Determination of the correlation between pressure fluctuations, thickness fluctuations, melting degree and product quality in extrusion

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Single-screw extrusion is one of the core competencies of plastics processing. Against the background of economic conditions, increasing the throughput of processing machines while maintaining a high melt quality is one of the primary development goals of many machine manufacturers. This requires a purposeful screw design. In the intended research proposal, the correlation between the processing parameters and the melt and product quality is to be investigated using an extruded pipe profile. The aim is to identify a quality limit above which the melt quality at the extruder outlet is no longer sufficient to allow the extrusion of a high-quality product. This quality limit is to be considered mainly as a function of the location of the end of the melting process in the extruder, but other influence factors are also to be considered.In the preliminary investigations it is necessary to identify both important and non-relevant influencing factors in order to create a selection of the factors to be investigated on the basis of the results. In addition, the influence of various common extruder screws is considered. The selected influencing factors are then investigated systematically and to the required extent.The experimental investigations are analytically simulated with the corresponding process parameters and the simulations are validated on the basis of the experimentally generated data. The simulations allow an insight into the processes in the extruder, such as determining the location of the end of the melting process.The aim of the investigations is to develop a model which, based on the processing parameters and analytically applicable simulations, allows a prediction of the expected melt quality at the extruder outlet. The aim is to provide a tool for the screw design process which can quickly and cost-effectively check the requirements placed on the screw to be designed.