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Title: Spiral growth manufacture : a continuous additive manufacturing technology for powder processing
Author: Egan, M. J.
ISNI:       0000 0001 3441 7718
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2007
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Layered manufacturing (LM) technologies are a class of additive manufacturing processes which create three dimensional geometries directly from CAD data sequentially layer by layer. This group of technologies can process a variety of metallic, polymer and ceramic materials, as liquids, powders, or solid sheets or filaments. The material can be processed using a laser, such as melting a powder or curing a polymer resin or consolidated using a binder deposited from a print head. The build methodology used in all LM is fundamentally a start-stop process since the deposition of material and processing of each layer occurs ~equentially. Hence, the build rate can be slow (2 - 6 Layers per minute); consequently, LM technologies have largely found application as prototyping tools to speed up product development. In order for these technologies to be adopted as rapid manufacturing (RM) methods to directly manufacture complex components which cannot be manufactured by other means these speed limitations need to be addressed. This Thesis describes a new high speed RM process, Spiral Growth Manufacturing (SGM), whereby 3D parts are built by simultaneously depositing, levelling and selectively consolidating thin powder layers onto a rotating build platform. This build configuration has several advantages when compared to conventional layered manufacturing systems: firstly, the process is continuous with no layer preparation overheads; secondly, the material deposition and solidification process can be performed simultaneously by the addition of further 'build stations' radially distributed about the circumference of the machine. The work presented in this thesis focused on the design, development and testing ofthe Spiral Growth Manufacturing process. Two machines were developed; one used a bank of stationary inkjet heads to print material, either as a binder into a powder layer or as hard material from mixing two printed ink solutions and the other machine used a 90 W, flash lamp pumped Nd:YAG laser to process metal powders by localised melting. The main objective ofthe testing phase was to produce simple 3D objects from solidified layers by: a) ink jet printing a binding agent into the deposited plaster powder layers; and b) ink jet printing reactive materials to form plaster directly. The second machine was developed to exploit the considerable knowledge of Selective Laser Melting (SLM) at Liverpool, with the modification of a research SLM machine to SGM operation.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available