Title: Ultrasonically enhanced flow rate of polymer melt extrusion

Authors: Matthew D. Moles; Anish Roy; Vadim V. Silberschmidt

Addresses: Centre for Biological Engineering, Loughborough University, Epinal Way, Loughborough LE11 3TU, UK ' Mechanics of Advanced Materials Research Group, Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Epinal Way, Loughborough LE11 3TU, UK ' Mechanics of Advanced Materials Research Group, Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Epinal Way, Loughborough LE11 3TU, UK

Abstract: Currently, the innovation of thin-section polymeric parts formed by injection moulding is restricted by the economics and practicality of applying high levels of temperature and pressure during the manufacturing process. It is long recognised that subjecting non-Newtonian fluids to vibration can significantly enhance the flow rate and, hence, may be used to reduce pressure and thermal requirements in thin-section moulding. A new moulding process was developed using ultrasonic transducers to induce vibrations in the polymeric melt thereby enhancing the flow rate without degradation of the polymer. Generating ultrasound using piezoceramics mounted in close proximity to the extrusion die required a custom-designed heat-protected transducer stack. The device, with its extrusion die exposing the polymer melt to low-intensity vibrations, improved the flow rate of polypropylene by 33% in batch exposure mode.

Keywords: low-intensity vibration; ultrasound; polymer flow; finite element; injection moulding; transducer; piezoceramic; polypropylene; extrusion; thermal analysis.

DOI: 10.1504/IJMSI.2021.125798

International Journal of Materials and Structural Integrity, 2021 Vol.14 No.2/3/4, pp.273 - 286

Received: 31 Jul 2019
Accepted: 12 Feb 2020
Published online: 29 Sep 2022 *

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