Control of the metering phase in injection moulding on the basis of process parameters for optimisation of melt homogeneity, plasticising performance and energy consumption (OptiPlast)

• Applicants: Professor Dr.-Ing. Christian Hopmann; Professor Dr.-Ing. Volker Schöppner
• Subject Area: Plastics Engineering
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512289658

Due to the translatory backward movement of the screw during injection moulding, the effective screw length decreases during metering. In connection with the cyclic operation of the injection moulding process, this leads to an inhomogeneous axial temperature profile of the melt in the screw antechamber. Such temperature inhomogeneity can have a negative effect on the resulting component properties and limits the maximum metering stroke of the injection moulding screw. In addition to the melt homogeneity, there are two other criteria for the metering phase: the plasticising performance (mass throughput) and the energy consumption. If the plasticising capacity is too low or the dosing time too long, the cycle time increases. This reduces the economic efficiency of the process. Since a large part of the energy demand in the injection moulding process is accounted for by plasticising, the metering phase is also of great importance in terms of energy. The aim of this project is to investigate the interrelationships between process variables, material properties, process parameters and the resulting quality variables axial melt temperature distribution in the screw antechamber, metering time and energy demand with accompanying modelling of the plasticising and standstill phase and subsequent implementation in PSI (Parderborner Spritzgießsimulation). This fundamental investigation is intended to generate important findings for the subsequent development and implementation of a control system based on process parameters in order to meter the melt as homogeneously and energy-efficiently as possible while specifying the dosing time. This is to be achieved in particular for critical conditions such as a large dosing stroke and a short cycle time. This understanding should help to exploit the potential of modern injection moulding machines in terms of metering volume and plasticising performance and to reduce scrap as well as material and energy costs.

• DFG Programme: Research Grants