pps proceeding - Abstract Preview
pps proceeding
Symposium: S01 - Blow Molding, Thermoforming and Rotomolding
Oral Presentation
 
 

Modelling and Prototyping of the Centrifugal Casting Process of Paraffin-Based Thermoplastic Polymers

Masato Davide (1)*, Lucchetta Giovanni (1)

(1) University of Padova - Padova - Italy

Centrifugal casting is a casting technique that is used for the manufacturing of thick-walled paraffin cylinders, which are difficult to cast by other means. A permanent axisymmetric mold is continuously rotated about its longitudinal axis at high speed as the molten polymer is poured. The liquid paraffin is centrifugally thrown towards the mold wall, where it solidifies after cooling. The casting is a thick-walled cylinder with an inner circular port. The technology is used to help avoid cracking and void formation inside the solid paraffin as it cools. These voids are formed because the liquid paraffin shrinks upon cooling by 15-25% depending on the grade of wax. In this work, the centrifugal casting process for the manufacturing of paraffin cylinder was modelled and prototyped. A numerical model of growth and dissolution of bubbles during centrifugal casting was developed for the prediction of the quality of the casting. The numerical solution of the model, which captures the combined effects of buoyancy, drag and diffusion, allowed the prediction of the time required to bubbles to either dissolve into the molten polymer or to leave the region of interest. Moreover, the influence of process parameters on the mechanical properties of the final casting was firstly investigated on a small scale, and then verified on a bigger scale.