Modeling and characterization of material deposition strategy in additive manufacturing
- WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
- Md Saidur Rahman Roney (Creator)
- Institution
- Western Carolina University (WCU )
- Web Site: http://library.wcu.edu/
- Advisor
- Nazmul Ahsan
Abstract: The capability of producing complex-shaped objects, lightweight porous objects, and handling a wide range of materials such as metals, plastics, and resins allows Additive Manufacturing (AM) technologies as a viable alternative. Despite this extensive scope, defects such as warpage, delamination, cracks, porosity, and brittleness can be detrimental to the widespread use of AM. Such defects can be mitigated by manipulating the input process parameters depending on the AM technology that is being used. Since the AM technologies primarily use a layer-by-layer material deposition strategy, many of the build part properties and defects are influenced by the material deposition pattern in service. In this research, the effect of material deposition patterns on build part properties is studied for two different AM processes, namely, Laser Powder Bed Fusion (LPBF) and Fused Deposition Modeling (FDM). Two novel material deposition patterns are investigated in this study for LPBF and FDM processes, specifically using a scan pattern and an infill pattern respectively. In the LPBF process, residual stress is analyzed for multiple scan patterns by using the Finite Volume Method (FVM). Residual stress can be responsible for possible build part warpage and is greatly dependent on the thermal gradient generated on the part during the layer-by-layer deposition. A novel scan pattern is designed to reduce the thermal gradient through a re-heating approach and by turning the scanning directions along both longitudinal and transverse directions in a periodic manner. Simulation results indicate that the proposed pattern can reduce the residual stress from the very first layer and maintain the minimum stress value through the build process as compared to the existing traditional Zigzag, Island Zigzag, and Spiral scan patterns that are commonly used. The simulation results are also comparable to studies in the literature. The residual stress for the proposed pattern can be further investigated in the future by reversing the scanning direction and implying an overlap factor between two successive scan passes. On the other hand, in the FDM process, the compressive strength of the build part for the proposed infill pattern is measured and compared with the existing Zigzag infill pattern. The infill pattern in the AM technology provides a scope for producing lightweight porous objects, and its mechanical behavior varies based on structure types and manufacturing strategies. Thus, the novel infill pattern proposed in this study enhances some of the mechanical properties and may widen the scope of a designer’s choice. The proposed infill pattern is an island type that combines the existing Zigzag and Honeycomb infill patterns such that the zigzag raster reflects the hexagonal cells oriented periodically along the island span. The experimental data demonstrate that the proposed infill pattern results in higher compressive strength and elastic modulus as compared to the Zigzag infill pattern for a similar relative infill density.
Modeling and characterization of material deposition strategy in additive manufacturing
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Created on 5/1/2023
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Additional Information
- Publication
- Thesis
- Language: English
- Date: 2023
- Subjects
- Additive manufacturing
- Manufacturing processes
- Chemical vapor deposition