Investigation of Part Detachment Process from Printed Circuit Boards for Effective Recycling Using Particle-Based Simulation

Abstract

For the establishment of appropriate recycling process, the delamination of electric components from printed circuit boards (PCBs), which are major components of e-waste, is expected, because some of useful critical metals are concentrated in speci c components. However, the knowledge about the mechanism of the delamination process in a drum typed agitation mill is still limited and uncertain. To better comprehend the mechanism, in this study, the particle-based simulation and comminution tests using handmade PCBs were conducted. The behavior of PCBs and the air ow in the mill having exible chains was simulated by the discrete element method (DEM) coupled with computational uid dynamics (CFD). To model the shape of PCBs, the particle based rigid body model was introduced into the DEM. Since this model could not directly simulate the breakage phenomena, collision energy was calculated to qualitatively evaluate the comminution performance. In addition, the simulation results were compared with the experimental comminution tests. This study demonstrated the behavior of PCBs and the air ow in the mill, and the effect of the air to comminution process in the mill. It was also shown that the collision energy related to parts collision was better correlated with the experimental results and this correlation can be assumed using rst order rate equation, which suggested part detachment was mainly brought by direct collision to parts in the mill.

An automated assessment method for integrated circuit chip detachment from printed circuit board by multistep binarization and template matching of X-ray transmission images

“…A drum-type chain agitation mill (cross-flow shredder, Sato Tekko Co., Ltd., Japan), specially improved for electric part detachment, was used for mechanical detachment of the PCBs. Two controlled parameters, which have great influence on parts' detachment [20,24], were selected: (1) crushing time: the time from input to output of the PCBs in the mill; and (2) rotational speed: the speed of rotation of the chains located at the bottom of the mill. Table 1 lists the five experimental conditions.…”

Effect of Agitator Shaft Direction on Grinding Performance in Media Stirred Mill: Investigation Using DEM Simulation

“…neness and sharpness of particle size distribution) is missing or still limited to empirical approaches, numerical simulations have been recently proven to be a powerful tool to investigate the milling opera-tions. Among them, the discrete element method (DEM) 9) , has been utilized to investigate the behavior of particles in mills 10,11) . As a matter of fact, because DEM allows for the simulation of the behavior of any single particle at any time in the mill, useful data such as velocity and collision energy of particles, otherwise dif cult to retrieve from experiments, can be obtained.…”