Dynamic behavior of a single screw plasticating extruder part I: Experimental study

Abstract

The dynamic responses of a 2–1/2 inch single screw plasticating extruder and extrusion line were investigated. Step changes in screw speed, take‐up speed, back pressure, and processing materials were used to determine the transient responses of barrel pressures, die pressure, melt temperature, and extrudate thickness. Dynamic responses of the entire extrusion line can be explained by the flow mechanism of the extruder and the logical properties of the polymer used. A capillary rheometer was also used to determine if it could simulate pressure responses in the extruder for screw speed changes. Results showed that capillary rheometer was helpful in estimating the short term pressure responses in the die.

Dynamic Response of a Twin-screw Lab-size Extruder to Changes in Operating Variables

“…Feed rate disturbances were modeled by a general first order transform function. Equations [7] and [8] show first order response of die pressure and motor torque in the time domain after a step change introduction in the s domain. The experimental results and model fitted were shown in Fig.…”

“…They are also promising tools for product development and quality improvement. Dynamic analysis of extrusion data has been widely reported in the plastics extrusion literature (4,(7)(8)(9) and the same basic principles of polymer extrusion can be applied to food extrusion. However, the nature of the food ingredients, interaction between the food components, and physicochemical changes such as protein denaturation and starch gelatinization make modeling of food extrusion more complex.…”

Mathematical design theory of screw extruder used for additive manufacturing

“…Friction in the screw is a significant source of heat in the extruder. So sometimes not only external heating, but also external cooling of the extruder chamber is needed to achieve optimal temperature conditions [25,26].…”

Single screw extrusion control: A comprehensive review and directions for improvements

“…Chan and Lee [23], Chan et al [24] and Nelson et al [25] proposed Laplace transfer function models (e.g., a first order, a second order and a lead-lag) to describe dynamic responses of an extrusion process. Laplace transfer function models accounted for the basic type of temperature and pressure responses with fitting of a phenomenological kinetic-elastic model to calculate other required parameters.…”