Process Mechanisms of Single Screw Extrusion Dr Xueqin (Amy) Liu Research Assistant Intelligent System & Control School of Electronics, Electrical Engineering & Computer Science
Presentation Outline • Standard set-up of SSE • Process mechanisms • Pressure development • Inferential Viscosity • Laboratory SSE
Process Analysis • Identification/selection of manipulated variables, disturbance variables, and controlled variables is required for the proper design of control systems. partially reproduced from Iqbal, 2010
Process Mechanisms Clamp-ring Adapter Reproduced from Tadmor and Klein, 1970
Inferential Viscosity • In-line rheometer • Viscosity calculated from pressure drop and throughput rate (here linear with speed)
Inferential Viscosity • Can be achieved using suitable rheological model and appropriate rheological parameters • Provides initial estimate of material viscosity
Laboratory Single Screw Extruder Killion KTS-100, 25mm SSE (1995) with in-line rheometer
References • Cogswell, F. N., Polymer melt rheology: A guide for industrial practice. Abington: Woodhead Publishing Ltd, 1981. • Han, C. D., What is the role of "pressure" in the use of capillary and slit flows to determine the shear-rate dependent viscosity of a viscoelastic fluid. Polymer engineering and science, 2008, 48(6): 1126 - 1140. • Liang, J.. Estimation of entry pressure drop during conical die flow of carbon black-filled rubber compound. Journal of Reinforced Plastics and Composites, 2004, 23(3): 1355-1363. • Cogswell, F. N., Measuring the extensional rheology of polymer melts. Transactions of the Society of Rheology, 1972, 16(3): 383 - 403. • C. Rauwendaal, Polymer Extrusion (4th edition). Carl Hanser Verlag, Munich, 2001.
References • Cogswell, F. N., et al., Converging Flow of Polymer Melts in Extrusion Dies. Polymer Engineering and Science, 1972,12: 64 - 73. • McAfee, M. (2005). A soft sensor for viscosity control of polymer extrusion. Phd thesis, Queen’s University Belfast. • M. H. Iqbal, U. Sundararaj, and S. L. Shah, “New approach to develop dynamic gray box model for a plasticating twin-screw extruder,” Industrial & Engineering Chemistry Research, vol. 49, no. 2, pp. 648–657,2010. • X. Liu, K. Li, M. McAfee, and J. Deng, “‘soft-sensor’ for real-time monitoring of melt viscosity in polymer extrusion process,” in Decision and Control (CDC), 2010 49th IEEE Conference on, 2010, pp. 3469 –3474. • B. H. Maddock, “Measurement and analysis of extruder stability,” SPE Journal, vol. 20, pp. 1277–1283, 1964.
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