Minimizing the Synthesis Time of Nanostructured Powders in Planetary Mills using Biogeography-based Optimization (BBO) Algorithm

Abstract

A key objective in processing of nanostructured powders via high-energy ball milling is to minimize the synthesis time. This paper presents the application of biogeography-based algorithm for optimization of milling parameters in order to minimize the synthesis time of nanostructured powders in planetary mills. At first a direct relationship between the inverse of the milling time and the power of the planetary mill was established, which allows the validation of theoretical models proposed in the literature for the energy transfer in milling devices and the comparison of milling equipment efficiencies. Afterwards, based on the obtained relation, eight design parameters in milling, namely, number of balls, ball diameter, vial radius, vial height, ball diameter distribution coefficient, plate spinning rate, vial spinning rate and distance between the center of the plate and the center of the vial were optimized. Using these optimized variables in milling process the energy transferred to the raw materials was maximized or in the equivalent expression the synthesis time of nanostructured powders was minimized. At the end, a test case was solved to demonstrate the effectiveness and accuracy of the proposed design. Computational results showed that the proposed optimization algorithm is quite effective and powerful in optimizing the planetary mills.

Keywords: Nanostructured powders, milling, optimization, planetary mill,
BBO algorithm