Self-optimizing barrel temperature setting control of single screw extruders for improving the melt quality

Since extrusion is one of the most important manufacturing processes due to the increasing demand of polymer products, the melt quality of the polymer plays a crucial role. Indeed, the melt quality depends on the condition of preparing and processing the polymer. In fact, the resulting melt quality is highly reliant on the parameter settings of the extruder. A thermal homogeneous polymer melt as well as an increase of the throughput is conceivable. Moreover, an improper barrel temperature setting can lead to a deterioration of the material. Nowadays, the temperature of the barrel is either set with the help of an experienced process engineer or by seeking for advice from the resin manufacturer. If neither option is possible the barrel temperature can be set by applying trial and error experiments. Rather than assuming the “correct” barrel temperature setting, it is more efficient to identify the correct barrel temperature setting by means of measured quality criterions. In the 21^st century, digitization permeates all areas of our lives and presents the industry with new challenges. The affected industry operators have to react promptly to the changes in the process of digitalization supposing to ensure long-term competitiveness. However, extrusion is one of the most important production processes in the polymer industry and is also facing new challenges. One of these challenges is the regulation of the barrel temperature control which influences the melt quality and thus the product quality. Certainly, the expert knowledge of the experienced machine operators represents a transitional solution which needs to be implemented by a digital and more intelligent solution. In this manner, an extruder that self-corrects the barrel temperature with the objective to meet an optimal barrel temperature setting regardless of the screw geometry and the resin is highly preferable. This is why the aim of this work concentrates on the development of a suitable control algorithm that independently detects the optimum process and controls the optimum barrel temperature setting. For this reason, rules of behavior are derived from the process behavior of the extruder in terms of its use as a basis for intelligent barrel temperature control.