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Additively Manufactured Polymeric Surface-Based Lattice Structures For Vibration Attenuation, Imabin Kelvin Ekpelu
Additively Manufactured Polymeric Surface-Based Lattice Structures For Vibration Attenuation, Imabin Kelvin Ekpelu
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The focus of this study was to select triply periodic minimal surface (TPMS) structures made of 3D-printed polymers. The primary variables in this study were: TPMS shape, lattice volume ratio, and lattice material. Vibration absorption was characterized by damping ratio via transmissibility at the system’s natural frequency. The vibration testing was performed using an electro-dynamic shaker, a known mass, an input/control accelerometer, and an output/response accelerometer. The 3D-printed absorber/lattice was mounted to the shaker baseplate and a mass will be mounted on top of the absorber. One accelerometer will be mounted to the shaker baseplate and the other will be …
Characterization Of Aerosol Jet Printed Silver Thin Films Sintered By A Scanning Laser, William A. Metzger
Characterization Of Aerosol Jet Printed Silver Thin Films Sintered By A Scanning Laser, William A. Metzger
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Direct write printing, which is part of additive manufacturing (AM) technology, offers unique capabilities that can complement traditional methods of electronics fabrication. Printing of electrical interconnects via aerosolization is one of the areas in AM that is very important in electronics fabrication. Post-print sintering is a critical step in printed electrical interconnects because it strongly influences the electrical resistivity of the interconnects. Interconnects require the lowest possible resistivity to achieve better performance. Thermal sintering is the most common technique employed in printed interconnects. However, it is limited to substrates that can handle the high temperature requirement for sintering. For polymers …
Direct Ink Write Processing Of Signal Crossovers Using Aerosol Jet Printing Method, Lucas A. Clark
Direct Ink Write Processing Of Signal Crossovers Using Aerosol Jet Printing Method, Lucas A. Clark
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Electronics in different applications, such as in medical imaging devices, radar systems, communication transmitters, and optical drives, often require various power and signal lines to be integrated at board level. In such cases, different lines may cross over one another in three-dimensional space for efficient electronic integration. Crossovers are usually achieved by adding additional layers to a PCB. However, these additional layers increase the cost, weight, and complexity of the component. By creating a process and structure to offer board-level heterogenous integration, these factors may be reduced. RF-DC crossovers were designed and additively manufactured using an aerosol jet printer. Benzocyclobutene …
Investigation Of Surface Roughness Effects On Additively Manufactured Metals Under Dynamic Loading, Rachel Elizabeth Tullis
Investigation Of Surface Roughness Effects On Additively Manufactured Metals Under Dynamic Loading, Rachel Elizabeth Tullis
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The as-printed surfaces of parts produced through laser powder bed fusion are significantly rougher than surfaces produced through traditional manufacturing processes. This increased roughness can have a significant impact on mechanical properties, with perhaps the most notable detriment in the fatigue life of the part. Therefore, the as-printed surface roughness in additively manufactured materials must be studied more extensively to determine its impact on fatigue performance. This work investigates the surface roughness of additively manufactured specimens through the investigation of processing parameters and their effects on surface roughness in metal additive manufacturing. Furthermore, the relationships between as-printed surface roughness and …
Printing, Characterization, And Mechanical Testing Of Additively Manufactured Refractory Metal Alloys, Brianna M. Sexton
Printing, Characterization, And Mechanical Testing Of Additively Manufactured Refractory Metal Alloys, Brianna M. Sexton
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Refractory metal alloys in the tungsten molybdenum rhenium ternary system were additively manufactured using laser power bed fusion. Four ternary alloys with varying concentrations of tungsten, molybdenum, and rhenium were manufactured and manufactured again with an addition of 1 wt% hafnium carbide. Samples were heat treated to heal cracks, reduce porosity, and reduce inhomogeneity. Material microstructure was characterized before and after heat treatment using microscopy, energy dispersive x-ray spectroscopy, and electron backscatter diffraction mapping. Mechanical testing was conducted on both three-point bend specimens and compression specimens, resulting in maximum bending strengths of 677.86 MPa, and maximum compression 0.2% yield strengths …
Texture-Driven Image Clustering In Laser Powder Bed Fusion, Alexander H. Groeger
Texture-Driven Image Clustering In Laser Powder Bed Fusion, Alexander H. Groeger
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The additive manufacturing (AM) field is striving to identify anomalies in laser powder bed fusion (LPBF) using multi-sensor in-process monitoring paired with machine learning (ML). In-process monitoring can reveal the presence of anomalies but creating a ML classifier requires labeled data. The present work approaches this problem by printing hundreds of Inconel-718 coupons with different processing parameters to capture a wide range of process monitoring imagery with multiple sensor types. Afterwards, the process monitoring images are encoded into feature vectors and clustered to isolate groups in each sensor modality. Four texture representations were learned by training two convolutional neural network …
