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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2019

Optimization of Aluminum-Tin Ink Composition and Sintering in Atmospheric Conditions

This study will focus on the basics of generating an aluminum-tin ink that can sinter in air and exhibits properties near that of a solid aluminum-tin alloy. Sintering temperatures will also be assessed in this study. Once the optimal aluminum ink composition is determined, the optimal ink thickness for homogeneous sintering must be determined by additional experimentation. Additive manufacturing is a rapidly developing and growing manufacturing process and has proven successful in many different ways. Processes, such as extrusion three-dimensional (3D) printing and selective laser melting (SLM), have proven to work but have limitations, such as material capabilities or density issues. SLM is a revolutionary process for additive manufacturing of metals but cannot be used in outer space due to the need for metallic powder which would diffuse into the atmosphere in a zero-gravity environment. For this reason, metallic ink additive manufacturing is a potential solution. Work is being done on metallic ink additive manufacturing in a vacuum for electrical applications. This project has focused on developing an aluminum-tin metallic ink that can sinter without the need of a vacuum or inert gas-purged atmosphere in order to prevent oxidation of the aluminum by adding flux. Once a potential ink composition has been determined through sintering of small disks and thin layers of ink, the ink may be studied with a multimaterial 3D printer at NASA Marshall Space Flight Center (MSFC) in future experiments. If successful, this aluminum-tin ink will be capable for use on the International Space Station to make replacement parts quickly. Along with its zero-gravity advantages, this ink may also have applications on Earth because it may be extruded on a substrate with precise ceramic tips in a 3D printing process. This would allow the fabrication of precise, complex shapes and may generate a much faster and more efficient printing process as compared with traditional powder bed additive manufacturing processes. The process would not be limited by a small building volume because the system would not require an enclosed chamber.

Courtright, Z. S.↗
NASA NTRS1986

Ink-jet printing of silver metallization for photovoltaics

The status of the ink-jet printing program at Purdue University is described. The drop-on-demand printing system was modified to use metallo-organic decomposition (MOD) inks. Also, an IBM AT computer was integrated into the ink-jet printer system to provide operational functions and contact pattern configuration. The integration of the ink-jet printing system, problems encountered, and solutions derived were described in detail. The status of ink-jet printing using a MOD ink was discussed. The ink contained silver neodecanate and bismuth 2-ethylhexanoate dissolved in toluene; the MOD ink decomposition products being 99 wt% AG, and 1 wt% Bi.

Vest, R. W.↗
NASA NTRS2017

High Performance Composite Dielectric Ink for Ultracapacitors

The present invention is a dielectric ink and means for printing using said ink. Approximately 10-20% of the ink is a custom organic vehicle made of a polar solvent and a binder. Approximately 30-70% of the ink is a dielectric powder having an average particle diameter of approximately 10-750 nm. Approximately 5-15% of the ink is a dielectric constant glass. Approximately 10-35% of the ink is an additional amount of solvent. The ink is deposited on a printing substrate to form at least one printed product, which is then dried and cured to remove the solvent and binder, respectively. The printed product then undergoes sintering in an inert gas atmosphere.

Rolin, Terry D.↗
NASA NTRS1972

Properties of conductive thick-film inks

Ten different conductive inks used in the fabrication of thick-film circuits were evaluated for their physical and handling properties. Viscosity, solid contents, and spectrographic analysis of the unfired inks were determined. Inks were screened on ceramic substrates and fired for varying times at specified temperatures. Selected substrates were given additional firings to simulate the heat exposure received if thick-film resistors were to be added to the same substrate. Data are presented covering the (1) printing characteristics, (2) solderability using Sn-63 and also a 4 percent silver solder, (3) leach resistance, (4) solder adhesion, and (5) wire bonding properties. Results obtained using different firing schedules were compared. A comparison was made between the various inks showing general results obtained for each ink. The changes in firing time or the application of a simulated resistor firing had little effect on the properties of most inks.

Holtze, R. F.↗
NASA NTRS1983

Development of aircraft lavatory compartments with improved fire resistance characteristics. Phase 4: Sandwich panel decorative ink development

Five chemically different resin systems with improved fire resistance properties were studied for a possible screenprinting ink application. Fire resistance is hereby defined as the cured ink possessing improvements in flammability, smoke emission, and thermal stability. The developed ink is for application to polyvinyl fluoride film. Only clear inks without pigments were considered. Five formulations were evaluated compared with KC4900 clear acrylic ink, which was used as a baseline. The tests used in the screening evaluation included viscosity, smoke and toxic gas emission, limiting oxygen index (LOI), and polyvinyl fluoride film (PVF) printability. A chlorofluorocarbon resin (FPC461) was selected for optimization studies. The parameters for optimization included screenprinting process performance, quality of coating, and flammability of screenprinted 0.051-mm (0.002-in.) white Tedlar. The quality of the screenprinted coating on Tedlar is dependent on viscosity, curing time, adhesion to polyvinyl fluoride film, drying time (both inscreen and as an applied film), and silk screen mesh material and porosity.

