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<p>  </p> <p>Metal 3D printing is the industry standard for manufacturing experimental suppressors due to the limitations of conventional, subtractive machining methods. Long print times, difficulty sintering, and cleaning of metal 3D printed suppressor components limit the development time. Plastic printed components are able to be produced quicker, safer, and at a lower cost than their metal 3D printed counterparts. Reducing the time and cost of manufacturing will allow for an increased pace of innovations in suppressor design.</p> <p><br></p> <p>Utilizing Finite Element Analysis (FEA) in combination with Computational Fluid Dynamics (CFD) will expedite the process of designing 3D printed plastic suppressors. Solidworks FEA determined the maximum stress applied to the blast chamber of the plastic suppressor. ANSYS Fluent CFD simulations were used to qualitatively compare the sound pressure levels of an unsuppressed and suppressed 22LR pistol. Comparing the results of the CFD simulations gave insight into the effectiveness of the selected baffle structure.</p> <p><br></p> <p>A prototype 3D printed suppressor was optimized for strength according to manufacturing practices for printed plastic small arms. Testing occurred at an indoor range where peak impulse noise was measured for an unsuppressed 22LR pistol and a plastic printed suppressor. The printed suppressor reduced the small arms impulse noise from 150.5 dB(spl) to 132.4 dB(spl). Impulse noises below the pain threshold of 140 dB(spl) do not require hearing protection for operation. Utilizing FEA, CFD, and FDM prototyping methods in this work has laid the foundation for future works in the rapid prototyping and optimizations of suppressors for small arms.</p>

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Syfte: Syftet med föreliggande in vitro-studie är att undersöka passformen på ett 3D-printat polymerbaserat material för stabiliseringsskenor över tid, framställt i två olika printningsvinklar.  Material och metod: 16 provkroppar tillverkades av Keysplint soft® Clear for Carbon® Printers och delades in i två grupper beroende på printningsvinkel. Åtta provkroppar printades i 0° och åtta printades i 10°. Provkropparna genomgick termocykling på 10 000 cykler och passformen utvärderades med replikatekniken där gruppernas medelvärden jämfördes i fem parametrar mot respektive referensvärde i CAD-inställningen. Statistisk analys gjordes med One-Way ANOVA, Tukey’s test och signifikansnivån sattes till α = 0,05.  Resultat: Signifikant skillnad fanns för grupperna 0° och 0°TC i två av fem parametrar. Det fanns ingen signifikant skillnad före och efter termocykling för provkroppar printade i 10°. Signifikant skillnad hittades i tre parametrar mellan grupperna 0° och 10°. Slutsats: Inom föreliggande studies begränsningar kunde det påvisas att: 3D-printade stabiliseringsskenor med 0° printningsvinkel ger bättre passform än skenor med 10° printningsvinkel. 3D-printade stabiliseringsskenor med 10° printningsvinkel ger bättre passform över tid. / Aim: The purpose of this in vitro study is to evaluate the fit of a 3D-printed polymeric material for splint appliance over time with two different printing angles. Material and method: 16 specimens were manufactured by Keysplint Soft® Clear for Carbon® Printers and were divided in two groups. Eight specimens were printed with a 0° angle and eight printed with a 10° angle. The specimens underwent a thermal cycling of 10 000 cycles and the fit was evaluated by the replica technique. The groups mean values were compared in five parameters against the reference value in the CAD-setting. Statistical analysis was done with One-way ANOVA, Tukey’s test and significance level was set to α = 0,05. Results: Significant differences were found between groups 0° and 0°TC in two out of the five parameters. No significant differences were found before and after thermal cycling for specimens printed with a 10° angle. Significant differences were found in three parameters between groups 0° and 10°. Conclusion: Within the limitations of this study the conclusions are: 3D-printed splint appliance indicates a better fit printed with 0° angle than with 10° angle. 3D-printed splint appliance printed with the 10° angle indicates a better fit over time.

