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Modification of Ammonium Perchlorate Composite Propellant to Tailor Pressure Output Through Additively Manufactured Grain GeometriesJulie Suzanne Bach (11560309) 22 November 2021 (has links)
<div>The new technique of Vibration-Assisted 3D Printing (VAP) offers significant potential for leveraging the geometric flexibility of additive manufacturing (AM) into the realm of solid energetics. The first part of this work compares the print capabilities of a custom-made VAP printer to those of an established commercial direct-write printer using a polymer clay. Characterization tests were conducted and a variety of other shapes were printed comparing the two methods in their turning quality, feature resolution, unsupported overhang angle, negative space feature construction, and less-than-fully-dense self-supported 3D lattices. The porosity and regularity of the printed lattices were characterized using X-ray microtomography (MicroCT) scans. The quality of the shapes was compared using statistical methods and a MATLAB edge-finding code. The results show that the VAP printer can manufacture parts of superior resolution than the commercial printer, due to its ability to extrude highly viscous material through a smaller nozzle diameter. The VAP print speeds were also found to be as high as twenty times higher than those of the direct write printer.</div><div>Following up on this work, a second study explored the possibility of modifying grain geometry through variation of printed infill design using an ammonium perchlorate composite propellant (APCP). In the propellant formulation, a polymer that cures under ultra-violet (UV) light was used instead of the more common hydroxyl-terminated polybutadiene (HTPB). Although this formulation is a less-effective fuel than HTPB, its use enables layer-by-layer curing for improved structural strength during printing. Using VAP, cylindrical propellant charges were prepared using a gyroidal infill design with a range of internal porosities (infill amounts). Some additional propellant grains were prepared with both vertical and concentric layering of different infill amounts. These grains were then burned beginning at atmospheric pressure in a constant-volume Parr cell to measure the resulting pressure output. Analysis of the pressure trace data shows that a less-dense infill increases the maximum pressurization rate, due to the presence of small voids spaced roughly uniformly throughout the grain that increase the burning surface area. We show that additive manufacturing-based propellant grain modification can be used to tailor the pressure-time trace through adjustment of the number and size of small voids. Specifically, this study shows that, using a graded functional geometry, the duration of gas generation can be controlled. This work represents a preliminary effort to explore the possibilities to propellant</div><div>12</div><div>manufacture offered by additive manufacturing and to begin to address the challenges inherent in making it practical.</div>
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ANALYSIS OF FRICTION STIR ADDITIVE MANUFACTURING AND FRICTION STIR WELDING OF AL6061-T6 VIA NUMERICAL MODELING AND EXPERIMENTSNitin Rohatgi (9757331) 14 December 2020
<div>Aluminum 6061 is extensively used in industry and welding and additive manufacturing (AM) of Al6061 offer flexibility in manufacturing. Solid-state welding and AM processes can overcome the shortcomings of fusion-based processes, such as porosity and hot cracking. In this thesis, friction stir welding and friction stir additive manufacturing, which are both based on the concepts of friction stir processing (solid-state), were studied. The welding parameters for a sound weld during friction stir welding of Al6061-T6 alloy were determined based on the experimental and numerical analysis. Formation of tunnel defects and cavity defects was also studied. A Coupled Eulerian-Lagrangian (CEL) finite element model was established to analyze the process, where the workpiece was modeled as an Eulerian body, and the tool as Lagrangian. The model was validated by conducting experiments and correlating the force measured by a three-axis dynamometer. The experimentally validated simulation model was used to find an optimum parameter set for the sound weld case.</div><div>To demonstrate the friction stir additive manufacturing process, a 40 mm × 8 mm × 8 mm (L×B×H) material was fabricated by adding five 1.6 mm thick plates. A similar coupled Eulerian-Lagrangian based finite element model was used to predict the effects of sound process parameters, such as the tool’s rotational speed and the translational speed. The temperature predicted by the model was used to predict the microhardness distribution in the sample and to further elucidate the hardness change in the weld zone, which showed a good agreement with the experimental results. The microstructure of the samples was analyzed, and the mechanical properties of the additive manufactured samples were characterized and compared with those of other AM techniques via tensile tests and tensile shear tests.</div>
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Enhancing Solid Propellants with Additively Manufactured Reactive Components and Modified Aluminum ParticlesDiane Collard (11189886) 27 July 2021 (has links)
<p>A variety of methods have been
developed to enhance solid propellant burning rates, including adjusting
oxidizer particle size, modifying metal additives, tailoring the propellant
core geometry, and adding catalysts or wires. Fully consumable reactive wires
embedded in propellant have been used to increase the burning rate by
increasing the surface area; however, the manufacture of propellant grains and
the observation of geometric effects with reactive components has been
restricted by traditional manufacturing and viewing methods. In this work, a
printable reactive filament was developed that is tailorable to a number of use
cases spanning reactive fibers to photosensitive igniters. The filament employs
aluminum fuel within a printable polyvinylidene fluoride matrix that can be
tailored to a desired burning rate through stoichiometry or aluminum fuel configuration
such as particle size and modified aluminum composites. The material is
printable with fused filament fabrication, enabling access to more complex
geometries such as spirals and branches that are inaccessible to traditionally
cast reactive materials. However, additively manufacturing the reactive
fluoropolymer and propellant together comes attendant with many challenges
given the significantly different physical properties, particularly regarding adhesion.