Jayarajan, A.↗
NASA NTRS2013

Conductive Carbon Nanotube Inks for Use with Desktop Inkjet Printing Technology

Inkjet printing is a common commercial process. In addition to the familiar use in printing documents from computers, it is also used in some industrial applications. For example, wire manufacturers are required by law to print the wire type, gauge, and safety information on the exterior of each foot of manufactured wire, and this is typically done with inkjet or laser printers. The goal of this work was the creation of conductive inks that can be applied to a wire or flexible substrates via inkjet printing methods. The use of inkjet printing technology to print conductive inks has been in testing for several years. While researchers have been able to get the printing system to mechanically work, the application of conductive inks on substrates has not consistently produced adequate low resistances in the kilohm range. Conductive materials can be applied using a printer in single or multiple passes onto a substrate including textiles, polymer films, and paper. The conductive materials are composed of electrical conductors such as carbon nanotubes (including functionalized carbon nanotubes and metal-coated carbon nanotubes); graphene, a polycyclic aromatic hydrocarbon (e.g., pentacene and bisperipentacene); metal nanoparticles; inherently conductive polymers (ICP); and combinations thereof. Once the conductive materials are applied, the materials are dried and sintered to form adherent conductive materials on the substrate. For certain formulations, increased conductivity can be achieved by printing on substrates supported by low levels of magnetic field alignment. The adherent conductive materials can be used in applications such as damage detection, dust particle removal, smart coating systems, and flexible electronic circuitry. By applying alternating layers of different electrical conductors to form a layered composite material, a single homogeneous layer can be produced with improved electrical properties. It is believed that patterning alternate layers of different conductors may improve electrical pathways through alignment of the conductors and band gap optimization. One feature of this innovation is that flexible conductive traces could be accomplished with a conductive ink having a surface resistivity of less than 10 ohms/square. Another result was that a composite material comprising a mixture of carbon nanotubes and metallic nanoparticles could be applied by inkjet printing to flexible substrates, and the resulting applied material was one to two orders of magnitude more conductive than a material made by printing inks containing carbon nanotubes alone.

Roberson, Luke↗
NASA NTRS2019

Design of Experiment for the Measurement of Aerosol Droplet Size Distribution of Temperature-Controlled Thermally Atomized Printed Electronic Inks

In-Space Manufacturing (ISM) centers around NASA’s growing need and ability to produce space technologies on demand in space. As the future of long term presence in space and deep space exploration approach, fundamental questions of our dependence on earth resupply to Low Earth Orbit (LEO) remain unanswered. ISM is leading various effort to evaluate the feasibility of producing essential spares and redundant parts on demand to enable a sustainable space-based supply chain model for part resupply. Among the parts and systems being considered, Avionics form the neural network of modern day aircraft and space vehicles providing a wealth of information ranging from Guidance, Navigation, and Control (GN&C) systems to on board Environmental Control and Life Support (ECLS) systems. Recent advances in the use of Aerosol Jet Technology to print Avionics components ranging from electrical traces on a circuit board to complex transistors and sensors raise the possibility of using such technology to reproduce or recreate electronic parts on demand with the help of custom electronics 3D printers. The challenge herein lies within the ability of such printers to generate and deposit an aerosol of electronic material utilizing processes independent of or enhanced by gravity to ensure controllably identical or improved behavior of the aerosol in an International Space Station (ISS) laboratory and on the ground. The behavior as well as the hazards and properties associated with such aerosols in a microgravity environment must be understood well in order to merit a feasible approach to utilizing them for manufacturing in space. In this report, we outline the experimental setup of a modified conventional vaping device to be used as the ideal gravity independent thermal atomization mechanism to generate aerosol. Our objective is to identify the ideal mass, density, and volume of our aerosolized droplets of ink to conclude that there exist a threshold of aerosolized ink droplet sizes that are indeed independent of the effects of gravity and remain stable after atomization. We use a Malvern Spraytec® Spray Particle Size Analyzer to perform real-time laser diffraction measurement of our ink droplets during atomization. The droplet size between conductive ink, dielectric ink and vegetable glycerin have been measured and contrasted. Furthermore, the mechanism of thermal atomization versus traditional pneumatic and ultrasonic atomization for operation in microgravity have been explored.

