computer. The control computers which read the data also control the physical operation of the printer. Most commonly, electric motors are used to move the machine to produce the physical object. These are most often stepper motors which are connected by wires to the controlling computers and move in a predictable rhythmic fashion. The signals transmitted through the wires generate a magnetic field, which can be detected and recorded. The pattern of the magnetic field matches the steps of the motors. Each step can be counted, and the path of the motors can be precisely traced. The path reveals the shape of the object and the encrypted manufacturing instructions used by the printer. This thesis demonstrates the tracking of motors and creation of encrypted machine code in a simulated 3D printing environment, revealing a potential security flaw in a distributed manufacturing system.

The inability to monitor the molecular trajectories of whole organs throughout the clinically relevant ischemic interval is a critical problem underlying the organ shortage crisis. Here, we report a novel technique for fabricating manufacturing conformal microfluidic devices for organ interface. 3D conformal printing was leveraged to engineer and fabricate novel organ-conforming microfluidic devices that endow the interface between microfluidic channels and the organ cortex. Large animal studies reveal microfluidic biopsy samples contain rich diagnostic information, including clinically relevant biomarkers of ischemic pathophysiology. Overall, these results suggest microfluidic biopsy via 3D printed organ-conforming microfluidic devices could shift the paradigm for whole organ preservation and assessment, thereby relieving the organ shortage crisis through increased availability and quality of donor organs. / Master of Science / Organ failure is one of the most common cause of morbidity and mortality in humans. Unfortunately, there are not enough donor organs to meet the present demand, often referred to as the organ shortage crisis. To compound the problem, there is lack of understanding of the biological processes occurring in organs during the transplantation interval. Here, we present a method to manufacture a biomedical device using a 3D printing technique to monitor, collect, and isolate diagnostically relevant biological species released during the transplantation interval. This information has the potential to lead to a better understanding of organ health, which ultimately could increase the availability and quality of donor organs.

In recent years, there has been a significant amount of research into cellulose nanocrystals (CNCs). These materials are categorized as being between 5 and 10 nm wide and being 100-250 nm long. CNCs have several uses, but the most common is the reinforcement of polymer composites. Here I present 2 papers investigating CNC-based composites. By using standard bleaching procedures, pure cellulose was isolated from pistachio shells. Sulfuric acid was used to isolate cellulose nanocrystals from the purified cellulose. The obtained crystals were investigated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The CNCs were also added to thermoplastic polyurethane (TPU) to observe the reinforcement effects by dynamic mechanical analysis. Pistachio shells offered a high yield source material for CNCs, with a high aspect ratio but a low crystallinity. They did offer significant reinforcement of the TPU, but less than the commercially available wood-based CNCs. Wood-based CNCs were also mixed with TPU in structured composites to create a film which actuates when exposed to water. The method of actuation is based on the different amounts of absorption of water in the composite as opposed to the pure TPU. The actuation was modeled based on the absorption of water and the modulus of two components. Mechanical properties of the CNC/TPU composites were evaluated via dynamic mechanical analysis, and water absorption was measured gravimetricaly. The tests helped us to evaluate our model which we compared to the composites. / Master of Science / Composites are a category of materials where two or more materials are used together to enhance each of their strengths. Such materials are often used in airplanes, spacecraft, sporting equipment, and many high-end products. Cellulose nanocrystals (CNCs) have been research with the goal of improving the environmental sustainability and performance of composite materials. This newly utilized material is found in plants and some animals to provide them with their strength. Researches have already shown that CNCs can improve the performance of many materials while reducing their lifetime environmental impact. In order to increase the market for CNCs, we are looking at cost-reducing methods of producing them as well as finding exciting new uses for them once they are made. Right now, most CNCs are isolated from wood or cotton, which already have existing markets. This thesis presents a method of using pistachio shells, which are a waste product in many parts of the world including the United States. By finding new sources of CNCs, we hope to add to the body of knowledge and reduce the price of CNC production. This thesis also lays the groundwork for a material that changes shape when exposed to water. By integrating CNCs into only part of a polymer, when water is added, the part with the CNCs will increase in size, causing it to push on the polymer. Our hope is to create a new use for CNC composites to help to increase the market for them. We discuss potential methods and proofs of concept on how to create a 3D-printed part using CNCs and polyurethane.