To circumvent the challenges posed by multiple printing techniques required for
such dissimilar materials, the reactive fluoropolymer was included within a solid
propellant carrier matrix as small fibers. The fibers were varied in aspect
ratio (AR) and orientation, with aspect ratios greater than one exhibiting a
self-alignment behavior in concordance with the prescribed extrusion direction.
The effective burning rate of the propellant was improved nearly twofold with
10 wt.% reactive fibers with an AR of 7 and vertical orientation. </p>
<p>The reactive wires and fibers in
propellant proved difficult to image in realistic sample designs, given that
traditional visible imaging techniques restrict the location and dimensions of the
reactive wire due to the necessity of an intrusive window next to the wire, a
single-view dynamic X-ray imaging technique was employed to analyze the
evolution of the internal burning profile of propellant cast with embedded
additively manufacture reactive components. To image complex branching
geometries and propellant with multiple reactive components stacked within the
same line of sight, the dynamic X-ray imaging technique was expanded to two
views. Topographic reconstructions of propellants with multiple reactive fibers
showed the evolution of the burning surface enhanced by the geometric effects
caused by the faster burning fibers. These dual-view reconstructions provide a
method for accurate quantitative analysis of volumetric burning rates that can
improve the accessibility and viability of novel propellant grain designs.</p>
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Additive Manufacturing solving Spare Parts Challenges within Heavy Equipment IndustryNamik, Ayad January 2022 (has links)
Background Companies which operate within heavy equipment are highly dependent on a continuous spare part stream to minimise their production downtime. The disruption of the pandemic known as Covid19 has brought the global supply chain to its knee, and countless companies have been affected by the global supply shortage. One of such industries is heavy equipment which comprises heavy-duty vehicles, large equipment, large-scale infrastructure, intricate or numerous processes with high operation cost and a unique set of challenges. Consequently, the demand for spare parts within heavy equipment can be extremely unpredictable and erratic, since the life cycle of machinery is connected to systems owned by the customers and its applications. Therefore, understanding the heavy equipment industry could allow for new innovative ways for managing spare part challenges. One of the methods for solving spare part challenges in other industries according to previous research has been the utilisation of additive manufacturing (AM).The AM technology is based on incremental layer-by-layer manufacturing compared to conventional manufacturing (CM) which mostly depend on subtractive manufacturing processes. Research questions RQ1: What are the challenges within the heavy equipment industry regarding spare part management? RQ2: How can the heavy equipment industry utilise additive manufacturing to overcome challenges surrounding spare parts management? Method The literature review comprised of the identification of spare part management challenges surrounding heavy equipment, the capabilities of AM surrounding spare parts as well as optimisation methods for existing parts with AM. Whereas the interviews consisted of two sets of interview groups (i.e., heavy equipment and AM based companies). Lastly, the experiment consisted of validating gathered data as well as identifying AMs capabilities based on a physical object (i.e., lifting bracket). Findings The findings show the existing spare part management challenges within heavy equipment are related to four dimensions namely: warehousing, cost, lead times and the environment.Whereas the findings surrounding AMs capabilities for mitigating spare part management challenges showed that, AM enable the production of low volume parts with low lead time replenishment. This could minimise overall waste within the heavy equipment industry, where central warehousing could be reduced as well as the total lead time for customers.
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Robotic P-GMA DED AM of Aluminum for Large StructuresCanaday, Jack H. January 2021 (has links)
No description available.
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Microstructural Characterization of LENS<sup>TM</sup> Ti-6Al-4V: Investigating the Effects of Process Variables Across Multiple Deposit GeometriesDavidson, Laura Christine January 2018 (has links)
No description available.
