In the Freeze-form Extrusion Fabrication (FEF) process, extrusion-on-demand (EOD) refers to the ability to control the start and stop of paste extrusion on demand and is vital to the fabrication of parts with complex geometries. This paper describes the development of EOD for ceramic FEF through modeling and control of extrusion force, selection of appropriate process parameters, and a dwell technique for start and stop of extrusion. A general tracking controller with integral action is used to allow tracking of a variety of reference forces while accounting for the variability in the paste properties. Experiments are conducted to model the process and tune the controller. The developed technique for EOD is demonstrated to fabricate a number of cross sections and three-dimensional parts from alumina paste.
T. Oakes et al., "Development of Extrusion-on-Demand for Ceramic Freeze-Form Extrusion Fabrication," Proceedings of the 20th Annual International Solid Freeform Fabrication Symposium (2009, Austin, TX), pp. 206-218, University of Texas at Austin, Aug 2009.
20th Annual International Solid Freeform Fabrication Symposium (2009: Aug. 3-5, Austin, TX)
Mechanical and Aerospace Engineering
Intelligent Systems Center
Article - Conference proceedings
05 Aug 2009