This master's thesis deals with the challenges of undesirable thermal expansion in lightweight materials. Thermal expansion of parts or components can lead to malfunction or breakdowns of complete systems in demanding environment where a large temperature gradient often exists. This work investigates a class of lightweight materials of which the thermal expansion coefficient can be controlled. Moreover, an additive manufacturing approach to produce these thermal management materials with high fidelity and reliability are critical to reach this goal. To achieve these two major research objectives analytic predictions, simulations, and measurement of thermal expansion coefficient with respect to temperature changes are conducted. Design and optimization of a high precision multi-material manufacturing apparatus has been conducted, leading to significant increase in production quality including reliability, efficiency, and costs. / Master of Science / This master’s thesis deals with the challenges of undesirable thermal expansion in lightweight materials. Under thermal load parts or components usually expand and this can lead to malfunction or breakdowns. To encounter this issue of the undesired expansion this work investigates a class of lightweight materials of which the thermal expansion coefficient can be controlled. Moreover, an additive manufacturing approach to produce these thermal management materials with high fidelity and reliability are critical to reach this goal. To achieve these two major research objectives analytic predictions, simulations, and measurement of thermal expansion coefficient with respect to temperature changes are conducted. Design and optimization of a high precision multi-material manufacturing apparatus has been conducted, leading to significant increase in production quality including reliability, efficiency, and costs.

This study explores the application, benefits, and challenges associated with the implementation of Slippery Liquid-Infused Porous Surfaces (SLIPS) technology with additive manufacturing, with a particular focus on healthcare highlighting its potential to enhance the performance and safety of medical devices and implants by preventing biofouling and bacterial colonization. Challenges in the complex process of manufacturing implantable devices, requiring specialized equipment and expertise, present a significant barrier to widespread use, particularly in resource-limited settings. These delicate implants are then used to perform regenerative, therapeutic, and diagnostic functionalities in patients, significantly advancing the healthcare practice. On the other hand, most of these implants experience the biofouling issue caused by a complex of bacteria and protein on the surface of the implants during operation. In this study, we developed a durable yet practical antifouling strategy by integrating SLIPS coating technique – a bioinspired ultra-repellent surface – with an advanced additive manufacturing technique. SLIPS technology utilizes a mechanism where a stable, immiscible lubricant layer is infused into a porous or textured solid substrates. The embedded lubricant layer is specifically designed to be immiscible with other liquids, preventing liquids from wetting the SLIPS-treated surface and allowing them to simply glide off. The lubricant's creation of a liquid-liquid interface, which greatly lowers adhesion and friction between the surface and any touching materials, is what causes this effect. Integrating SLIPS with 3D printing technology enables the creation of a complex, customizable surface with enhanced antifouling and self-cleaning properties. 3D structures were printed using after meticulous designing process and printing parameters so that the designs had a 200-300µm of pore size and could give a capillary wicking action. This process can streamline the overall process by providing rapid prototyping, design flexibility, customization and personalization, and integration of complex features. The fabrication process of this involves chemical vapour deposition of Trichloro (1H, 1H, 2H, 2H – Perfluorooctyl), which is a fluorinated silane compound, making the surface molecule hydrophobic and oleophobic and immersing the silanized devices into Perflourodecalin (PFD). The PFD often used in healthcare industry, acts as the lubricant layer and forms SLIPS. Our approach to characterize the SLIPS-modified samples involved testing the samples for the sliding angle defined as minimum angle of inclination at which a droplet on the surface begins to move or slide off serving as a critical measure of the surface’s repellency and effectiveness in minimizing adhesion. To further quantify our study, we inoculated the samples with S.aureus bacterium for 1, 2, 5, and 7 days and analysed them for the formation of biolfilm. Our study successfully integrates the SLIPS technology into additive manufacturing and validates the claims of SLIPS technology for its antiadhesive and antifouling properties. Additionally, long-term durability and the performance of SLIPS in real-world applications are areas of active research, with the stability and longevity of the lubricant layer being critical for maintaining its unique properties over time alongside the need for periodic maintenance. In healthcare, the biocompatibility and safety of the lubricants used in SLIPS coatings are paramount, demanding thorough testing to ensure patient safety and regulatory compliance. Moreover, the mechanical durability and resistance to wear of SLIPS coatings are crucial for their sustained effectiveness in medical applications. This study emphasizes the need for collaborative research, clinical trials, and regulatory dialogue to overcome these challenges and fully realize the potential of SLIPS technology in 3D printed implants improving medical device performance and patient safety.