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A Study of Additive manufacturing Consumption, Emission, and Overall Impact With a Focus on Fused Deposition ModelingTimothy Simon (9746375) 28 July 2021 (has links)
<p>Additive manufacturing (AM) can
be an advantageous substitute to various traditional manufacturing
techniques. Due to the ability to
rapidly create products, AM has been traditionally used to prototype more
efficiently. As the industry has progressed, however, use cases have gone
beyond prototyping into production of complex parts with unique
geometries. Amongst the most popular of
AM processes is fused deposition modeling (FDM). FDM fabricates products through an extrusion
technique where plastic filament is heated to the glass transition temperature
and extruded layer by layer onto a build platform to construct the desired
part. The purpose of this research is to
elaborate on the potential of this technology, while considering environmental
impact as it becomes more widespread throughout industry, research, and
academia.</p>
<p>Although AM consumes resources
more conservatively than traditional methodologies, it is not free from having
environmental impacts. Several studies have shown that additive manufacturing
can affect human and environmental health by emitting particles of a dynamic
size range into the surrounding environment during a print. To begin this
study, chapters investigate emission profiles and characterization of emissions
from FDM 3D printers with the intention of developing a better understanding of
the impact from such devices. Background work is done to confirm the occurrence
of particle emission from FDM using acrylonitrile butadiene styrene (ABS)
plastic filament. An aluminum bodied 3D printer is enclosed in a chamber and
placed in a Class 1 cleanroom where measurements are conducted using high
temporal resolution electrical low-pressure impactor (ELPI), scanning mobility
particle sizer (SMPS), and optical particle sizer (OPS), which combined measure
particles of a size range 6-500nm. Tests
were done using the NIST standard test part and a honeycomb infill cube. Results from this study show that particle
emissions are closely related to filament residence time in the extruder while
less related to extruding speed. An
initial spike of particle concentration is observed immediately after printing,
which is likely a result of the long time required to heat the extruder and bed
to the desired temperature. Upon conclusion of this study, it is theorized that
particles may be formed through vapor condensation and coagulation after being
released into the surrounding environment.</p>
<p>With confirmation of FDM
ultrafine particle emission at notable concentrations, an effort was
consequently placed on diagnosing the primary cause of emission and energy
consumption based on developed hypotheses. Experimental data suggests that
particle emission is mainly the result of condensing and agglomerating
semi-volatile organic compounds. The
initial emission spike occurs when there is dripping of semi-liquid filament
from the heated nozzle and/or residue left in the nozzle between prints; this
supports the previously stated hypothesis regarding residence time. However,
the study shows that while printing speed and material flow influence particle
emission rate, the effects from these factors are relatively insignificant.
Power profile analysis indicates that print bed heating and component
temperature maintaining are the leading contributors to energy consumption for FDM
printers, making time the primary variable driving energy input.</p>
<p>To better understand the severity
of FDM emissions, further investigation is necessary to diligence the makeup of
the process output flows. By collecting exhaust discharge from a Makerbot
Replicator 2x printing ABS filament and diffusing it through a type 1 water
solution, we are able to investigate the chemical makeup of these compounds.
Additional exploration is done by performing a filament wash to investigate
emissions that may already be present before extrusion. Using solid phase
micro-extraction, contaminants are studied using gas chromatography mass
spectrometry (GCMS) thermal desorption. Characterization of the collected
emission offers more comprehensive knowledge of the environmental and human
health impacts of this AM process.</p>
<p>Classification of the
environmental performance of various manufacturing technologies can be achieved
by analyzing their input and output material, as well as energy flows. The unit
process life cycle inventory (UPLCI) is a proficient approach to developing
reusable models capable of calculating these flows. The UPLCI models can be connected to estimate
the total material and energy consumption of, and emissions from, product
manufacturing based on a process plan. The final chapter focuses on using the
knowledge gained from this work in developing UPLCI model methodology for FDM,
and applying it further to the second most widely used AM process:
stereolithography (SLA). The model created for the FDM study considers material
input/output flows from ABS plastic filament.
Energy input/output flows come from the running printer, step motors,
heated build plate, and heated extruder. SLA also fabricates parts layer by
layer, but by the use of a photosensitive liquid resin which solidifies when
cured under the exposure of ultraviolet light. Model material input/output
flows are sourced from the photosensitive liquid resin, while energy
input/output flows are generated from (i) the projector used as the ultraviolet
light source and (ii) the step motors. As shown in this work, energy flow is
mostly time dependent; material flows, on the other hand, rely more on the
nature of the fabrication process. While a focus on FDM is asserted throughout
this study, the developed UPLCI models show how conclusions drawn from this
work can be applied to different forms of AM processes in future work.</p>
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Thermal-Stress Characteristics of Large Area Additive ManufacturingFriedrich, Brian K., II 09 May 2022 (has links)
No description available.
