Design of conventional extruder die for production of semi rigid PVC pipe

Abstract

The research was directed to design an extruder die for production of semi rigid poly-vinyl-chloride ( PVC) pipes widely used as an outlet pipe in washing machines, that are very popular not only at homes but in a number factories located in Sri Lanka, belonging to certain industries including dyeing, protective clothing etc. Nevertheless extrusion dies for production of semi rigid pipes have been neither produced nor designed in Sri Lanka. Theoretical approach in the research project was based on rheology and thermodynamics of plasticized PVC melt that enabled design of the extrusion die considering the specialties of the selected material and processing limitations. The carried out research consisted of two parts. Firstly to come up with a general solution package that was used to derive dimensions when information about the input material and the expected output was given. Secondly, using the package to design the die for a special application of the desired dimensions. An Excel spread sheet was developed that embodied the theoretical aspects of the research project. Changing the indicated input parameters, spread calculated and produced the dimension of the desired die. A sequence of calculations and AutoCAD diagrams were produced for the specific die requirements. With this information at hand, Sri Lankan industries can start manufacture of the extruder dies for production of plasticized PVC pipes on a good theoretical basis ensuring success, instead importing.