Baigiamajame magistro darbe atliktas įprastų ir UV dažų palyginamasis kokybės tyrimas. Atliktas įprastų ir UV dažų atspaudų spalvinių charakterisikų palyginimas esant D50 ir D65 šviesos šaltiniams, ištirtas spalvų spausdinimo stabilumas. Nustatyta, kad įprastųjų ir UV dažų galimų spalvų diapazonas yra artimas esant D50 šviesos šaltiniui ir akivaizdžiai skiriasi esant D65 šviesos šaltiniui, kas rodo skirtingą fluorescencinio komponento indėlį. Eksperimentiškai ištirtos popieriaus ofsetinių atspaudų trinties savybės ir nustatyti statinis ir kinetinis trinties koeficientai. Nustatyta, kad įprastiniai ir UV dažai didina atspaudo į popierių statitinio trinties koeficiento dydį ir mažina kinetinio koeficiento dydį. Atliktas dviejų rūšių popieriaus su įprastais ir UV dažais šiurkštumo palyginamasis tyrimas ir nustatyta, kad įprasti dažai atspaudų paviršiaus šiukštumą stipriai didina, o UV dažų poveikis priklauso nuo popieriaus rūšies. Išnagrinėjus teorinius ir praktinius įprastų ir UV dažų skirtumus, pateikiamos baigiamojo darbo išvados ir siūlymai. Darbą sudaro 6 dalys: įvadas, apžvalga, eksperimentinė dalis, rezultatai ir jų aptarimas, išvados ir siūlymai, literatūros sąrašas. Darbo apimtis – 67 p. teksto be priedų, 59 iliustr., 1 lent., 15 bibliografinių šaltinių. Atskirai pridedami darbo priedai. / In master of science thesis is investigated the quality of conventional and UV curable prints. Performed comparison between two types of inks color characteristics at illuminants D50 and D65 and examined colors printing stability. It was fund, that diapason of conventional and UV inks are more similar at illuminant D50 and it is significantly different at illuminant D65. Results mean, that fluorescence’s component is different in different type of inks. Experimentally investigated offset print’s friction properties and determined the static and kinetic coefficients of friction. Determined, that conventional and UV inks increase static friction coefficient and reduce kinetic friction coefficient between paper and print. Also, investigated two different types of paper and prints made with conventional and UV inks roughness properties comparison and determined, that conventional inks strongly increase roughness of prints surface and influence of UV inks depend on paper’s type. Structure: introduction, review, experiment, conclusions and suggestions, references. Thesis consists of: 67 p. text without appendixes, 59 pictures, 1 table, 15 bibliographical entries. Appendixes included.

Microsieves are permeable membranes with excellent properties for filtration applications. In this thesis the inkjet-technology is applied (1) to manufacture micro-porous microsieves, and (2) to reinforce the mechanical stability of float-cast, nano-porous microsieves: (1) The current process for inkjet-printed microsieves includes a manual step which is substituted by inkjet printing in order to increase the level of automation. The obtained microsieves are characterized regarding the pore size distribution. Effects which occur during the manufacture and broaden the pore size distribution are identified. Based on the results, the process is improved to obtain fully inkjet-printed microsieves with a narrowed pore size distribution. (2) The mechanical stability of fragile, float-cast microsieves is improved by the application of inkjet-printed reinforcement patterns on top of the microsieves. A machine is built to combine both technologies of float-casting and inkjet printing. The printing process is improved to manufacture reinforcement patterns of well-defined geometry. / Mikrosiebe sind permeable Membranen mit herausragenden Eigenschaften für die Anwendung in der Filtration. In der vorliegenden Dissertation wird die Inkjet-Drucktechnologie angewandt, um (1) mikroporöse Mikrosiebe herzustellen und (2) nanoporöse Mikrosiebe mechanisch zu stabilisieren: (1) Die Herstellung von Mikrosieben mittels Inkjet-Druck beinhaltet momentan einen manuellen Schritt, der durch einen Inkjet-Druckschritt ersetzt wird, um den Automatisierungsgrad des Verfahrens zu erhöhen. Die Mikrosiebe werden bezüglich der Porengrößenverteilung untersucht. Auftretende Effekte, die die Porengrößenverteilung verbreitern, werden identifiziert. Aus den Resultaten dieser Analyse wird der Prozess optimiert, um Mikrosiebe mit einer engen Porengrößenverteilung herzustellen. (2) Die mechanische Stabilität von fragilen Mikrosieben, die mittels Float-Casting hergestellt werden, wird durch das Aufbringen einer Stützstruktur mittels Inkjet-Druck verstärkt. Ein Maschinensetup wird aufgebaut um beide Technologien des Float-Castings und des Inkjet-Drucks zu kombinieren. Weiterhin wird der Prozess dahingehend optimiert, Stützstrukturen mit wohl-definierten Parametern zu erzielen.

