Experimental and Numerical Analysis of Mold Filling in Rotational Molding

Abstract

This work focuses on the development of a numerical mold filling simulation for the rotational molding process. In the rotational molding process, a dry fiber preform is placed in a mold and impregnated with a thermoset matrix under rotation. Additionally, metallic load introduction elements can be inserted into the mold and joined with co-curing or form-fit, resulting in hybrid drive shafts or tie rods. The numerical model can be used to simulate the impregnation of the preform. Based on the resin transfer molding process, an OpenFOAM solver is extended for the rotational molding process. Permeability, kinetic and curing models are selected and adapted to the materials used. A wireless measurement solution with a capacitive sensor is developed to validate the model. Comparisons between measurements and numerically calculated impregnation times to reach the capacitive sensor with the matrix show good quality of the developed model. The average deviation between calculated result and measured mean values in the experiment is 43.8% the maximum deviation is 65.8% . The model can therefore be used to predict the impregnation progress and the curing state.

Development of an Ultrasonic Method for the Quality Control of Polyethylene Tanks Manufactured Using Rotational Molding Technology

“…In rotational molding, the raw material is distributed over the inner surface of the cavity of the rotating mold, and the simultaneous heating of the mold causes it to melt with the formation of a thin coating in the form of a shell [ 21 , 22 , 23 , 24 ]. In the second stage of the process, liquid bridges are formed between the plastic particles to be fused, retaining microscale air bubbles, which should disappear in the subsequent compaction stage, and all this takes place at high temperatures above the melting point of polyethylene [ 25 ].…”

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…The selection of appropriate rotational speeds for the mould is often done by trial and error [21]. To save time, a computer simulation package was developed especially for rotational moulding analysis [22]. The simulation package makes it possible to select the appropriate shape of a moulded part and predict the wall thickness of the part.…”