Abstract
In anticipation of a new selective grinding technique for printed circuit board (PCB) scraps, this study explored the kinetics of the impact grinding of copper and phenol resin used in PCBs as the base material. The selective and breakage functions of these materials were measured and grinding matrices were determined. Then the variation of the particle size distribution as a function of the impact velocity and grinding time was investigated by model calculation. As a result, it was indicated that the grinding rate of the phenol resin was much higher than that for the copper and that the optimum conditions for increasing the difference in size between copper and phenol resin particles are an impact velocity of 50–60 m/s and grinding time of approximately 6.0 s. These values are also applicable to the grinding of a printed circuit board scrap; Newton’s efficiency as a parameter of the selective grinding effect reached 57%, which is approximately 1.4 times as large as that for the conventional impact grinding method.