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Microstructure Evolution and Strengthening Effects of Carbide Phases in Mar-M 509 Cobalt Alloy Fabricated by Laser Powder Bed FusionJack Michael Lopez (15324055) 21 April 2023 (has links)
<p> Laser powder bed fusion (LPBF) is a rapidly emerging manufacturing technology capable of producing complex part geometries through the repeated, precise laser melting of metallic powder layers. At present, the process is primarily employed in high-value-added applications which exist in the aerospace, biomedical, and dental industries. As industrial implementation of LPBF has matured, research has focused on established materials for which there are already large bodies of literature and regulatory approval, such as Inconel 718, Inconel 625, Ti-6Al-4V, and 316 stainless steel. However, the rapid solidification process inherent to LPBF leads to vastly different microstructures with improved strength compared to these traditional materials in cast or wrought forms. In general, the high solidification velocity and thermal gradients result in cellular and dendritic solidification structures with finer grain and precipitate sizes than conventionally processed alloys. These microstructure changes warrant the exploration of new alloy systems and reevaluation of historically cast compositions with optimized microstructures, especially considering the tunability of a digitally controlled fabrication process. This work examines laser powder bed fusion of Mar-M 509, a carbide-strengthened cobalt alloy that is typically investment cast directly into complex-shaped components such as nozzle guide vanes (NGVs). NGVs are stationary components in gas turbine engines for propulsion and energy production which require strength under moderate mechanical loading at high temperatures. Investment cast microstructures have porosity defects in slower-cooled regions due to lack of liquid feed to interdendritic regions. As-printed, the cellular and dendritic Mar-M 509 LPBF microstructures lead to the formation of continuous, fiber-like, eutectic carbide structures in the intercellular and interdendritic regions, which limit macroscopic ductility. Thermo-Calc is used for calculation of phase diagrams (CALPHAD) to estimate the equilibrium transformation temperatures of MC, M23C6, and M7C3-type carbides, which informs design of isothermal heat treatments to engineer microstructures with enhanced ductility over the as-printed or cast versions of Mar-M 509 while maintaining tensile strength. Scanning and transmission electron microscopy reveals the composition and distribution of carbide phases as a function of heat treatment temperature. Lastly, heat treatment recommendations for nozzle guide vanes are made. </p>
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Adoption of Additive Manufacturing in the Food Industry : Exploring marketing, sales, and after-sales strategies for the adoption of Additive Manufacturing in the food industry.Erol, Burak, Datar, Maitreya Chandrashekhar January 2022 (has links)
Additive Manufacturing (AM) is a technology that enables to print three dimensional solid objects which can be metal, plastic, and similar. AM has a lot of advantages such as lead time reduction and reduction in the number of steps required for manufacturing compared to the traditional manufacturing (TM) method. This research is focused on adoption of AM in the food manufacturing industry. The use of AM in the food industry currently seems to be low. Therefore, the main aim of the research is to understand adoption of AM through marketing, sales, and after-sales strategies, which can be best suited for introduction and saturation of AM products and applications in the food industry. The primary data is gathered from the potential customers (experts from the food industry), sales personnel who sell products and machinery in the food industry and the employees of the sponsor company, and it consists of thirteen different interviews. Qualitative interviews were conducted to obtain an in-depth knowledge about the perceptions and perspectives of AM in the food industry. AM has the potential to be adopted as the main manufacturing method for spare parts in the food industry. But, considering the market today, the potential of adoption seems to be wasted. Three different analyses help in determining the current situation of the AM industry and help to understand the potential that AM brings to the food industry. Outcomes of the qualitative interviews present the researchers with in-depth knowledge of facilitators and barriers that AM companies may face when approaching customers from the food industry. Outcomes of the qualitative interviews also suggest that there is limited knowledge about AM in the food industry. There is also a knowledge gap about the regulations and possibilities to use AM in the food industry based on these regulations. Indeed, food manufacturers are interested in the adoption of newer technologies and present the researchers with the formation of various themes to develop strategies for adoption of AM, through a recommendable marketing, sales and aftersales strategy that can be employed by AM companies.
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