Texture-Driven Image Clustering In Laser Powder Bed Fusion, Alexander H. Groeger
Texture-Driven Image Clustering In Laser Powder Bed Fusion, Alexander H. Groeger
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The additive manufacturing (AM) field is striving to identify anomalies in laser powder bed fusion (LPBF) using multi-sensor in-process monitoring paired with machine learning (ML). In-process monitoring can reveal the presence of anomalies but creating a ML classifier requires labeled data. The present work approaches this problem by printing hundreds of Inconel-718 coupons with different processing parameters to capture a wide range of process monitoring imagery with multiple sensor types. Afterwards, the process monitoring images are encoded into feature vectors and clustered to isolate groups in each sensor modality. Four texture representations were learned by training two convolutional neural network …
Thermal Modeling Of Coordinated Multi-Beam Additive Manufacturing, Rachel Elizabeth Evans
Thermal Modeling Of Coordinated Multi-Beam Additive Manufacturing, Rachel Elizabeth Evans
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In additive manufacturing (AM), it is necessary to know the influence of processing parameters in order to have better control over the microstructure and mechanical performance of the part. Laser powder bed fusion (LPBF) is a metal AM process in which thin layers of powdered material are selectively melted to create a three-dimensional structure. This manufacturing process is beneficial for many reasons; however, it is limited by the thermal solidification conditions achievable in the available processing parameter ranges for single-beam processing methods. Therefore, this work investigates the effect of multiple, coordinated heat sources, which are used to strategically modify the …
Defect Modeling And Vibration-Based Bending Fatigue Of Additively Manufactured Inconel 718, Wesley Earl Eldt
Defect Modeling And Vibration-Based Bending Fatigue Of Additively Manufactured Inconel 718, Wesley Earl Eldt
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Additive manufacturing (AM) is convenient for building components with complex features. However, the long-term integrity of these components is uncertain, since AM parts have defects such as pores and rough surfaces. In this work, an analytical model was developed to determine the impact of defects, and a novel bending fatigue test was used to determine the fatigue life of channeled specimens. The analytical model, based off the theory of critical distances, investigates coupled pores and predicts their potential for fatigue failure. This resulted in a maximum allowable pore size and spacing recommendation for coupled defects. Additionally, specimens with through channels …
Additive Manufacturing Techniques To Enhance The Performance Of Electronics Created On Flexible And Rigid Substrates, Aamir Hamed Hamad
Additive Manufacturing Techniques To Enhance The Performance Of Electronics Created On Flexible And Rigid Substrates, Aamir Hamed Hamad
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Different additive manufacturing (AM) methods including fused deposition modeling (FDM) and piezoelectrical drop on demand (DOD) inkjet printing have been used in printed electronics for easy production, easy integration, better performance, and low cost. These methods have been used in producing everyday smart printed electronics such as conformal antennas (planner and non-planar antennas), sensors, actuators, and solar cells created on flexible and rigid substrates. The performance of printed electronics strongly depends on printing techniques and printing resolution that enhance their electrical and mechanical properties. In this dissertation, 3D and surface printing techniques were used to enhance the performance of printed …
Rasters Vs Contours For Thin Wall Ultem 9085 Fdm Applications, Vausman Kota
Rasters Vs Contours For Thin Wall Ultem 9085 Fdm Applications, Vausman Kota
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Currently many components are additively manufactured via fused deposition modeling (FDM). However, FDM results in gaps between passes which produces a poor surface finish and porous material that is difficult to hold pressure. Commercial scale air systems require a pressure to be maintained within thin walled components with minimal post processing and clean up after fabrication. A design of experiments (DOE) was created to identify the optimal raster vs contour ratio for UTLEM 9085 CG fabricated using FDM at different build angles and wall thicknesses. A custom-built pressurized test system was developed, the leak rates were calculated and the surfaces …
Layer-To-Layer Physical Characteristics And Compression Behavior Of 3d Printed Acrylonitrile Butadiene Styrene Metastructures Fabricated Using Different Process Parameters, Sivani Patibandla
Layer-To-Layer Physical Characteristics And Compression Behavior Of 3d Printed Acrylonitrile Butadiene Styrene Metastructures Fabricated Using Different Process Parameters, Sivani Patibandla
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Three-dimensional (3D) printing, a subset of additive manufacturing, is currently being explored heavily for actual part fabrication due to its ability to create complex objects with intricate internal features. There are several 3D printing technologies; however, the extrusion-based technology such as fused deposition modeling (FDM) is the widely used one owing to its low cost. The FDM method can be used to fabricate parts with different fill densities, fill patterns, and process parameters such as extruder temperature and print speed. In this research, influence of process parameters such as extruder temperature and speed on the physical characteristics such as the …