Thesis
Investigation of a laser-assisted fused deposition modeling process for enhanced inter-layer strength
Washington State University
Master of Science (MS), Washington State University
12/2017
DOI:
https://doi.org/10.7273/000004197
Handle:
https://hdl.handle.net/2376/125255
Abstract
One of the main material extrusion based Additive Manufacturing techniques, Fused Deposition Modeling, fabricates the 3-dimension part by depositing layers of semi molten polymer (thermoplastic) onto a platform in the prescribed manner governed by CAD model. The thermal profile of filament roads at bonding interface plays critical role in determining the quality of weld/bond that forms between them, which ultimately determines the strength of final part. From the primary tensile testing results, its established that parts printed using this technique has strength as low as 30% in the build direction compared to that along the filament. To enhance the inter-layer wetting and diffusion, re-melting of the substrate at bonding interface is proposed. First, we have considered the thermal profile of substrate and extrudate in details by using infrared camera and thermocouples. Then a way to maintain substrate over critical temperature before deposition of fresh filament over it is proposed which will enhance the inter-layer molecular chains diffusion. Tensile testing of part printed vertically to measure bonding quality shows an increase of 54% in interlayer strength. A set of critical parameters like maximum heat source energy density, and best-suited combination of printing speed and offset distance between nozzle tip and beam spot has also been put forth. In addition, the temperature distribution obtained along filament length over time theoretically using modeling and simulations tool as well as experimentally, helps in complete study of physics behind melted extrusion modeling. The morphology changes has been studied with Scanning Electron Microscopy and Optical Microscopy images for parts, and it’s concluded that the addition of new laser heating technique yield part with better surface quality and accuracy along with improved inter-layer strength. Finally, the increase in neck width proves enhanced diffusion along with the direct dependence of bonding strength on bonding potential.
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Details
- Title
- Investigation of a laser-assisted fused deposition modeling process for enhanced inter-layer strength
- Creators
- Piyush Suresh Mundada
- Contributors
- Kuen-Ren Chen (Advisor) - Washington State University, Mechanical and Materials Engineering, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Mechanical and Materials Engineering, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896438301842
- Language
- English
- Resource Type
- Thesis