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Process control of profile extrusion using thermal method. Part II: Closed loop control
Author(s) -
Yang B.,
Lee L. J.
Publication year - 1988
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760281103
Subject(s) - die swell , extrusion , materials science , feed forward , die (integrated circuit) , control theory (sociology) , controller (irrigation) , loop (graph theory) , multivariable calculus , temperature control , process control , process (computing) , composite material , mechanical engineering , computer science , mathematics , control engineering , engineering , control (management) , agronomy , combinatorics , artificial intelligence , biology , nanotechnology , operating system
The analytical flow model developed in Part I was applied to the online control of profile extrusion. A rubberized polystyrene was extruded through a simple L‐shaped profile die with one thin section and one thick section. Take‐up speed was used to control the size of the extrudate, and die temperature was used to control the shape of the extrudate. Two different control algorithms, a dual single‐loop feedback PI controller and a multivariable feedforward plus feedback control method (FFC), were carried out for set point changes of the extrudate shape and size, and load disturbances of screw speed. Results showed that the PI feedback controller was satisfactory for long‐term set point changes but not for load changes. The FFC worked well for load disturbances lower than 10 cycles/min. Owing to the slow dynamic response of die temperature, the shape loop can only be controlled for long‐term disturbances.