Size Distribution and Yield of Printed Circuit Board by Cryogenic Grinding
ZHOU Cui-hong PAN Yong-tai CHANG Jun-ying KONG Hui
Department of Environmental Engineering, Beijing Institute of Pectrochemical Technology China Coal Technology & Engineering Group Tangshan Research Institute School of Mechanical Engineering in Beijing Institute of Petrochemical Technology School of Mechanical Engineering in Beijing Institute of Petrochemical Technology
Abstract：Adpoting liquid nitrogen as refrigerating medium, a cryogenic grinding system was set up to cool the printed circuit board material to its embitterment temperature. The effects of freezing temperature and processing time and setting conditions on the particle size distribution were examined. Orthogonal experiments were carried out to determine the optimal working conditions. The results show that the fractal dimension of product is 1.94 with regular particle size, and the yield of 0.5~1.4 mm particles is 43.8% when the cooling temperature is -30℃. There is no evident change of fractal dimension for different processing times. When the processing time is longer, cutter gap lower and frequency bigger, the yield is higher. The best working condition will be achieved when the crushing time is 10 min and discharge size of crusher is not less than 3 mm.
2012, Vol. 12 