This thesis constitutes the final part of studies for a Bachelor’s degree in Mechanical Engineering. The report presents an investigation of radar-absorbing materials with a focus on the effects of magnetic layers in 3D-printed materials. This work is conducted at the Swedish Defence Research Agency (FOI), a leading entity in defense and security research in Europe. The project aims to improve the understanding of radar-absorbing materials and develop techniques to reduce the signature when exposed to radar. The purpose of the work includes analyzing different material compositions to identify the one that minimizes radar reflection and exploring gradient effects with multiple layers at the bottom and fewer at the top of the material. Additionally, the study aims to develop a mathematical model to describe the dependency of permittivity or loss tangent on the number of PLA-M layers compared to the base material PLA from the 3D printer. The method used in the project is derived from ”Product Design and Development” [1] with some adjustments. The work began with an extensive preliminary study that combined both theoretical and practical elements. A literature review and microscopic analyses of 3D-printed samples in PLAMwere conducted to understand the material behavior. Subsequently, various concepts were developed using a functional analysis conducted after creating a list of needs and requirements. Four concepts were developed, three of which were constructed and produced for further testing of radar properties in an NRL arch. The results of the work show that concept four, with a combination of PLA-M and PLA-E materials, proved to be the most promising for radar absorption. Unfortunately, I was not able to develop a mathematical model based on the test results. Despite this, the results provide valuable insights into how different parameters affect radar absorption in multilayer panels.

Additive Manufacturing (AM, also known as 3D printing) can produce novel three-dimensional structures using low-loss dielectric materials. This enables the construction of dielectrics with complex shapes that enable innovative microwave applications such as resonators, filters, and metamaterial lenses. This thesis addresses the production and characterization of cellular structures of various designed densities created with a low loss ceramic material, alumina (aluminum oxide), via vat photopolymerization. The permittivity of these printed structures is variable over roughly an octave, with a range of relative permittivites from 1.78 to 3.60, controlled via part geometry. Two additional materials, ferrite and nickel, have been explored for inclusion within these dielectric structures to enable the production of multi-material electromagnetic structures with conductive, magnetic, and dielectric elements. / Master of Science / Additive Manufacturing (AM, also known as 3D printing) has unique manufacturing capabilities. 3D printing can create structures that cannot be produced using traditional manufacturing methods. For example, sponge like structures, with internal voids inaccessible from the outside of the structure, can be created out of a variety of materials. Such structures, known as cellular structures, can be used to create new advanced materials. Ceramic cellular structures can be produced using 3D printing. Ceramics possess many advantages over other materials for use in high frequency radio systems, such as those used for radar and communications. Notably, ceramics are known as low-loss materials, meaning that when electromagnetic waves travel through them they lose less energy than other materials. Cellular structures can be used to vary a material property known as the dielectric constant. Creating cellular structures with designed dielectric constants will enable the creation of new and useful electromagnetic structures. Measuring how this material property changes with the geometry of the cellular structures is important to enable their use. These measurements are described in this work. Additionally, other materials are printed into the ceramic structures. Ferrite, a magnetic material, is extruded as a paste from a nozzle into the ceramic structures. This material is also important for radio systems. Nickel, a good conductor, has also been embedded into the ceramic to provide the ability to create electrically conductive paths inside the part.

Die vorliegende Arbeit befasst sich mit verschiedenen Textildruckverfahren und der terminologischen Untersuchung dieses Fachbereichs im Bereich Print-on-Demand. Die Untersuchung wurde am Beispiel der bei der sprd.net AG angewendeten Verfahren für die Sprachen Deutsch und Französisch angewendet.

Approved for public release, distribution is unlimited / Display technologies in the current market range from the simple and cheap incandescent bulb behind a graphic overlay to the upwardly expensive flat panel high definition plasma display. To provide a foundation of understanding for Light Emitting Polymers (LEP), samples were imaged in a scanning electron microscope. This was preformed to identify a potential method for answering questions on polymer charge mobility and diffusion mechanisms, which are currently unknown. Light Emitting Polymer (LEP) displays offer a viable alternative to the active matrix style, when an application calls for information to be sent in a simple visible format. By using the flexibility of the fabrication process, LEP displays can be applied to offer a low cost, lightweight, and durable means of communicating information during shipboard damage control and firefighting. A unique screen printing method was used in collaboration with Add-Vision, to produce a prototype that was designed, fabricated and tested for use in Naval shipboard firefighting evolutions. The application of the LEP technology to shipboard damage control was motivated by the experience gained from being both the Officer in Charge of a Naval Firefighting School and from time in the Fleet as a Damage Control Officer. / Lieutenant, United States Naval Reserve

Master thesis "Letterpress - Origin of Manual Typesetting" consists of the theoretical and the practical part. Theoretical part describes the origin and development of book printing and printed Latin script - proces of type casting and typesetting. Then, the life Johannes Gutenberg is briefly described. The information was partially ontains printed graphical compositions created using wooden letters for script printing in combination with two other graphical techniques of printing from height - monotype and linocut. The part of this work became the experimenting with graphical creative means.