Date on Master's Thesis/Doctoral Dissertation
8-2018
Document Type
Doctoral Dissertation
Degree Name
Ph. D.
Department
Industrial Engineering
Degree Program
Industrial Engineering, PhD
Committee Chair
Stucker, Brent
Committee Co-Chair (if applicable)
DePuy, Gail
Committee Member
DePuy, Gail
Committee Member
Starr, Thomas
Committee Member
Chou, Kevin
Author's Keywords
additive manufacturing; metal; 3D printing
Abstract
Additive Manufacturing (AM) with metals has been accomplished mainly through powder bed fusion processes. Initial experiments and simulations using Material Extrusion Additive Manufacturing (MEAM) have been performed by various researchers especially using low melting alloys. Recently Stratasys Inc. submitted a patent application for the use of their Material Extrusion technology also called Fused Deposition Modeling (FDM) where they describe the process using thixotropic semi-solid alloys. Currently this process using semi-solid, engineering type alloys such as A356 or THIXALLOY 540 aluminum have not been researched to evaluate the control parameters. This research combines the in-depth knowledge of applying thixotropic semi-solid aluminum alloy processing as used in thixocasting and thixoforming with the MEAM research. Successful implementation of this metal AM process category besides powder bed fusion would result in the gain of certain MEAM process advantages like speed and ease of material handling (filament) for metal AM. In this dissertation thixotropic aluminum alloys have been identified for their applicability for MEAM and optimal pre-processing as well as thermo-mechanical handling in a nozzle has been identified. A review of the optimal heating temperature for an aligned quality of microstructure were completed to provide experimental proof of thixotropic aluminum alloy applicability. As further research aging of such alloys during isothermal holding while pausing or pure movement of a MEAM nozzle will help to derive the required cleaning processes in case the alloy develops an in-adequate microstructure. The research results build the basis for the next phases towards a larger project goal of developing a successful MEAM machine for producing aluminum alloy parts.
Recommended Citation
Herhold, Lars, "Modeling and validations of control parameters for material extrusion-based additive manufacturing of thixotropic aluminum alloys." (2018). Electronic Theses and Dissertations. Paper 3055.
https://doi.org/10.18297/etd/3055
Included in
Manufacturing Commons, Mechanics of Materials Commons, Metallurgy Commons, Other Mechanical Engineering Commons