3D Model for Powder Compact Densification in Rotational Molding
TypeArticles dans des revues avec comité de lecture
During rotational molding, a loosely packed, low-density powder compact transforms into a fully densified polymer part. This transformation is a consequence of particles sintering. Powder compact density evolution of the polymer powder is measured experimentally. Obtained results show that the powder densification process consists of two stages, and its mechanism during these two stages is not the same. During the first stage, densification occurs by grains coalescence, and air between the grains escape by open pores between particles. These open pores close in time by particles coalescence progress, and remaining air entrapped in polymer melt becomes air bubbles. Surface tension, viscosity, grains size, and temperature are the controlling parameters during first stage. A three-dimensional model is proposed for the densification of polymer powder during first stage. Second stage starts after bubble forming. Diffusion is the controlling phenomena during this stage. A diffusion-based model is used for the second stage of densification. By comparing with the other models, proposed model exhibits several advantages: it is proposed in three-dimensional and takes into account the nature of layer-by-layer powder densification. Model verification by experimental data obtained for densification of two different polymers shows a close agreement between model prediction and experiments.
Showing items related by title, author, creator and subject.
HAMIDI, A; KHELLADI, Sofiane; ILLOUL, Lounès; SHIRINBAYAN, Mohammadali; BAKIR, Farid; TCHARKHTCHI, Abbas (ELSEVIER, 2015)Reactive Rotational Moulding (RRM) is the best process for producing large hollow plastic parts without weld lines. Constant quality in technical parts requires the process to be mastered by controlling on-line the main ...
RIVIERE, Sylvain; KHELLADI, Sofiane; FARZANEH, Sedigeh; BAKIR, Farid; TCHARKHTCHI, Abbas (Wiley, 2013)Reactive rotational molding (RRM) is a process to manufacture hollow plastic articles. Comparing to rotational molding of thermoplastics, it decreases the process cycle time due to the reactivity of the system. However, ...
TOMOV, Petar; KHELLADI, Sofiane; RAVELET, Florent; SARRAF, Christophe; BAKIR, Farid; VERTENOEUIL, P. (Elsevier, 2015)The injection of bubbles into an already cavitating flow is a way of influencing the typical cavitating behavior. The present article deals with experiments on aerated and non-aerated cavitation in a transparent horizontal ...
Experimental and Numerical Analysis of the Flow Inside a Configuration Including an Axial Pump and a Tubular Exchanger SOLIS, Moises; RAVELET, Florent; KHELLADI, Sofiane; BAKIR, Farid (ASME, 2010)In centrifugal and axial pumps, the flow is characterized by a turbulent and complex behavior and also by physical mechanisms such as cavitation and pressure fluctuations that are mainly due to the strong interactions ...
RAVELET, Florent; BAKIR, Farid; KHELLADI, Sofiane; REY, Robert (Elsevier, 2013)This article presents an experimental study of the hydraulic transport of very large solid particles (above 5 mm) in an horizontal pipe. Two specific masses are used for the solids. The solids are spheres that are large ...