Abstract
During the freeze-form extrusion fabrication process for aqueous-based pastes, the sub-zero temperature environment aids the part in maintaining its shape by freezing the water present in the paste. The paste freezes very quickly when deposited on a substrate in a freezing environment. However, as the part’s height increases, the freezing time increases as the heat conduction rate to the substrate decreases. The freezing time can exceed the time required to extrude one layer of paste due to water’s high latent heat, thus leaving the extruded paste in its semi-liquid state and causing the part to deform or even collapse. Therefore, dwell time is needed between layers, which may substantially increase the build time of the part. In this paper, the effects of the paste material, paste solids loading, convection coefficient, initial paste temperature, ambient temperature, total time between layers, and layer thickness on the freezing time of paste are investigated. The paste temperature and paste freezing time are computed for various process parameters via numerical simulation using the commercial code Fluent.
Recommended Citation
M. Li et al., "Modeling, Analysis and Simulation of Paste Freezing in Freeze-Form Extrusion Fabrication," Proceedings of the 23rd Annual International Solid Freeform Fabrication Symposium (2012, Austin, TX), pp. 734 - 747, University of Texas at Austin, Aug 2012.
Meeting Name
23rd Annual International Solid Freeform Fabrication Symposium -- An Additive Manufacturing Conference (2012: Aug. 6-8, Austin, TX)
Department(s)
Mechanical and Aerospace Engineering
Keywords and Phrases
Ceramic paste solidification; Numerical simulations
Document Type
Article - Conference proceedings
Document Version
Final Version
File Type
text
Language(s)
English
Publication Date
08 Aug 2012
Comments
This work was supported by the National Science Foundation (CMMI 0856419) and the Center for Aerospace Manufacturing Technologies at the Missouri University of Science and Technology.