This thesis is an investigation of the current status of additive manufacturing (AM) regarding different technologies, the level of implementation in industry and the future obstacles for further implementation. As a secondary objective, an existing heatsink for electronic equipment was redesigned, adapted to and improved using the design advantages of AM, and was later manufactured through 3D-printing in aluminium (AlSi10Mg). The thesis resulted in a summarized roadmap of recommended actions for Saab Surveillance in Järfälla in the near future. And a redesigned heatsink, which was tested to hold a static pressure of 30 bar, and simulated to achieve the same pressure drop in the channel and withstand the same vibration load as the old heatsink. At the same time, the new design reduced the total weight by 20% and increased the heat transferring surface area of the channel by 100%, potentially doubling the heat transfer capability. / Detta examensarbete har undersökt den nuvarande statusen hos additiv tillverkning (AM) vad gäller olika teknologier, hur långt implementeringen i industrin kommit och framtida hinder som måste lösas för vidare implementering. Som sekundärt mål för projektet har en existerande elektronikkylare designats om och förbättrats med hjälp av designfördelarna hos AM, och tillverkades sedan genom 3D-printning i aluminium (AlSi10Mg). Arbetet har resulterat i en sammanfattad ’roadmap’ med rekommendationer för vad Saab Surveillance i Järfälla bör göra inom AM den närmaste tiden, samt en ny kylare som framgångsrikt trycktestades upp till 30 bar. Genom simuleringar visades den uppnå samma tryckfall och klara samma vibrationer som den tidigare kylaren, samtidigt som den väger 20% mindre och har en 100% ökning av kylkanalens våta area vilket potentiellt innebär en dubblering av kylförmågan.

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Additive Manufacturing (AM, 3D printing) has made significant advancements over the past decade and has become a viable alternative to traditional machining techniques. AM offers several advantages over traditional manufacturing techniques including improved geometric freedom, reduction in part lead time, cost savings, enhanced customization, mass reduction, part elimination, and remote production. There are many different AM processes with the most commonly used process being Fused Filament Fabrication (FFF). Small satellites have also made significant advancements over the past two decades with the number of missions launched annually increased by orders of magnitude over that time span. Small satellites offer several advantages compared to traditional spacecraft architectures including increased access to space, lower development costs, and disaggregated architectures. On-orbit manufacturing and assembly have become major research and development topics for government and commercial entities seeking the capability to build very large structures in space. AM is well suited on-orbit manufacturing since the process is highly automated, produces little material waste, and allows for a large degree of geometric freedom. This dissertation seeks to address three major research objectives regarding applications of additive manufacturing in space systems: demonstrate the feasibility of 3D printing an ESPA class satellite using FFF, develop a FFF 3D printer that is capable of operating in high vacuum and characterize its performance, and analyze the coupled dynamics between a satellite and a robot arm used for 3D printing in-space. This dissertation presents the design, finite element analysis, dynamic testing, and model correlation of AdditiveSat, an additively manufactured small satellite fabricated using FFF. This dissertation also presents the design, analysis, and test results for a passively cooled FFF 3D printer capable of manufacturing parts out of engineering grade thermoplastics in the vacuum of space. Finally, this dissertation presents a numerical model of a free-flying small satellite with an attached robotic arm assembly to simulate 3D printing structures on-orbit with analysis of the satellite controls required to control the dynamics of the highly coupled system. / Doctor of Philosophy / 3D printing has made significant advancements over the past decade and has become common place in offices, schools, and even the homes of hobbyist. 3D printing has become an alternative to traditional machining techniques, such as machining parts from blocks of material. 3D printing offers several advantages over traditional manufacturing techniques including improved geometry freedom, reduction in part lead time, cost savings, enhanced customization, mass reduction, part elimination, and remote production. There are many different types of 3D printing with the most commonly used process being Fused Filament Fabrication (FFF) in which a thermoplastic is melded by a hotend and then extruded through a nozzle to deposited material layer-by-layer onto a printed part. Small satellites have also made significant advancements over the past two decades with the number of missions launched annually greatly increased over that time span. Small satellites offer several advantages compared to traditional spacecraft including increased access to space and lower development costs. On-orbit manufacturing and assembly have become major research and development topics for government and commercial entities seeking the capability to build very large structures in space. This dissertation seeks to address three major research objectives regarding applications of additive manufacturing in space systems: demonstrate the feasibility of 3D printing an ESPA class satellite using FFF, develop a FFF 3D printer that is capable of operating in high vacuum and characterize its performance, and analyze the coupled dynamics between a satellite and a robot arm used for 3D printing in-space. This dissertation presents the design, analysis, and test results of AdditiveSat, a 3D printed small satellite made using FFF. This dissertation also presents the development of a FFF 3D printer capable of operating in the vacuum of space. Finally, this dissertation presents a numerical simulation that models 3D printing structures on-orbit with a small satellite equipped with a robot arm.

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