Development of a twin screw extruder with an integrated cooling roller system

Abstract

The Center for Advanced Manufacturing at the Potchefstroom campus of the North West University aims to develop a twin screw extruder that is able to process powder coating resin. The facility has thus far produced various components and sub systems for local and international manufacturers of extrusion products. The research presented in this thesis aims to both develop a twin screw extruder with an integrated cooling roller system and to investigate of the performance of a twin screw extruder. The development of a twin screw extruder consists of the selection of the drive section of the extruder, the complete design of a twin screw extruder gearbox, the investigation and design of a suitable barrel for the manufacturing of powder coatings as well as the development of a unique cooling roller unit for the forming of the processed product when exiting the extruder. The extruder was manufactured from the designed components and systems. It was found on further testing that it was capable of producing a powder coating resin of good quality. In order to evaluate the performance of an extruder, the transfer of energy through the extruder needs to be understood. Furthermore it is necessary to understand the theory behind each type of energy being consumed by the extruder, as well as the factors influencing the usage of that energy. The theories investigated were verified in practice by measuring the energy consumption of a twin screw extruder operated under various conditions. These tests provided a correlation between the consumption of mechanical and electrical energy. The results gave an indication of the effectiveness of the screw configuration of the processing section of the extruder, making it possible to determine how the configuration should be amended in order to improve the performance of the extruder. The two aims of the thesis were satisfactory completed. The developed twin screw extruder is able to manufacture powder coatings of good quality and the performance evaluation of a twin screw extruder was also successfully completed. It enables the manufacturer to measure and evaluate the energy consumption of the process in order to improve the performance of the extruder.