Wu, Chih-Hao↗
NASA NTRSDate not supplied

Process Development for Printing Copper Conductible Ink on Flexible Substrates Using Aerosol Jet Technology

Rise in demand for wearable consumer electronics products has given an impetus to the development of flexible electronics technology encompassing flexible substrates and compatible circuitry. Also, additive manufacturing of flexible electronics is emerging rapidly via several techniques such as Inkjet and Aerosol Jet Printing (AJP). The basic component of all flexible circuits to be printed by these technologies is conductible ink, which is generally silver ink. Few studies exist on the printing of copper conductible ink and not many copper ink formulations are available in the market as that of silver inks. This study aims to develop a process development study for deposition of copper conductible lines on flexible substrates using the aerosol jet printing technology. The process development study includes investigation of photosintering parameters for obtaining desirable electrical resistance and shear load to failure values for the printed line. Different pre-drying techniques such as oven pre-drying and platen pre-drying have been used for improving the electrical and mechanical properties of the conductive traces. Techniques such as optical microscopy and white light interferometry have been used for the characterization of print quality of the conductible lines.

printed electronics↗
NASA NTRS1985

Fire-retardant decorative inks for aircraft interiors

Commercial and experimental fire retardants were screened as potential fire retardants for acrylic printing inks used on aircraft interior sandwich panels. The fire retardants are selected according to their physical properties and their thermostabilities. A criterion for selecting a more stable fire retardant is established. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are used to determine thermostabilities. Results show that the fire retardant formulations are more thermally stable than the acrylic ink control. It is determined that an ink formulation containing a brominated phenol and carboxy-terminated butadiene acrylonitrile which has been modified with a brominated polymeric additive (BPA), yields the highest limiting oxygen index (LOI) of all the compounds tested. All of the fire-retardant formulations have a higher oxygen index than the baseline acrylic ink.

Kourtides, D. A.↗
NASA NTRS1987

Ink jet assisted metallization for low cost flat plate solar cells

Computer-controlled ink-jet-assisted metallization of the front surface of solar cells with metalorganic silver inks offers a maskless alternative method to conventional photolithography and screen printing. This method can provide low cost, fine resolution, reduced process complexity, avoidance of degradation of the p-n junction by firing at lower temperature, and uniform line film on rough surface of solar cells. The metallization process involves belt furnace firing and thermal spiking. With multilayer ink jet printing and firing, solar cells of about 5-6 percent efficiency without antireflection (AR) coating can be produced. With a titanium thin-film underlayer as an adhesion promoter, solar cells of average efficiency 8.08 percent without AR coating can be obtained. This efficiency value is approximately equal to that of thin-film solar cells of the same lot. Problems with regard to lower inorganic content of the inks and contact resistance are noted.

Teng, K. F.↗
NASA NTRS1998

The Effect of Jetting Parameters on the Performance of Droplet Formation for Ink-Jet Rapid Prototyping

Heinzl et al. (1985) reports that experiments in ink-jets to produce drawings or signals occurred as early as 1930. Various companies such as IBM and Pitney-Bowes have conducted extensive studies on these devices for many years. Many such reports are available in such journals as the IBM Journal of Research and Development. While numerous articles have been published on the jetting characteristics of ink and water, the literature is rather limited on fluids such as waxes (Gao & Sonin 1994) or non-water based fluids (Passow, et al. 1993). This present study extends the knowledge base to determine the performance of molten waxes in "ink-jet" type printers for rapid prototyping. The purpose of this research was to qualitatively and quantitatively study the droplet formation of a drop-on-demand ink-jet type nozzle system for rapid prototyping.

Helmer, Wayne↗
NASA NTRS1985

Ink jet printing of silver metallization for photovoltaics

Progress was made in the continuing development of the ink jet printing system for thick film circuits. The unit being used is a prototype ink jet printer. One of the first tasks completed was the complete documentation of this ink jet printing system as it existed. It was determined that this was an essential step in deciding what modifications were needed to the system and how these modifications would be implemented. Design modification studies were started for electronic, mechanical, and programming aspects of the ystem. The areas needeing improvement were discussed and applicable changes decided upon. Some improvments were completed. Although the general areas needing improving were identified and some changes decided upon, the exact details of how other changes can be implemented are yet been decided.

