Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 47 for “"Laser Sintering"”.
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Indirect selective laser sintering of ceramics
… particles together during shaping. Selective Laser Sintering (SLS) is capable of producing small complex polymer features, but how this capability translates to indirect SLS of ceramics is an open question. This dissertation aims to systematically investigate the limitations of using indirect …
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Direct selective laser sintering of aluminium alloy powders
… by studying the effect of powder properties and laser processing parameters on the microstructures and properties of both single layer and multiple layer builds. On the basis of experimental evidence, the SLS/SLM of aluminium powders could be categorised into full melting (SLM) which was found to …
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Development of low alloy steel by direct metal laser sintering
… corrosion study is conducted on direct metal laser sintered parts in order to evaluate the factors which lead to corrosion. The main objectives of this effort are to produce mechanical properties of steel that are comparable to wrought 4340 and to understand the factors which influence the …
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Direct laser sintering of stainless steel : thermal experiments and numerical modelling
… Layers of powder material are bonded by a laser beam to rapidly manufacture three dimensional freeform models. In this work, the direct SLS of room temperature single-phase steel powder beds is researched. Two approaches are adopted: - Experimental analysis of heat transfer in the process; …
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Modeling Heat Transfer and Densification during Laser Sintering of Viscoelastic Polymers
Laser sintering (LS) is an additive manufacturing process which uses laser surface heating to induce consolidation of powdered materials. This work investigates some of the process-structure-property relationships for LS of viscoelastic polymers. A one-dimensional closed-form analytical solution …
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Finite element analysis of curl development in the selective laser sintering process
Selective laser sintering (SLS) is a rapid prototyping process, which operates by using a laser to locally heat an area within a layer of powder material, causing it to fuse together, creating a thin cross-section of solid material. 3D shapes are built by repeatedly depositing a layer of fresh …
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Direct Metal Laser Sintering of Titanium implant with Tailored structure and Mechanical Properties
Direct Metal Laser Sintering has attracted much attention over the last decade for producing complex parts additively based on digital models. The capability and reliability of this process has stimulated new design concepts and has widened the manufacturing perspective of product customisation. …
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Selective laser sintering of bioactive glass scaffolds and their biological assessment for bone repair
… manufacturing techniques, like the selective laser sintering (SLS) process, provides control over pore interconnectivity, pore geometry, and the overall shape of the scaffold, which aids in repairing different regions of the bone. The main objectives of this dissertation were to develop …
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Finite element analysis of additive manufacturing of polymers using selective laser sintering, challenges and potentials
… performance of polymers produced by a selective laser sintering (SLS) process and potential applications utilizing simulation to enable faster and less costly iterative design. Utilizing AAS, the print process to create tensile test specimens was simulated and the resultant virtual parts were …
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Hydrostatic Pressure Testing of a Square-Cross Section Stainless Steel Propellant Tank Manufactured Using Selective Laser Sintering
… if parts manufactured using metal selective laser sintering (SLS) exhibit the same isotropic material properties as conventionally made metal parts. This was accomplished by performing a hydrostatic pressure test (HPT) of a metal SLS manufactured propellant tank, constructed for a …
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Microstructural Observations of Laser-Sintered Specimens for Prosthodontic Applications
ABSTRACTObjectives: Laser sintering is a recently introduced technology that has been used to prepare dental restorations from a biocompatible Co-Cr base metal alloy. The objectives of this study were to obtain detailed information about dimensional accuracy available with laser sintering, along …
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A comparative study of rapid prototyping systems
… commercial Rapid Prototyping systems: Selective Laser Sintering (SLS), PolyJet, Fused Deposition Modeling (FDM), and 3D Printing (3DP) at the University of Missouri, Columbia. The results can be used as a preliminary guide to help users determine optimal strategies for rapid prototyping system …
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Towards personal fabrications : tabletop tools for micron and sub-micron scale functional rapid prototyping
… Finally a micro-mirror array based selective laser sintering apparatus was built for the rapid, maskless patterning of PEMS. This tool was used to directly pattern metal structures, and for the rapid manufacture of elastomeric stamps for "nano embossing". Minimum feature sizes under 10 microns …
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Silicon infiltration of silicon carbide selective laser sintered preforms
… carbide preforms are created using selective laser sintering. These parts are then infiltrated with an epoxy to decrease slumping of the part. They are then infiltrated using high temperature pressureless infiltration of a silicon matrix. This materials system can be applied in a wide variety …
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A pneumatic conveying powder delivery system for continuously heterogeneous material deposition in solid freeform fabrication
… provides the potential for the Selective Laser Sintering (SLS), ThreeDimensional Printing (3DP), and Freeform Powder Molding (FPM) processes to be altered to create continuously heterogeneous material composition. The current roller distribution system needs to be replaced with a new means …
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Parametric Analysis of Particle Spreading with Discrete Element Method
… additive manufacturing methods, including direct laser sintering. Several processing parameters such as particle size, inter-particle friction, blade speed, and blade gap size affect the spreading process and, therefore, the final product quality. The objective of this study is to parametrically …
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Parametric analysis of part suitability in Additive Manufacturing
… time for parts manufactured via the Selective Laser Sintering process, utilizing specific metrics for part geometry and machine specific parameters. Key elements of the AM cost function are identified using the estimation model, paying close attention to assessing the impact of machine cost on …
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Creating Complex Hollow Metal Geometries Using Additive Manufacturing and Metal Plating
… manufacturing approach that combines selective laser sintering with an electroforming process to produce complex, hollow, metal geometries. The developed process uses electroless nickel plating on laser sintered parts that then undergo a flash burnout procedure to remove the polymer, leaving a …
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