MANUFACTURING OF THE COMPOSITE SCREW ROTORS BY RESIN TRANSFER MOLDING

Abstract

A screw-type pump with at least two rotors that ale composed of male and female rotors with helical extending lands and grooves is increasingly used because it has a smaller weight to power ratio and produces less noise and vibration compared to conventional reciprocating pumps. Most male and female rotors of the screw type pump have been manufactured by machining. The manufacturing time is long because the amount of material cut-away is considerable and the manufacturing cost is high because the screw rotors have a complicated shape and require high degree of accuracy in machining. Therefore, there are many attempts to manufacture the screw rotors with plastics and ceramics using different manufacturing methods such as injection molding and casting. Since the lands of rotors manufactured with polymer composite materials have resilient deflecting characteristics when clashed with other rotors, in this paper, the composite screw rotor was manufactured with chopped carbon fiber reinforced epoxy composite materials by resin transfer molding. The interfacial strength between the screw and the aluminum core shaft was tested with respect to the knurling size of the surface of the aluminum core shaft and the surface treatment. Also, the flexural strength and coefficient of thermal expansion were tested. Using the measured data, the composite screw rotors were manufactured by resin transfer molding.