Vest, R. W.↗
NASA NTRS1988

Fire-Retardant Decorative Inks For Aircraft Interiors

Report describes testing of commercial and experimental fire retardants for incorporation into acrylic printing inks used on aircraft-interior sandwich panels. Films of acrylic ink containing fire-retardant additives prepared by casting on glass plates. Solvent evaporated in vacuum, cast films cured at 80 to 100 degree C for 30 minutes in air-circulating oven. Thermochemical properties of films examined by thermogravimetric analysis and differential scanning calorimetry (DSC). Samples of inks cast on sheets of polyvinylfloride (PVF), and their limiting oxygen indices and smoke evolution measured.

Kourtides, D. A.↗
NASA NTRS1989

Silver Ink For Jet Printing

Metallo-organic ink containing silver (with some bismuth as adhesion agent) applied to printed-circuit boards and pyrolized in air to form electrically conductive patterns. Ink contains no particles of silver, does not have to be mixed during use to maintain homogeneity, and applied to boards by ink-jet printing heads. Consists of silver neodecanoate and bismuth 2-ethylhexanoate dissolved in xylene and/or toluene.

Vest, R. W.↗
NASA NTRSDate not supplied

Process Recipes for Additively Printed Copper Ink Flexible Circuits using Direct Write Methods

In this paper, the process-recipes and process-performance relationships for additive-printing of copper circuits using direct-write methods have been studied. The process has been implemented on the direct write platform. Interest in the use of additive printing methods for the manufacture of micro-circuits has grown immensely in recent times. Direct write methods have been shown to have the ability to create circuits in a limited manner. However, the process recipes and the effect of process parameters on the manufactured properties are not well understood. Copper ink is a good and cost-effective alternative to silver ink but its use has lagged owing to an increased propensity for oxidation. In this paper, photonic curing has been used to sinter copper ink to make the traces conductive. The method flashes high energy light that sinter metal particles instantaneously and the temperature of the substrate remains low. The effect of the different photonic sintering profiles on the mechanical and electrical properties of the printed traces has been studied in this paper.The print process parameters also play an important role in the line width and height that has been studied to print with the desired line profile for the end application. An LC filter circuit is been printed with SMD components been attached using an electrically conductive adhesive (ECA). The manufactured flexible LC filter is been tested for its frequency sweep to compare with the commercially available LC filer with the help of the Bode plot.

Process control↗
NASA NTRS1984

Fire-retardant decorative inks for aircraft interiors

Commercial and experimental fire retardants were screened for possible use wiith acrylic printing inks on aircraft interior sandwich panels. The fire retardants were selected according to their physical properties and thermostabilities. Thermostabilities were determined by thermogravimetric analysis and differential scanning calorimetry. A criterion was then established for selecting the more stable agent. Results show that some of the bromine-containing fire retardants are more thermostable than the acrylic ink, alone, used as a control. Also, the bromine-containing fire retardants yield even better limiting oxygen index values when tested after adding carboxy-terminated butadiene acrylonitrile (CTBN) rubber.

Nir, Z.↗
NASA NTRS1988

Ink-Jet Printer Forms Solar-Cell Contacts

Contacts formed in controllable patterns with metal-based inks. System forms upper metal contact patterns on silicon photovoltaic cells. Uses metallo-organic ink, decomposes when heated, leaving behind metallic, electrically conductive residue in printed area.

Alexander, Paul, Jr.↗
NASA NTRS2024

Direct Ink Write 3D Printing of Fully Dense and Functionally Graded Liquid Metal Elastomer Foams

Liquid metal (LM) elastomer composites offer promising potential in soft robotics, wearable electronics, and human-machine interfaces. Direct ink write (DIW) 3D printing offers a versatile manufacturing technique capable of precise control over LM microstructures, yet challenges such as interfilament void formation in multilayer structures impact material performance. Here, a DIW strategy is introduced to control both LM microstructure and material architecture. Investigating three key process parameters–nozzle height, extrusion rate, and nondimensionalized nozzle velocity–it is found that nozzle height and velocity predominantly influence filament geometry. The nozzle height primarily dictates the aspect ratio of the filament and the formation of voids. A threshold print height based on filament geometry is identified; below the height, significant surface roughness occurs, and above the ink fractures, which facilitates the creation of porous structures with tunable stiffness and programmable LM microstructure. These porous architectures exhibit reduced density and enhanced thermal conductivity compared to cast samples. When used as a dielectric in a soft capacitive sensor, they display high sensitivity (gauge factor = 9.0), as permittivity increases with compressive strain. These results demonstrate the capability to simultaneously manipulate LM microstructure and geometric architecture in LM elastomer composites through precise control of print parameters, while maintaining geometric fidelity in the printed design.

Spencer Pak↗