Modelling trans. proc. in high-perform. single-screw extrud.

Single-screw extrusion is a key technology for producing a wide range of plastic products such as pipes, films, sheets, profiles, and coatings, and is also widely used for plastic waste recycling. With more than 100 million tonnes processed annually worldwide, it significantly contributes to Austrias value creation and supports meeting EU recycling targets. At the core of the process is the extruder: a rotating screw inside a stationary barrel. The screw feeds plastic granules or powder, melts and homogenises the material, and pumps it through a shaping die. Rising demands for productivity and quality are pushing traditional screw designs to their limits especially when processing renewable, heat-sensitive plastics with variable raw material properties. To address this, complex high-performance extruders are increasingly used, enabling gentle and efficient processing even at high throughputs. However, they are more prone to process fluctuations caused by plugging, batch variations, or material change. This calls for robust screw designs that also consider time-dependent effects in the process. In collaboration with the University of Paderborn, this project aims to develop novel simulation models that can reliably predict the time-dependent conveying and melting behaviour of high- performance extruders an aspect that is poorly understood and barely captured by existing models. As a solution approach, two computational codes for solid and melt conveying will be extended to reflect the impact of temporal fluctuations, friction conditions, and residence times in the screw channel more accurately. Application scenarios focus on pressure, temperature, and throughput variations due to plugging and material changes. The simulation results will be further validated using real-time measurements from pilot-scale extruders. Using the extended models, guidelines for improved screw designs and process settings will ultimately be derived that ensure efficient, stable, and material-friendly operating conditions even at high throughputs over long-term periods. Additionally, a sensible use of the differently resource-intensive calculation approaches within various phases of problem-solving will be proposed. The findings and advanced models will enable plastics engineers to make faster, more reliable decisions and optimisations also for demanding extrusion processes. This will result in time, cost, and resource savings, and support a more competitive and sustainable plastics industry in line with European standards.