<p>The performance of solid rocket motors (SRMs) is extremely dependent on propellant formulation, operating pressure, and initial grain geometry. Traditionally, propellant grains are cast into molds, but it is difficult to remove the grains without damage if the geometry is too complex. Cracks or voids in propellant can lead to erratic burning that can break the grain apart and/or potentially overpressurize the motor. Not only is this dangerous, but the payload could be destroyed or lost. Some geometries (i.e. internal voids or intricate structures) cannot be cast and there is no consistent nor economical way to functionally grade grains made of multiple propellant formulations at fines scales (~ mm) without the risk of delamination between layers or the use of adhesives, which significantly lower performance. If one could manufacture grains in such a way, then one would have more control and flexibility over the design and performance of a SRM. However, new manufacturing techniques are required to enable innovation of new propellant grains and new analysis techniques are necessary to understand the driving forces behind the combustion of non-traditionally manufactured propellant.</p> <p>Additive manufacturing (AM) has been used in many industries to enable rapid prototyping and the construction of complex hierarchal structures. AM of propellant is an emerging research area, but it is still in its infancy since there are some large challenges to overcome. Namely, high performance propellant requires a minimum solids loading in order to combust properly and this translates into mixtures with high viscosities that are difficult to 3D print. In addition, it is important to be able to manufacture realistic propellant formulations into grains that do not deform and can be precisely functionally graded without the presence of defects from the printing process. The research presented in this dissertation identifies the effect of a specific AM process called Vibration Assisted Printing (VAP) on the combustion of propellant, as well as the development of binders that enable UV-curing to improve the final resolution of 3D printed structures. In addition, the combustion dynamics of additively manufactured layered propellant is studied with computational and experimental methods. The work presented in this dissertation lays the foundation for progress in the developing research area of additively manufactured energetic materials. </p> <p>The appendices of this dissertation presents some additional data that could also be useful for researchers. A more detailed description of the methods necessary to support the VAP process, additional viscosity measurements and micro-CT images of propellant, the combustion of Al/PVDF filament in windowed propellant at pressure, and microexplosions of propellant with an Al/Zr additive are all provided in this section. </p>

Microsieves are permeable membranes with excellent properties for filtration applications. In this thesis the inkjet-technology is applied (1) to manufacture micro-porous microsieves, and (2) to reinforce the mechanical stability of float-cast, nano-porous microsieves: (1) The current process for inkjet-printed microsieves includes a manual step which is substituted by inkjet printing in order to increase the level of automation. The obtained microsieves are characterized regarding the pore size distribution. Effects which occur during the manufacture and broaden the pore size distribution are identified. Based on the results, the process is improved to obtain fully inkjet-printed microsieves with a narrowed pore size distribution. (2) The mechanical stability of fragile, float-cast microsieves is improved by the application of inkjet-printed reinforcement patterns on top of the microsieves. A machine is built to combine both technologies of float-casting and inkjet printing. The printing process is improved to manufacture reinforcement patterns of well-defined geometry. / Mikrosiebe sind permeable Membranen mit herausragenden Eigenschaften für die Anwendung in der Filtration. In der vorliegenden Dissertation wird die Inkjet-Drucktechnologie angewandt, um (1) mikroporöse Mikrosiebe herzustellen und (2) nanoporöse Mikrosiebe mechanisch zu stabilisieren: (1) Die Herstellung von Mikrosieben mittels Inkjet-Druck beinhaltet momentan einen manuellen Schritt, der durch einen Inkjet-Druckschritt ersetzt wird, um den Automatisierungsgrad des Verfahrens zu erhöhen. Die Mikrosiebe werden bezüglich der Porengrößenverteilung untersucht. Auftretende Effekte, die die Porengrößenverteilung verbreitern, werden identifiziert. Aus den Resultaten dieser Analyse wird der Prozess optimiert, um Mikrosiebe mit einer engen Porengrößenverteilung herzustellen. (2) Die mechanische Stabilität von fragilen Mikrosieben, die mittels Float-Casting hergestellt werden, wird durch das Aufbringen einer Stützstruktur mittels Inkjet-Druck verstärkt. Ein Maschinensetup wird aufgebaut um beide Technologien des Float-Castings und des Inkjet-Drucks zu kombinieren. Weiterhin wird der Prozess dahingehend optimiert, Stützstrukturen mit wohl-definierten Parametern zu erzielen.

Synthetic, self-oscillating vocal fold (VF) models are physical models whose life-like vibration is induced and perpetuated by fluid flow. Self-oscillating VF models, which are often fabricated life-size from soft silicone elastomers, are used to study various aspects of voice biomechanics. Despite their many advantages, the development and use of self-oscillating VF models is limited by the casting process used to fabricate the models. Consequently, this thesis focuses on the development of 3D printing processes for fabricating silicone VF models. A literature review is first presented which describes three types of material extrusion 3D printing processes for silicone elastomers, namely direct ink writing (DIW), embedded 3D printing, and removable-embedded 3D printing. The review describes each process and provides recent examples from literature that show how each has been implemented to create silicone prints. An embedded 3D printing process is presented wherein a set of multi-layer VF models are fabricated by extruding silicone ink within a VF-shaped reservoir filled with a curable silicone support matrix. The printed models successfully vibrated during testing, but lacked several desirable characteristics which were present in equivalent cast models. The advantages and disadvantages of using this fabrication process are explored. A removable-embedded 3D printing process is presented wherein shapes were fabricated by extruding silicone ink within a locally-curable support matrix then curing the silicone ink and proximate matrix. The printing process was used to fabricate several geometries from a variety of silicone inks. Tensile test results show that printed models exhibit relatively high failure strains and a nearly isotropic elastic modulus in directions perpendicular and parallel to the printed layers. A set of single-material VF models were printed and subjected to vibration testing. The printed models exhibited favorable vibration characteristics, suggesting the continued use of this printing process for VF model fabrication. A micro-slicing process is presented which is capable of creating gcode for 3D printing multiple materials in discrete and mixed ratios by utilizing a previously-sliced single-material shape and a material definition. An important advantage of micro-slicing is its ability to create gcode with a mixed-material gradient. Initial test results and observations are included. This micro-slicing process could be used in material extrusion 3D printing